This document presents a thesis on the structural behavior of hybrid and ductal decked bulb T-beams constructed with ultra-high performance concrete (UHPC) and prestressed with carbon fiber composite cables (CFCC). The thesis introduces these innovative beam designs which aim to 1) reduce construction costs by optimizing the use of UHPC and FRP materials, 2) eliminate transverse reinforcement, 3) prevent sudden shear and flexural failures, 4) accelerate onsite construction, 5) reduce maintenance costs, and 6) allow for easier inspection. An experimental program evaluated the shear and flexural behavior of hybrid beams with UHPC in the shear spans and high-strength concrete in the middle span, and ductal beams with optimized UHPC
This document summarizes an experimental study on the flexural strengthening of continuous two-span unbonded post-tensioned concrete beams with end-anchored CFRP laminates. Five full-scale beams were tested: one control beam and four beams strengthened with CFRP laminates of varying widths and end anchorage configurations. The study found that CFRP strengthening increased the service load capacity more than the ultimate capacity. Proper end anchorage and installation of the CFRP laminates was important to achieve effective load transfer and prevent premature debonding failures. The strengthened beams exhibited higher stiffness and load capacity compared to the control beam.
1) An experimental study tested the shear performance of hybrid bridge girders with ultra-high performance concrete (UHPC) in the critical shear spans near supports and normal high-strength concrete (HSC) with steel stirrups in the midspan.
2) Two hybrid beams were constructed with UHPC in the critical shear spans without transverse reinforcement and HSC with steel stirrups in the midspan.
3) The hybrid beams were tested at varying shear span-to-depth ratios and showed higher ultimate shear resistance and energy absorption compared to beams with steel or carbon fiber reinforced polymer stirrups. The hybrid design allowed for optimal use of expensive UHPC.
IRJET- Behaviour of CFST Column Element with & without Shear Studs under ...IRJET Journal
This document summarizes research on the behavior of concrete-filled steel tube (CFST) columns. It discusses how CFST columns offer benefits like strength, ductility and construction efficiency compared to traditional hollow steel tubes or reinforced concrete columns. The paper reviews past research on the load-carrying capacity of CFST columns according to different design codes. It also describes finite element models and experiments that were conducted to analyze the behavior of CFST columns under axial compression loads. In particular, the research presented in the paper compares the performance of CFST column models with and without shear studs in different positions.
An Analytical Study on Static and Fatigue Analysis of High Strength Concrete ...Stephen Raj
In recent years FRP stands as a better alternative to restore and upgrade deficient structures. The deficiency may be due to change in design standards, improper construction practices (or) adverse environmental conditions. Under such circumstances, adoption of appropriate technique for restoring the structure becoming challenging task. The objective of this thesis work is to evaluate the static and fatigue response of HSC beams with externally bonded FRP laminates using ANSYS software. The modeling and analysis is done using the software for HSC beam. The beams were strengthened with FRP laminates. The models are provided with carbon types of Fiber Reinforced Polymer (FRP) laminates. The available experimental data of HSC beam in flexure behavior is the source material of this analysis work. All the relevant data are taken from that source material. The static and fatigue load cases are applied and the results are discussed. The comparison is made between the available experimental results of HSC beam with analytical based results of HSC beam.
A Review On Strengthening Of RCC Square Columns with Reinforced Concrete Jack...IRJET Journal
This document reviews strengthening of reinforced concrete square columns with reinforced concrete jacketing. It discusses how RC jacketing leads to uniformly increased strength and stiffness of columns. The durability of the original column is also improved with RC jacketing compared to other techniques. The review examines factors that influence the bond between the column and jacket, such as surface preparation, dowel bars, and transverse reinforcement. It concludes that RC jacketing is an effective and economical retrofitting technique that increases load capacity and improves structural performance of columns.
IRJET- Experimental Investigation on Bond Strength in Self-Compacting Con...IRJET Journal
The document summarizes an experimental study on the bond strength between self-compacting concrete and steel tubes in concrete-filled steel tube (CFST) columns. 27 push-out tests were conducted on circular CFST specimens varying cross-sectional dimensions, steel type, concrete type (normal vs self-compacting), concrete age, and height-to-diameter ratio. A literature review covered previous studies investigating effects of dimensions, steel type, concrete strength and interfaces on bond strength. The objectives were to use self-compacting concrete in CFSTs, determine bond strength for different ratios and properties, and model bond strength prediction.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document summarizes an experimental study on the flexural strengthening of continuous two-span unbonded post-tensioned concrete beams with end-anchored CFRP laminates. Five full-scale beams were tested: one control beam and four beams strengthened with CFRP laminates of varying widths and end anchorage configurations. The study found that CFRP strengthening increased the service load capacity more than the ultimate capacity. Proper end anchorage and installation of the CFRP laminates was important to achieve effective load transfer and prevent premature debonding failures. The strengthened beams exhibited higher stiffness and load capacity compared to the control beam.
1) An experimental study tested the shear performance of hybrid bridge girders with ultra-high performance concrete (UHPC) in the critical shear spans near supports and normal high-strength concrete (HSC) with steel stirrups in the midspan.
2) Two hybrid beams were constructed with UHPC in the critical shear spans without transverse reinforcement and HSC with steel stirrups in the midspan.
3) The hybrid beams were tested at varying shear span-to-depth ratios and showed higher ultimate shear resistance and energy absorption compared to beams with steel or carbon fiber reinforced polymer stirrups. The hybrid design allowed for optimal use of expensive UHPC.
IRJET- Behaviour of CFST Column Element with & without Shear Studs under ...IRJET Journal
This document summarizes research on the behavior of concrete-filled steel tube (CFST) columns. It discusses how CFST columns offer benefits like strength, ductility and construction efficiency compared to traditional hollow steel tubes or reinforced concrete columns. The paper reviews past research on the load-carrying capacity of CFST columns according to different design codes. It also describes finite element models and experiments that were conducted to analyze the behavior of CFST columns under axial compression loads. In particular, the research presented in the paper compares the performance of CFST column models with and without shear studs in different positions.
An Analytical Study on Static and Fatigue Analysis of High Strength Concrete ...Stephen Raj
In recent years FRP stands as a better alternative to restore and upgrade deficient structures. The deficiency may be due to change in design standards, improper construction practices (or) adverse environmental conditions. Under such circumstances, adoption of appropriate technique for restoring the structure becoming challenging task. The objective of this thesis work is to evaluate the static and fatigue response of HSC beams with externally bonded FRP laminates using ANSYS software. The modeling and analysis is done using the software for HSC beam. The beams were strengthened with FRP laminates. The models are provided with carbon types of Fiber Reinforced Polymer (FRP) laminates. The available experimental data of HSC beam in flexure behavior is the source material of this analysis work. All the relevant data are taken from that source material. The static and fatigue load cases are applied and the results are discussed. The comparison is made between the available experimental results of HSC beam with analytical based results of HSC beam.
A Review On Strengthening Of RCC Square Columns with Reinforced Concrete Jack...IRJET Journal
This document reviews strengthening of reinforced concrete square columns with reinforced concrete jacketing. It discusses how RC jacketing leads to uniformly increased strength and stiffness of columns. The durability of the original column is also improved with RC jacketing compared to other techniques. The review examines factors that influence the bond between the column and jacket, such as surface preparation, dowel bars, and transverse reinforcement. It concludes that RC jacketing is an effective and economical retrofitting technique that increases load capacity and improves structural performance of columns.
IRJET- Experimental Investigation on Bond Strength in Self-Compacting Con...IRJET Journal
The document summarizes an experimental study on the bond strength between self-compacting concrete and steel tubes in concrete-filled steel tube (CFST) columns. 27 push-out tests were conducted on circular CFST specimens varying cross-sectional dimensions, steel type, concrete type (normal vs self-compacting), concrete age, and height-to-diameter ratio. A literature review covered previous studies investigating effects of dimensions, steel type, concrete strength and interfaces on bond strength. The objectives were to use self-compacting concrete in CFSTs, determine bond strength for different ratios and properties, and model bond strength prediction.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Experimental study of flax frp tube encased coir fibre reinforced concrete co...Libo Yan
The use of natural fibres as building materials is benefit to achieve a sustainable construction. This paper
reports on an experimental investigation of a composite column consisting of flax fibre reinforced polymer
(FFRP) and coir fibre reinforced concrete (CFRC), i.e. FFRP tube encased CFRC (FFRP-CFRC). In this
FFRP-CFRC, coir fibre is the reinforcement of the concrete and FFRP tube as formwork provides confinement
to the concrete. Uniaxial compression and third-point bending tests were conducted to assess the
compression and flexural performance of the composite column. A total of 36 specimens were tested. The
test variables were FFRP tube thickness and coir fibre inclusion. The axial stress–strain response, confinement
performance, lateral load–displacement response, bond behaviour and failure modes of the composite
column were analysed. In addition, the confined concrete compressive strength was predicted
using existing strength equations/models and compared with the experimental results. Results indicate
that the FFRP-CFRC composite columns using natural fibres have the potential to be axial and flexural
structural members.
Seismic response of frp strengthened rc frameiaemedu
This document discusses research on strengthening reinforced concrete (RC) frames with fiber-reinforced plastic (FRP). It summarizes previous studies on using FRP to strengthen beams and columns. However, few studies have analyzed FRP-strengthened RC frames as a whole system. The present study uses finite element analysis to model RC frames strengthened with varying FRP thicknesses and investigates their seismic response. Models of 2-bay, 3-story and 3-bay, 5-story frames are analyzed for different crack locations. The results are intended to help develop design criteria for seismic retrofitting of RC frames with FRP.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
EFFECT OF CARBON LAMINATION ON THE STRENGTH OF CONCRETE STRUCTURESIAEME Publication
This work consists of preparation and testing of different structural model like cubes, Beams and Columns. They are tested for Compression test, Flexural test and Split tensile Test. The comparison between Laminated and un-laminated Structural Models was made in order to know how much strength gain after testing of these structural models, so by which the rehabilitation of any structure can be done without demolishing it with less weight to strength ratio.
This document presents an experimental and analytical study comparing the structural behavior of composite concrete slabs with profiled steel decking. 18 full-scale slab specimens were tested under different shear span lengths to evaluate the longitudinal shear bond strength between the concrete and steel deck. The experimental results were compared to analytical calculations using the m-k method and partial shear connection method from Eurocode 4. The m-k method was found to provide a more conservative estimate of load-carrying capacity than the partial shear connection method, with generally good agreement between experimental and analytical values.
The document summarizes Ranjit Kumar Sharma's thesis defense on the structural behavior of hybrid and ductal decked bulb T beams prestressed with carbon fiber composite cables (CFCC). The experimental program involved shear and flexural testing of hybrid and ductal beams with varying shear span-to-depth ratios. Research findings showed the beams failed in diagonal shear or flexural compression. Crack patterns and load-deflection responses are presented. The research aims to examine shear behavior without stirrups and evaluate design guidelines for hybrid and ductal beams.
This document reviews research on the bond strength between steel and concrete in concrete-filled steel tubes (CFSTs). It summarizes several studies that investigated factors affecting bond strength like cross-sectional dimensions, steel type, concrete properties, temperature, and interface characteristics. The review finds that 70% of bond strength comes from friction at the interface, while 30% comes from chemical adhesion and mechanical interlocking. It also identifies ways to improve bond strength, such as using expansive concrete, increasing concrete strength, and adding perforations to the steel tube interior.
Effect of width and layers of GFRP strips on deflection of Reinforced Concret...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This study uses explicit finite element analysis to predict the behavior of fiber-reinforced polymer (FRP) composite grid reinforced concrete beams subjected to four-point bending. The finite element models accurately captured the load-deflection behavior observed experimentally. A substructure model was also developed to analyze stresses in the longitudinal reinforcement at failure. This led to a proposed analysis procedure that accounts for different failure modes, providing conservative predictions of load capacity.
This study investigated the compressive strength of reinforced concrete columns wrapped with different hybrid fiber reinforced polymer (FRP) configurations. Four 150x380mm concrete columns were tested: one unconfined control column and three wrapped with different combinations of glass, basalt, and jute FRP. The column wrapped with two layers each of basalt, glass, and jute FRP (CBGJ) achieved the highest compressive strength, reaching 1000kN and exceeding the unconfined column's strength by 25%. Analysis of the load-displacement and load-strain behaviors showed that the CBGJ wrapping configuration resulted in higher displacement and strain values compared to the other specimens. The results indicate that hybrid FRP wrapping can significantly
Recycling of waste materials produced from the construction and demolition
activities is becoming a demand for modern societies willing to achieve environmental
sustainability. To date, the use of crushed concrete aggregate (CCA) in replacement of
natural coarse aggregate to produce high quality concrete is very limited. This can be
attributed to the missing information on the properties of the original concrete before
crushing, the limited data that clarifies the influence of using CCA on the material
properties of the concrete mixture as well as the overall structural behavior of the
reinforced concrete element in which it is used. An experimental testing program has
been conducted on reinforced concrete beams to assess the influence of CCA
replacement ratio on their structural performance and the results have been briefly
discussed in this paper. The primary aim of the study presented herein is to
numerically evaluate the influence of the concrete compressive strength (fcu) and the
shear span to depth ratio (a/d) on the structural performance of reinforced concrete
beams casted with two different concrete mixtures incorporating 0% and 100% CCA.
Accordingly, ten beams have been modelled using ANSYS finite element software with
two control beams being validated with the experimental data. The results
demonstrate the increase of the load carrying capacity and ductility of beams with
100% CCA with increasing the fcu. On the contrary, increasing the shear span to depth
ratio leads to the reduction in the capacity of the beams casted with the two different
concrete materials. As a final conclusion, the results of the performed numerical
analysis designate undesirable structural performance of the concrete beams with
100% CCA. Therefore, it is not recommended to use concrete mixtures with full
Developing A Prediction Model for Tensile Elastic Modulus of Steel Fiber – Ce...IJRESJOURNAL
ABSTRACT: This paper attempts to develop a prediction model that can be used in line with prescribed laboratory experiments for indirect tensile test such that tensile elastic modulus can be predicted for cement stabilized lateritic soil reinforced with steel fiber using measured properties of the material. The results of the tensile elastic modulus obtained from the Derived Prediction Model almost nearly replicates that obtained from calculations from laboratory experimentation. Results obtained revealed that both the predicted values and calculated values have a linear correlation with an R2 of 96.4%. On this basis the Derived Prediction Model can be said to be valid within the limits of the study.
IRJET- Review on Steel Concrete Composite ColumnIRJET Journal
1. The document reviews research on steel-concrete composite columns, where steel columns are infilled with concrete. Wire mesh is welded inside steel columns to improve bond between steel and concrete.
2. Three composite columns and three reinforced concrete columns of the same size were tested and compared. The composite columns showed better structural behavior than reinforced concrete columns in terms of ultimate strength, ductility, energy absorption capacity, and stiffness.
3. The literature review discussed previous research on composite columns that found infilling concrete inside steel tubes improves tensile strength and load capacity compared to hollow steel tubes. Previous studies also showed that composite columns experienced less damage than steel-only columns under the same loads.
1) The document describes an experimental investigation of glass fibre reinforced plastic (GFRP) bridge deck panels subjected to static and fatigue loading.
2) Testing of prototype GFRP composite bridge deck panels was conducted under simulated wheel loads, with two rectangular patch loads applied symmetrically.
3) The results showed that under buckling criteria, panels failed at 123.6 kN with a deflection of 7.538mm, and under local shear criteria panels failed at 113.8 kN with a deflection of 4.057mm. Panels also resisted up to 5 million fatigue cycles.
Strengthening structures via external bonding of advanced fibre reinforced polymer (FRP) composite is becoming very
popular worldwide during the past decade because it provides a more economical and technically superior alternative
to the traditional techniques in many situations as it offers high strength, low weight, corrosion resistance, high fatigue
resistance, easy and rapid installation and minimal change in structural geometry. Although many in-situ RC beams
are continuous in construction, there has been very limited research work in the area of FRP strengthening of continuous
beams.
This document discusses structural rehabilitation of reinforced concrete columns through reinforced concrete jacketing. It assesses different aspects of the jacketing process including anchoring added longitudinal reinforcement, interface surface preparation, spacing of added stirrups, and adding new concrete. Recommendations are provided based on research findings. Proper cleaning of holes drilled in footings is important for anchoring reinforcement. Sandblasting is an effective method for increasing surface roughness at the column-jacket interface. Published research has found that interface treatment may not be necessary for strengthening undamaged columns, but could be important for short columns.
Seismic rehabilitation of beam column joint using gfrp sheets-2002Yara Mouna
The document summarizes a study that tested different rehabilitation techniques for improving the seismic performance of reinforced concrete beam-column joints. Three beam-column joints were tested: a control specimen and two specimens that were rehabilitated using glass fiber-reinforced polymer (GFRP) sheets. The control specimen failed in a brittle shear and bond failure mode, while the rehabilitated specimens exhibited a more ductile flexural failure of the beam. The rehabilitation techniques strengthened the joint shear capacity and prevented bond-slip failures of the beam reinforcement in the joint. A simple design methodology for the GFRP rehabilitation is proposed.
Experimental and numerical study on behavior of externally bonded rc t beams ...IJARIIT
Fiber-reinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have
become structurally weak over their life span. FRP repair systems provide an economically viable alternative to traditional
repair systems and materials. In this study, an experimental investigation on the flexural behavior of RC T-beams
strengthened using glass fiber reinforced polymer (GFRP) sheets are carried out.
Reinforced concrete T beams externally bonded with GFRP sheets were tested to failure using a symmetrical two
point static loading system. Seven RC T-beams were casted for this experimental test. All of them were weak in flexure and
were having same reinforcement detailing. One beam was used as a control beam and six beams were strengthened using
different configurations of glass fiber reinforced polymer (GFRP) sheets. Experimental data on load, deflection and failure
modes of each of the beams were obtained. The effect of different amount and configuration of GFRP on ultimate load
carrying capacity and failure mode of the beams were investigated.
The experimental results show that externally bonded GFRP can increase the flexural capacity of the beam
significantly. In addition, the results indicated that the most effective configuration was the U-wrap GFRP.A series of
comparative studies on deflection between the present experimental data and results from finite element method and IS code
method were made. A future area of research are being outlined.
This document provides a summary of research on the fatigue behavior of steel structures strengthened with fiber-reinforced polymer composites. It discusses various failure modes that can occur, including adhesive failure, delamination of composites, and debonding at interfaces. The document also reviews studies on how fiber-reinforced polymer composites can improve the fatigue resistance and life of steel structures by reducing crack propagation rates and increasing load capacities. It finds that fiber-reinforced polymer jacketing is effective at confining local buckling in compression members and arresting crack growth in steel beams and plates under cyclic loading conditions.
Experimental study on flexural behavior of the self compacting concrete with ...IAEME Publication
This document summarizes an experimental study on the flexural behavior of self-compacting concrete with hybrid fibers. Tests were conducted to evaluate the compressive and flexural strength of self-compacting concrete mixtures containing different fiber combinations. Nylon e-300 microfibers and Nylon tuff macrofibers were added to self-compacting concrete mixtures in various volumes. The results showed that adding hybrid fibers improved the compressive and flexural strength properties of self-compacting concrete compared to plain self-compacting concrete.
The Primrose East Bridge project utilized new technologies including a geosynthetic reinforced soil (GRS) integrated abutment, folded plate girders, and ultra-high performance concrete (UHPC). The bridge was constructed off-site and elements were delivered and installed, accelerating construction. The GRS abutment provided rapid construction without need for cranes or piles. Folded plate girders developed at UNL were lightweight. UHPC with over 21,000 psi compressive strength resulted in narrow joints and minimal shrinkage. The project was completed and opened to traffic ahead of schedule in November.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Experimental study of flax frp tube encased coir fibre reinforced concrete co...Libo Yan
The use of natural fibres as building materials is benefit to achieve a sustainable construction. This paper
reports on an experimental investigation of a composite column consisting of flax fibre reinforced polymer
(FFRP) and coir fibre reinforced concrete (CFRC), i.e. FFRP tube encased CFRC (FFRP-CFRC). In this
FFRP-CFRC, coir fibre is the reinforcement of the concrete and FFRP tube as formwork provides confinement
to the concrete. Uniaxial compression and third-point bending tests were conducted to assess the
compression and flexural performance of the composite column. A total of 36 specimens were tested. The
test variables were FFRP tube thickness and coir fibre inclusion. The axial stress–strain response, confinement
performance, lateral load–displacement response, bond behaviour and failure modes of the composite
column were analysed. In addition, the confined concrete compressive strength was predicted
using existing strength equations/models and compared with the experimental results. Results indicate
that the FFRP-CFRC composite columns using natural fibres have the potential to be axial and flexural
structural members.
Seismic response of frp strengthened rc frameiaemedu
This document discusses research on strengthening reinforced concrete (RC) frames with fiber-reinforced plastic (FRP). It summarizes previous studies on using FRP to strengthen beams and columns. However, few studies have analyzed FRP-strengthened RC frames as a whole system. The present study uses finite element analysis to model RC frames strengthened with varying FRP thicknesses and investigates their seismic response. Models of 2-bay, 3-story and 3-bay, 5-story frames are analyzed for different crack locations. The results are intended to help develop design criteria for seismic retrofitting of RC frames with FRP.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
EFFECT OF CARBON LAMINATION ON THE STRENGTH OF CONCRETE STRUCTURESIAEME Publication
This work consists of preparation and testing of different structural model like cubes, Beams and Columns. They are tested for Compression test, Flexural test and Split tensile Test. The comparison between Laminated and un-laminated Structural Models was made in order to know how much strength gain after testing of these structural models, so by which the rehabilitation of any structure can be done without demolishing it with less weight to strength ratio.
This document presents an experimental and analytical study comparing the structural behavior of composite concrete slabs with profiled steel decking. 18 full-scale slab specimens were tested under different shear span lengths to evaluate the longitudinal shear bond strength between the concrete and steel deck. The experimental results were compared to analytical calculations using the m-k method and partial shear connection method from Eurocode 4. The m-k method was found to provide a more conservative estimate of load-carrying capacity than the partial shear connection method, with generally good agreement between experimental and analytical values.
The document summarizes Ranjit Kumar Sharma's thesis defense on the structural behavior of hybrid and ductal decked bulb T beams prestressed with carbon fiber composite cables (CFCC). The experimental program involved shear and flexural testing of hybrid and ductal beams with varying shear span-to-depth ratios. Research findings showed the beams failed in diagonal shear or flexural compression. Crack patterns and load-deflection responses are presented. The research aims to examine shear behavior without stirrups and evaluate design guidelines for hybrid and ductal beams.
This document reviews research on the bond strength between steel and concrete in concrete-filled steel tubes (CFSTs). It summarizes several studies that investigated factors affecting bond strength like cross-sectional dimensions, steel type, concrete properties, temperature, and interface characteristics. The review finds that 70% of bond strength comes from friction at the interface, while 30% comes from chemical adhesion and mechanical interlocking. It also identifies ways to improve bond strength, such as using expansive concrete, increasing concrete strength, and adding perforations to the steel tube interior.
Effect of width and layers of GFRP strips on deflection of Reinforced Concret...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This study uses explicit finite element analysis to predict the behavior of fiber-reinforced polymer (FRP) composite grid reinforced concrete beams subjected to four-point bending. The finite element models accurately captured the load-deflection behavior observed experimentally. A substructure model was also developed to analyze stresses in the longitudinal reinforcement at failure. This led to a proposed analysis procedure that accounts for different failure modes, providing conservative predictions of load capacity.
This study investigated the compressive strength of reinforced concrete columns wrapped with different hybrid fiber reinforced polymer (FRP) configurations. Four 150x380mm concrete columns were tested: one unconfined control column and three wrapped with different combinations of glass, basalt, and jute FRP. The column wrapped with two layers each of basalt, glass, and jute FRP (CBGJ) achieved the highest compressive strength, reaching 1000kN and exceeding the unconfined column's strength by 25%. Analysis of the load-displacement and load-strain behaviors showed that the CBGJ wrapping configuration resulted in higher displacement and strain values compared to the other specimens. The results indicate that hybrid FRP wrapping can significantly
Recycling of waste materials produced from the construction and demolition
activities is becoming a demand for modern societies willing to achieve environmental
sustainability. To date, the use of crushed concrete aggregate (CCA) in replacement of
natural coarse aggregate to produce high quality concrete is very limited. This can be
attributed to the missing information on the properties of the original concrete before
crushing, the limited data that clarifies the influence of using CCA on the material
properties of the concrete mixture as well as the overall structural behavior of the
reinforced concrete element in which it is used. An experimental testing program has
been conducted on reinforced concrete beams to assess the influence of CCA
replacement ratio on their structural performance and the results have been briefly
discussed in this paper. The primary aim of the study presented herein is to
numerically evaluate the influence of the concrete compressive strength (fcu) and the
shear span to depth ratio (a/d) on the structural performance of reinforced concrete
beams casted with two different concrete mixtures incorporating 0% and 100% CCA.
Accordingly, ten beams have been modelled using ANSYS finite element software with
two control beams being validated with the experimental data. The results
demonstrate the increase of the load carrying capacity and ductility of beams with
100% CCA with increasing the fcu. On the contrary, increasing the shear span to depth
ratio leads to the reduction in the capacity of the beams casted with the two different
concrete materials. As a final conclusion, the results of the performed numerical
analysis designate undesirable structural performance of the concrete beams with
100% CCA. Therefore, it is not recommended to use concrete mixtures with full
Developing A Prediction Model for Tensile Elastic Modulus of Steel Fiber – Ce...IJRESJOURNAL
ABSTRACT: This paper attempts to develop a prediction model that can be used in line with prescribed laboratory experiments for indirect tensile test such that tensile elastic modulus can be predicted for cement stabilized lateritic soil reinforced with steel fiber using measured properties of the material. The results of the tensile elastic modulus obtained from the Derived Prediction Model almost nearly replicates that obtained from calculations from laboratory experimentation. Results obtained revealed that both the predicted values and calculated values have a linear correlation with an R2 of 96.4%. On this basis the Derived Prediction Model can be said to be valid within the limits of the study.
IRJET- Review on Steel Concrete Composite ColumnIRJET Journal
1. The document reviews research on steel-concrete composite columns, where steel columns are infilled with concrete. Wire mesh is welded inside steel columns to improve bond between steel and concrete.
2. Three composite columns and three reinforced concrete columns of the same size were tested and compared. The composite columns showed better structural behavior than reinforced concrete columns in terms of ultimate strength, ductility, energy absorption capacity, and stiffness.
3. The literature review discussed previous research on composite columns that found infilling concrete inside steel tubes improves tensile strength and load capacity compared to hollow steel tubes. Previous studies also showed that composite columns experienced less damage than steel-only columns under the same loads.
1) The document describes an experimental investigation of glass fibre reinforced plastic (GFRP) bridge deck panels subjected to static and fatigue loading.
2) Testing of prototype GFRP composite bridge deck panels was conducted under simulated wheel loads, with two rectangular patch loads applied symmetrically.
3) The results showed that under buckling criteria, panels failed at 123.6 kN with a deflection of 7.538mm, and under local shear criteria panels failed at 113.8 kN with a deflection of 4.057mm. Panels also resisted up to 5 million fatigue cycles.
Strengthening structures via external bonding of advanced fibre reinforced polymer (FRP) composite is becoming very
popular worldwide during the past decade because it provides a more economical and technically superior alternative
to the traditional techniques in many situations as it offers high strength, low weight, corrosion resistance, high fatigue
resistance, easy and rapid installation and minimal change in structural geometry. Although many in-situ RC beams
are continuous in construction, there has been very limited research work in the area of FRP strengthening of continuous
beams.
This document discusses structural rehabilitation of reinforced concrete columns through reinforced concrete jacketing. It assesses different aspects of the jacketing process including anchoring added longitudinal reinforcement, interface surface preparation, spacing of added stirrups, and adding new concrete. Recommendations are provided based on research findings. Proper cleaning of holes drilled in footings is important for anchoring reinforcement. Sandblasting is an effective method for increasing surface roughness at the column-jacket interface. Published research has found that interface treatment may not be necessary for strengthening undamaged columns, but could be important for short columns.
Seismic rehabilitation of beam column joint using gfrp sheets-2002Yara Mouna
The document summarizes a study that tested different rehabilitation techniques for improving the seismic performance of reinforced concrete beam-column joints. Three beam-column joints were tested: a control specimen and two specimens that were rehabilitated using glass fiber-reinforced polymer (GFRP) sheets. The control specimen failed in a brittle shear and bond failure mode, while the rehabilitated specimens exhibited a more ductile flexural failure of the beam. The rehabilitation techniques strengthened the joint shear capacity and prevented bond-slip failures of the beam reinforcement in the joint. A simple design methodology for the GFRP rehabilitation is proposed.
Experimental and numerical study on behavior of externally bonded rc t beams ...IJARIIT
Fiber-reinforced polymer (FRP) application is a very effective way to repair and strengthen structures that have
become structurally weak over their life span. FRP repair systems provide an economically viable alternative to traditional
repair systems and materials. In this study, an experimental investigation on the flexural behavior of RC T-beams
strengthened using glass fiber reinforced polymer (GFRP) sheets are carried out.
Reinforced concrete T beams externally bonded with GFRP sheets were tested to failure using a symmetrical two
point static loading system. Seven RC T-beams were casted for this experimental test. All of them were weak in flexure and
were having same reinforcement detailing. One beam was used as a control beam and six beams were strengthened using
different configurations of glass fiber reinforced polymer (GFRP) sheets. Experimental data on load, deflection and failure
modes of each of the beams were obtained. The effect of different amount and configuration of GFRP on ultimate load
carrying capacity and failure mode of the beams were investigated.
The experimental results show that externally bonded GFRP can increase the flexural capacity of the beam
significantly. In addition, the results indicated that the most effective configuration was the U-wrap GFRP.A series of
comparative studies on deflection between the present experimental data and results from finite element method and IS code
method were made. A future area of research are being outlined.
This document provides a summary of research on the fatigue behavior of steel structures strengthened with fiber-reinforced polymer composites. It discusses various failure modes that can occur, including adhesive failure, delamination of composites, and debonding at interfaces. The document also reviews studies on how fiber-reinforced polymer composites can improve the fatigue resistance and life of steel structures by reducing crack propagation rates and increasing load capacities. It finds that fiber-reinforced polymer jacketing is effective at confining local buckling in compression members and arresting crack growth in steel beams and plates under cyclic loading conditions.
Experimental study on flexural behavior of the self compacting concrete with ...IAEME Publication
This document summarizes an experimental study on the flexural behavior of self-compacting concrete with hybrid fibers. Tests were conducted to evaluate the compressive and flexural strength of self-compacting concrete mixtures containing different fiber combinations. Nylon e-300 microfibers and Nylon tuff macrofibers were added to self-compacting concrete mixtures in various volumes. The results showed that adding hybrid fibers improved the compressive and flexural strength properties of self-compacting concrete compared to plain self-compacting concrete.
The Primrose East Bridge project utilized new technologies including a geosynthetic reinforced soil (GRS) integrated abutment, folded plate girders, and ultra-high performance concrete (UHPC). The bridge was constructed off-site and elements were delivered and installed, accelerating construction. The GRS abutment provided rapid construction without need for cranes or piles. Folded plate girders developed at UNL were lightweight. UHPC with over 21,000 psi compressive strength resulted in narrow joints and minimal shrinkage. The project was completed and opened to traffic ahead of schedule in November.
The document summarizes several projects undertaken by the HPC Lab, including developing software and algorithms for graph analysis on emerging platforms (CASS-MT), genome assembly (GALAXY), and RNA structure prediction (GTFold). It also mentions projects involving graph benchmarks (Graph500), dynamic graph packages for Intel platforms (STING), and phylogenetics research on the IBM Blue Waters supercomputer (PetaApps).
This document summarizes the results of a study on the shrinkage behavior of ultra high performance concrete (UHPC) at the manufacturing stage. Key findings include:
1) UHPC experiences significant autogenous and drying shrinkage that can lead to cracking without proper measures.
2) Mix designs and material properties tested included water-to-binder ratio, cement content, silica fume, and steel fibers.
3) Tests measured mechanical properties, setting behavior, autogenous shrinkage, free shrinkage under different exposure conditions, and restrained shrinkage using a ring test setup.
4) Results showed the combined use of a shrinkage reducing agent and expansive admixture reduced free and rest
A brief overview on Non conventional concrete technologies like Self compacting concrete,Green concrete etc.
A good topic for technical presentation on Civil Engg.
The document discusses Reactive Powder Concrete (RPC), which was developed in France in the early 1990s. The first RPC structure was the Sherbrooke Bridge in Canada erected in 1997. RPC is composed of very fine powders, steel fibers, and superplasticizer that gives it ultra-high strength and durability ranging from 200 to 800 MPa. Some applications of RPC include bridges and structures requiring light, thin components or extra safety.
Seven Wonders of Concrete: Vote for your favourite projectLafarge
Lafarge is a partner of the France Pavilion at the Shanghai 2010 World Expo. The Expo is focusing on themes of urbanization, architecture and sustainable construction. The "Seven Wonders of Concrete" presentation illustrates the most spectacular technological initiatives in terms of building materials through symbolic structures. From June 7th, come and vote on our Facebook page for your favorite structure. The structure which wins the most likes will be named Top Wonder of Concrete!
- Ultra-high performance concretes (UHPCs) have exceeded performance frontiers and demonstrated advantages through numerous projects, validating their capabilities. However, they require a technical and legal framework tailored to their growing use and diverse applications.
- Standardization work is now in progress to develop an official UHPC standard, which will improve insurability by providing recognized reference systems. This includes standards for UHPC materials, calculation methods, and implementation. A draft material standard is expected in 2014.
- The objective of the standard is to facilitate UHPC specification and acceptance by authorities. It will provide a guaranty and insurability to reassure project managers by establishing a quality framework for technical and economic approaches. The standard
Select UHPC products and projects from around the world. Ultra High Performance Concrete is being utilized for structural applications and fine furnishings in residential and commercial applications.
This presentation material is concerned with research results for Ultra High Performance Concrete. The research was focused on the behavior of shrinkage in UHPC.
BlingCrete is a textile-reinforced concrete with a light-reflecting surface whose specific properties and smart manufacturing processes offer a wide variety of applications. In addition to being light-reflecting, this material non-flammable. BlingCrete is based on system precast building methods.
After viewing this program, you will be able to:
• Identify the difference between precast/pre-stressed concrete and tilt up concrete structures
• Explain the benefits of using tilt up concrete
• Discuss the design considerations for tilt up concrete structures
• BIM into precast / Tilt up concrete
FLEXURAL PROPERTIES OF HYBRID FIBRE REINFORCED CONCRETE - A COMPARATIVE EXPER...Journal For Research
Fiber-reinforced concrete (FRC) is concrete containing fibrous material which increases its structural integrity. It contains short discrete fibers that are uniformly distributed and randomly oriented. The most important advantages are hindrance of macro-cracks’ development, delay in micro-cracks’ propagation to macroscopic level. In this project the flexural properties were studied for concrete prepared using different hybrid fibre combinations of glass fibres and polypropylene fibres. The volume fraction of the glass fibres and polypropylene fibres used in this study are 0.4% and 0.5% of total volume of concrete. The flexural properties were studied using centre point loading method on beam specimens. The objective of this study is to evaluate flexural strength of fibre reinforced concrete with respect to different combination of glass fibres and polypropylene fibres. It is observed that quantity of fibres both glass fibres and polypropylene fibres play significant role in increment flexural properties of concrete.
A UHPC (ultra high performance concrete) presentation projects.Nolan Mayrhofer
UHPC presentation featuring select international Ductal projects. This is an in depth look at the types of architectural projects UHPC is best suited for.
Fiber reinforced concrete (FRC) is concrete containing fibrous material which increases its structural integrity. This document discusses FRC, including its history, types of fibers used, applications, and mechanical properties. It also provides a case study comparing the effects of straight and hooked steel fibers on properties like workability, strength, and toughness. The study found that hooked fibers had better dispersion and increased flexural strength, toughness, and energy absorption compared to straight fibers. In conclusion, the document provides a detailed overview of FRC and how fiber type and content can influence its mechanical behavior.
This document discusses ultra-high performance concrete (UHPC) and its properties and production methods. It describes the materials used in UHPC including cement, silica fume, quartz fines, fine aggregates, and steel fibers. The mixing and curing processes are also outlined. UHPC is shown to have high compressive strength over 150MPa, low permeability, and excellent durability. Its residual flexural tensile strength allows it to be used without conventional reinforcement. While UHPC has great benefits, its high cost currently limits its widespread use. Special applications like precast elements and manhole covers show promise to help reduce costs. Proper mix design and material quality control are needed to achieve UHPC's outstanding mechanical and
Cements in Nebraska: NDOR Research Into FlyAsh AlternativesJill Reeves
This document summarizes information about cements used in Nebraska. It discusses that cements are made from crushed rock like limestone, shale and iron ore that are heated to high temperatures. It then explains that changes in emission standards in the late 1970s-1980s resulted in changes to cements' alkali content, which increased instances of alkali-silica reaction (ASR) in concrete. The document reviews how Nebraska investigated this and now requires cements to meet specific chemical ratios to mitigate ASR. It outlines current specifications that allow various cement blends with supplementary cementitious materials like fly ash or slag to control the calcium to silica ratio and prevent ASR issues.
This document discusses an ultra-high performance concrete called UHPC. UHPC has compressive strengths over 20,000 psi, is more ductile and durable than regular concrete, and allows for thinner lighter structures. The document provides details on UHPC's composition and properties compared to regular concrete. It also showcases numerous architecture projects around the world that have used UHPC in innovative ways to create distinctive designs not possible with regular concrete.
Prefabrication : challenges and opportunities for the contractorBenoit Parmentier
The document discusses prefabrication in construction, including current challenges and future opportunities. It covers:
1. The context of needing more cost-efficient, high-performing buildings.
2. Current prefab systems using various materials and construction methods, and their general benefits like quality, speed, environmental impact.
3. Moving towards more integrated prefab systems to aid the energy transition and meet renovation needs, through innovations like BIM, geothermal energy piles, and concrete activation.
4. The push to renovate existing building stock, and how prefab techniques may help with renovation projects.
5. Potential future directions, like innovative materials, fully integrated modular structures,
Shear and flexural behavior of ferro cement deep beamseSAT Journals
Abstract
The recent application of Ferro cement includes prefabricated roofs elements, load bearing panels, bridge decks and others. However
there have been many structural applications in different parts of the world especially in eastern hemisphere considerable efforts have
been made by many individuals and research organization around the world to study the engineering of Ferro-cement. This present
study deals with the behavior of Ferro cement deep beams under central point load. A total of 27 rectangular deep beams have been
casted of dimension 125 x 250mm and the lengths of beams have been varied along with the variation of wire mesh and mortar
strength. Before testing, the top surfaces of these beams were white washed, to get a clear picture of crack pattern. Along with these
beams 27 cubes have been casted with the dimensions 7.06 cm x 7.06 cm x 7.06 cm. the compressive strength of mortar is determined.
Keywords: Admixture, Deep Beams, Ferro cement, Shear Span.
Experimental and Numerical Study on Full-Scale Precast SFRC PipesNedal Mohamed
This thesis investigates the use of steel fibres as reinforcement in precast concrete pipes through experimental and numerical studies. Full-scale steel fibre reinforced concrete (SFRC) pipes with diameters of 300, 450, and 600 mm were fabricated and tested under three-edge bearing loading. The mechanical properties and flexural performance of dry-cast SFRC were characterized. Testing results showed that SFRC pipes achieved the required strength class at lower fibre dosages than conventional steel cage reinforced concrete pipes. Numerical modeling was able to predict the structural behavior and ultimate load capacity of SFRC pipes. The findings provide guidance for the design and production of economical precast SFRC pipes without welded steel cages.
Utilization of steel in construction of high performance structures: A ReviewIRJET Journal
This document provides a literature review of research papers related to the analysis of steel structures using different alloys and metals in steel trusses. It summarizes several research papers that studied topics like cold-formed steel, steel beam-column connections, steel truss behavior, and comparisons of steel, concrete and cold-formed steel structures. The research papers used analytical and experimental methods to analyze structural behavior and load-carrying capacity. The results showed that cold-formed steel can provide economic and construction time benefits for buildings compared to other materials.
IRJET- Behavior of RC T-Beam Strengthen using Basalt Fiber Reinforced Pol...IRJET Journal
This document describes an experimental study on strengthening reinforced concrete T-beams using basalt fiber reinforced polymer (BFRP) sheets. Seven T-beams were cast, with one control beam and six strengthened beams. The strengthened beams were reinforced with varying configurations and layers of BFRP sheets. Testing was conducted to failure under static loading. The results showed that externally bonded BFRP significantly increased the flexural capacity of the beams. U-wrap configuration with BFRP was found to be the most effective strengthening method. Data on load, deflection, and failure modes was collected and analyzed to evaluate the effect of different BFRP configurations on structural performance.
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
This document summarizes an experimental study that tested circular concrete-filled steel tube columns with varying parameters. 45 specimens were tested with different fiber percentages (0-2%), tube diameter-to-wall-thickness ratios (D/t from 15-25), and length-to-diameter (L/d) ratios (from 2.97-7.04). The results found that columns filled with fiber-reinforced concrete exhibited higher stiffness, equal ductility, and enhanced energy absorption compared to those filled with plain concrete. The load carrying capacity increased with fiber content up to 1.5% but not at 2.0%. The analytical predictions of failure load closely matched the experimental values.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
Abstract
This paper presents an outlook on experimental behavior and a comparison with predicted formula on the behaviour of circular
concentrically loaded self-consolidating fibre reinforced concrete filled steel tube columns (HSSCFRC). Forty-five specimens were
tested. The main parameters varied in the tests are: (1) percentage of fiber (2) tube diameter or width to wall thickness ratio (D/t
from 15 to 25) (3) L/d ratio from 2.97 to 7.04 the results from these predictions were compared with the experimental data. The
experimental results) were also validated in this study.
Keywords: Self-compacting concrete; Concrete-filled steel tube; axial load behavior; Ultimate capacity.
Comparative Analysis and Design of Voided Slab and RCC I Girder with Solid Sl...ijtsrd
This thesis is basically based on the comparison of the use of voided slab, RCC Solid slab and RCC Girder. In this study analysis and cost comparison of RCC Solid slab deck, RCC Voided slab deck and RCC Girder is done for superstructure spanning 20 m length. Solid slabs having greater span are uneconomical due to heavy dead load of concrete. To make it economical longitudinal beams are provided for spans greater than 10.0 m. Reinforced Concrete Girder is generally adopted for a fly over or road bridge, but in case of a river bridge with submersible superstructure, the longitudinal beams creates obstruction to the flow of water and results in additional stresses in cross direction on beams. To reduce the self weight of concrete without sacrificing its flexural strength, in solid slab voids are incorporated in concrete section. This technic offers many advantages over a conventional solid concrete slab like reduced material use, lower total cost of construction, and increased structural efficiency. This report also shows that the dead load of bridge superstructure can be reduced by providing voids in concrete where it is unnecessarily provided. Presence of voids within the concrete structure makes analysis of structure very complicated. The analysis of RCC Solid slab, RCC Girder and RCC voided slab deck for various loads as specified in IRC is done using staad pro software for span length of 20 m and width of 15.10 m. The analysis illustrates the behavior of bending moments, Shear Force, displacements, reactions for various load conditions. It is concluded that use of voided slab is more feasible for 20 m length and 15.10 m width. It is also economical as compared to solid slab and Reinforced concrete Girder. Kunal Songra | M. C. Paliwal "Comparative Analysis and Design of Voided Slab and RCC I Girder with Solid Slab in Bridge Structure" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-6 , October 2021, URL: https://www.ijtsrd.com/papers/ijtsrd47679.pdf Paper URL : https://www.ijtsrd.com/engineering/civil-engineering/47679/comparative-analysis-and-design-of-voided-slab-and-rcc-i-girder-with-solid-slab-in-bridge-structure/kunal-songra
Beam column joints in concrete framed structure have been identified as critical member for transferring forces and bending moments between beams and columns. The change of moments in beam and columns across the joint region, under loadings, induces high shear force and stresses as compared with other adjacent members. The shear failure caused is often brittle in nature which is not an acceptable structural performance. Retrofitting enhances the moment carrying capacity of joint. Often beam column joints need to be strengthened. Author proposes use of ferrocement for retrofitting as wrapping technique, cost effective alternative to costly FRP wrapping technique. In this present research study, modelling & comparison of Beam-Column joint with and without ferrocement jacket is carried out by finite element method using software ANSYS APDL. The comparison shows enhanced performance of the jacketed model over Non jacketed in terms of stresses, ultimate load carrying capacity.
1. The document discusses strengthening of reinforced concrete (RC) beams with externally bonded glass fiber reinforced polymers (GFRPs).
2. Shear failure of RC beams is identified as a disastrous failure mode, and GFRP composites have become a popular technique for shear strengthening due to advantages like high strength and corrosion resistance.
3. The document reviews several studies that have examined using GFRP wraps, strips, and grids for shear strengthening RC beams, finding they can increase shear capacity significantly.
Effect of Wire Mesh Orientation on Strength of Beams Retrofitted using Ferroc...CSCJournals
The document discusses an experimental study on the effect of wire mesh orientation in ferrocement jackets used to retrofit under-reinforced concrete beams. Eight prototype beams were tested, with two control beams and six beams stressed to 75% of the control capacity and then retrofitted. Ferrocement jackets with wire mesh at 0, 45, and 60 degrees were used. Testing found load capacity increased 45.87-52.29% for retrofitted beams. Beams with 45 degree wire mesh showed the highest increase in energy absorption, followed by 60 and 0 degrees. Ductility increased most for 0 degree wire mesh retrofitted beams. The 45 degree orientation provided the best balance of increased load capacity and energy absorption.
IRJET- An Experimental Study on Strengthening of RCC Beam using Waste PVC Fle...IRJET Journal
The document presents the results of an experimental study that tested reinforced concrete (RCC) beams strengthened with different materials to increase their flexural strength. 12 RCC beams were prepared and tested under flexure. Some beams were wrapped with waste PVC flex banners, some were wrapped with chicken mesh and flex banners, and some were wrapped with weld mesh and flex banners. The materials were bonded to the beams using different adhesives. It was found that beams wrapped with just flex banners saw a 6% increase in load capacity. Beams with chicken mesh and flex banners saw a 21% increase. Beams with weld mesh and flex banners saw the greatest increase of 147%. The study showed that commonly available waste materials can significantly
The document reviews different techniques for retrofitting reinforced concrete beams, including bonding steel plates, fiber reinforced polymer sheets, and carbon fiber wrapping. Bonding steel plates was an early technique but had issues with debonding and corrosion. Fiber reinforced polymer sheets provide increased strength without corrosion risks, though delamination was also a problem. Recent techniques have focused on improving anchorage of retrofit materials to address debonding and delamination issues, with promising results in significantly increasing beam strength.
Analysis of Deck Bridge with Pre Stress Deck Bridge under IRC Loading Conditi...ijtsrd
A bridge deck is the portion of a bridge that acts as the roadway in the support of vehicular or pedestrian traffic. While deck parts like trusses, girders, rails, arches, posts and cantilevers assume a number of forms and types, there are relatively few bridge deck types given the utilitarian nature of the component. Deck types are defined by the materials from which they are made and the manner in which those materials are fit together. Yogesh Kanathe | Nitesh Kushwaha "Analysis of Deck Bridge with Pre-Stress Deck Bridge under IRC Loading Conditions a Review" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-6 , October 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29636.pdf
https://www.ijtsrd.com/engineering/civil-engineering/29636/analysis-of-deck-bridge-with-pre-stress-deck-bridge-under-irc-loading-conditions-a-review/yogesh-kanathe
COMPARATIVE STUDY ON RETEROFITTING OF RCC BEAM AND COLUMN JOINT BY USING FERR...IRJET Journal
This document summarizes research on retrofitting reinforced concrete beam-column joints using ferrocement, glass fiber reinforced polymer (GFRP), and carbon fiber reinforced polymer (CFRP). It presents the methodology, results, and conclusions of finite element modeling conducted using ANSYS. The modeling analyzed exterior beam-column joints under different retrofitting conditions: without retrofitting, with ferrocement, with GFRP, and with CFRP. The results showed that retrofitted joints had 30% higher load carrying capacity and improved load-deformation behavior compared to unretrofitted joints. Specifically, CFRP retrofitting shifted the failure from the column to the beam, preventing progressive collapse. In conclusion, fiber-reinforced polymer
In the last ten years or a little more, CFRP strips and fabrics have been successfully externally bonded to rehabilitate the concrete structures. Most of the previous research focused on the use of CFRP as an enhanced material to improve flexural, shear, ductility and ductility behaviour and confinement of concrete structural members, while limited attention was paid to the investigation of strengthened reinforced concrete (RC) members against torsion, particularly continuous concrete beams. This study aims to detect experimentally the CFRP strengthening technique for continuous RC beams exposed to pure torsion. The experimental program includes investigation of two groups of beams; the first group was composed of twelve un-strengthened beam specimens and the second one includes a total of twelve strengthened beam specimens; all were experienced under pure torsion. Factors considered in the testing program included the effects of concrete compressive strength and the angel of a twist. The angle of twist at each level of force applications, torque at first crack, ultimate torque was to be in comparison with for control and strengthened beams. The outcomes of the tests indicated that all beams wrapped with CFRP fabrics resulted in improvement in tensional resistance as compared with the reference specimens.
Behavior Of Reinforce Fibrous Self Compacting Concrete Beam Strengthening Wit...IJMER
In recent years, self-compacting concrete (SCC) has gained wide use for placement in
congested reinforced concrete structures with difficult casting conditions. SCC offers several
economical and technical benefits; the use of fibers extends its possibilities. Adjustment of the
water/cement ratio and super plasticizer dosage is one of the main key properties in proportioning of
SCC mixtures. Several tests such as slump flow, V-funnel, L-box were carried out to determine
optimum parameters for the self-compatibility of mixtures. In this article Nylon 300-e3 micro synthetic
fiber and Nylon Tuff macro synthetic fiber has used in combination and the effect of fiber inclusion on
the compatibility of hybrid fiber reinforcement concrete are studied. Both the Nylon fiber hybrid with
SSC and compared to Plan SSC, Hybrid SSC. The behavior of Reinforced Concrete (RC) beams
strengthened in flexure by means of different combinations of externally bonded hybrid Glass and
Carbon Fiber Reinforced Polymer (GFRP/CFRP) sheets has also studied.
The document summarizes an experimental study on using carbon fiber reinforced polymer (CFRP) sheets to rehabilitate and strengthen reinforced concrete beams. Twelve beams were fabricated and strengthened with different CFRP configurations. Beams were loaded to different magnitudes prior to strengthening to study the effect of initial loading. Beams were then retrofitted with one or two CFRP layers and reloaded until failure. Results showed shear strength increased significantly with CFRP sheets. Orienting the sheets at 45 degrees was most effective. The literature review discussed previous research on using CFRP to strengthen beams in flexure and shear. Parameters like CFRP amount and configuration affected failure modes and structural performance.
Similar to Structural Behavior of Hybrid & Ductal Decked Bulb T Beams Prestressed with CFCC (20)
This certificate certifies that R. Sharma participated in a seminar on April 7, 2015 called "RedBuilt – Engineered Wood Products" held by Dave Koons, a RedBuilt Technical Representative. The seminar was worth 1.0 hours of professional development credit.
Ranjit Sharma received a Certificate of Completion for successfully completing a 1-hour Design Seminar on the proper design and application of advanced composites for strengthening structures. The seminar was presented by Julie Mizzi on March 10, 2015 at 6765 Daly Rd., West Bloomfield, MI 48322. The certificate was certified by Rhiannon Westerkamp.
Ranjit Sharma attended a seminar presented by Matthew Brady on March 8, 2016 in West Bloomfield, MI about innovations in steel. The seminar demonstrated how recent innovations in steel allow for more efficient design concepts and overcome concerns about floor heights and spans. Examples of framing systems that achieve low floor-to-floor heights and long spans economically were discussed. Attendees also learned about steel manufacturing processes, current market conditions, and how steel relates to sustainability. The seminar covered how innovations in fabrication equipment and delivery processes using BIM can benefit project costs and schedules.
Ranjit Sharma attended a training course on strength design anchorages to concrete with post-installed adhesive anchors held in West Bloomfield Twp, MI on 3/24/2015. The course provided 1 PDH credit, which is equivalent to 1 contact hour.
2. ii
ABSTRACT
Based on the current infrastructure conditions and performance, the American Society of Civil
Engineers (ASCE) has rated the United States bridges with a mediocre Grade Point Average
(GPA) of C+
in the scale of A to F according to their recent 2013 America’s infrastructure report
card (ASCE 2013). The United States so far has 607,380 bridges, out of which 66,749 bridges are
structurally deficient and 84,748 bridges are functionally obsolete, i.e. one in every nine bridges
is deficient and requires immediate rehabilitation. An estimated Federal Highway Administration
(FHWA) report (ASCE 2013) indicates, United States needs $20.5 billion annually for the next
fifteen years in order to eliminate the present deficient backlog. However, the nation currently
receives only $12.8 billion annually to mitigate deficient bridges (ASCE 2013). The primary
reasons behind the deterioration of prestressed concrete bridges as per Precast/Prestressed
Concrete Institute (PCI) reports (2004) are; a) increase in the volume of traffic, b) low durability
of conventional concrete, and, c) corrosion of steel reinforcement. Bridges made of side-by-side
box beam do not provide any space between the beams for visual inspection of any progressive
damage and maintenance of critical elements, which increases the risk of bridge failure. In
addition, conventional precast bridge system consumes excessive onsite time for the preparation
and construction of cast-in-place deck system that disrupts the flow of traffic.
To address the present issues in the bridge industry, several engineers have discovered numerous
innovative materials and novel construction techniques as an alternative solution to enhance
service life span of prestressed concrete bridges. The most significant breakthrough in the field of
concrete technology based on strength is the development of Ultra High Performance Concrete
(UHPC) and Fiber Reinforced Polymer (FRP). Both of these are the latest innovative material in
the field of construction and have gained the popularity across the globe due to their outstanding
characteristic properties of superior strength, excellent durability and long-term stability.
However, in reality, these innovative materials has a very limited number of applications, mostly
due to their high unit rate of production in comparison with locally available inexpensive
traditional construction material. Therefore, it is of utmost importance to initiate a research
investigation to increase the applications of these innovative materials by exploiting their superior
characteristic properties in an optimized structure.
3. iii
The research study presented in this thesis introduces state-of-the-art long lasting corrosion-free
decked bulb T-beams constructed from UHPC and prestressed with CFCC strands. These beams
anticipate to a) reduce the construction cost of bridge girders employing UHPC and FRP by
introducing the concept of hybridization and optimization without compromising their structural
behavior, b) eliminate the use of transverse reinforcement both in the critical shear span or in the
entire span of the beam, c) mitigates sudden shear and flexural failure of FRP prestressed bridge
girders employing conventional concrete and reinforcement, d) accelerate onsite construction of
bridges with inbuilt deck, e) reduces overall bridge maintenance cost by using corrosion-free
CFCC strands, and, f) reduces the risk of bridge failure by providing space between the beams for
visual inspection of critical elements. The two types of beams proposed in this present
investigation are: hybrid beam and ductal beams. The hybrid beam brings the concept of hybrid
formulation between two different types of concrete i.e. UHPC as fiber reinforced concrete in a
dense cementitious packed mix and High Strength Concrete (HSC) as conventional concrete with
minimum 28th
day average compressive strength of 9,000 psi (62.05 MPa) at different zones/spans
along the length of the beam to mitigate potential sudden shear failure by increasing inelastic
energy absorption and shear capacity of the beam. The hybrid beam was constructed by placing
UHPC without stirrups in the shear span of the beam at both ends which are critical to the shear
stresses. Whereas, the middle span of the beam which is critical for flexure was constructed with
HSC with stirrups. On the other hand, the ductal beam brings the concept of section optimization
of full UHPC beam section and suggests an under-reinforced FRP prestressed UHPC beam section
as an alternative approach to mitigating potential sudden flexural failure of under-reinforced FRP
prestressed HSC beam. Further, in order to investigate the structural performance of both the
hybrid and ductal beams, a comprehensive experimental program was conducted under varying
load configuration to evaluate shear and flexural behavior. Four shear load mechanisms with shear
span-to-depth (a/d) ratios of 3.0, 4.0, 5.0 and 6.0 were investigated on four end span of two hybrid
beams while two shear load mechanisms of a/d ratios of 3.0 and 4.0 were conducted on two end
span of one ductal beam. Also, both hybrid and ductal beam mid spans were tested under four-
point bending. The behavior of each test beam was evaluated experimentally in terms of deflection,
strain in concrete, strain in the CFCC prestressed strands, ductility ratio, crack patterns, crack
width, cracking force, ultimate failure load and the mode of shear and flexural failure. Further, the
experimental results of the test beams were compared with the experimental results of a similarly
4. iv
reinforced HSC beams investigated by Rout (2013) and Grace et al. (2015) under similar load
configurations. This facilitated a comparative assessment on the structural performance of these
beams under shear and flexural load. In addition, a comparative study was carried out between the
results obtained through the experimental investigation and analytical methods using applicable
design guidelines and codes for UHPC.
The outcomes of research investigations showed that UHPC is efficient in replacing shear
reinforcement in simply supported CFCC prestressed HSC beams. The UHPC can be utilized to
replace shear reinforcement either partially or completely throughout the span without
compromising the structural behavior as exhibited by similarly reinforced HSC beams with
traditional shear reinforcement. In addition, the behavior of all the test beams outperform by
exhibiting similar or higher ductility, resistance to cracking, ultimate shear and flexural capacity.
Further, with the increase in a/d ratio, UHPC present in the critical shear span of the hybrid beams
attributed to changing the catastrophic mode of shear failure to a more ductile shear/flexural mode
of failure. Whereas, the Rout’s (2013) HSC beams exhibited same catastrophic shear failure
irrespective of a/d ratio.
Further, upon comparison of experimental results of all test beams with analytical predicted values,
it was observed that French code AFGC (2002) and Japanese code JSCE (2006) provided similar
shear capacity. In addition, an analytical calculation developed in the present research
investigation to predict the flexural capacity and the behavior of the ductal beam slightly
overestimated the flexural capacity and the behavior.
Therefore, the decked bulb T-beam constructed with UHPC and prestressed with CFCC as
investigated in the present study promises a viable solution to mitigate potential sudden shear and
flexural failure of HSC beams prestressed with CFCC. This is achieved by eliminating shear
reinforcement either partially or completely throughout the span without compromising overall
structural performance. In addition, the hybrid and the ductal decked bulb T-beams exploits the
superior properties of UHPC and CFCC material by optimizing and hybridizing the section which
in turn reduces the higher initial cost of constructing bridges employing these materials.
5. v
STRUCTURAL BEHAVIOR OF HYBRID & DUCTAL DECKED BULB T-BEAMS
PRESTRESSED WITH CARBON FIBER COMPOSITE CABLES
Ranjit Kumar Sharma
Advisor: Nabil F. Grace, Ph.D., P.E.
University Distinguished Professor,
Dean, College of Engineering,
Director of Center for Innovative Material Research (CIMR),
Lawrence Technological University, Southfield, U.S.A.
Date
6. vi
DEDICATION
I dedicate this thesis to my mother Sonmati Devi for giving me life and my
friend Gayatree Rath as a source of inspiration.
7. vii
ACKNOWLEDGEMENTS
I would like to express my earnest thanks to Dr. Nabil F. Grace, Dean of Engineering,
University Distinguished Professor, and Director, Center for Innovative Materials Research
(CIMR) at Lawrence Technological University (LTU). His guidance, encouragement, vision, and
innovative thinking have always been a constant source of inspiration for me in my studies.
I am greatly indebted to Dr. Mena Bebawy, Research Scientist, and Adjunct Professor,
LTU, for his technical help and persistence. His assistance and constructive criticism did help in
shaping this thesis. Also, I would like to convey my special thanks to all my instructors and faculty
members at LTU, for making me understand the intricacies of civil engineering in a much easier
manner.
Special thanks go to all the previous researchers here at CIMR, LTU, Prince Baah,
Soubhagya K. Rout and Marc Kasabasic for their excellent and outstanding research commitment
towards the development of decked bulb T-beam bridge system. The present research investigation
considered their experimental finding and took it a step forward towards the development of the
innovative decked bulb T-beam bridge system.
All the experimental work was performed at Structural Testing Center (STC) and CIMR,
LTU. I would like to acknowledge for the facilities provided by the testing center. I also sincerely
thank the U.S. Department of Transportation, Tokyo Rope Mfg. Co. Ltd., Japan, and Lafarge North
America for providing Ultra High Performance Concrete (UHPC) for providing the required fund
and materials to conclude this research.
I would take this opportunity to convey my sincere thanks to all my colleagues at LTU,
Ephrem Kassahun Zegeye, Charles Elder, Neil Waraksa, Brittany Schuel, Shane Hansen, Jordan
Britz, Craig Przytulski, Alan Killeward, Samuel Adjei, Abinash Acharya, Hassan Ernest Razak,
Kathy Gilman, Bridgett Bailiff, and Tamara Botzen for their help and support during my research
investigation. Finally, I would like to thank my parents and friends for their love and support during
all the stages of my life. I would like to express my sincere appreciation towards my father, for his
infinite sacrifices and prayers throughout my life.
8. viii
TABLE OF CONTENTS
ABSTRACT.................................................................................................................................... ii
DEDICATION............................................................................................................................... vi
ACKNOWLEDGEMENTS.......................................................................................................... vii
TABLE OF CONTENTS.............................................................................................................viii
LIST OF FIGURES ...................................................................................................................xviii
LIST OF TABLES..................................................................................................................... xxiv
CHAPTER 1 INTRODUCTION.................................................................................................... 1
1.1 Statement of the Problem...................................................................................................... 1
1.2 Hybrid and Ductal Precast Prestressed Decked Bulb T-Beams............................................ 3
1.3 Motivation............................................................................................................................. 5
1.4 Research Significance........................................................................................................... 6
1.5 Research Objectives.............................................................................................................. 8
1.6 Scope of Work ...................................................................................................................... 8
1.7 Thesis Outline....................................................................................................................... 9
CHAPTER 2 LITERATURE REVIEW ....................................................................................... 10
2.1 Introduction......................................................................................................................... 10
2.2 Available Innovative Materials for Prestressed Bridge Girders ......................................... 11
2.2.1 Concretes.................................................................................................................. 11
2.2.1.1 Ultra High Performance Concrete (UHPC).............................................. 12
2.2.1.1.1 Types of UHPC and mix design ................................................ 12
2.2.1.1.2 Composition of UHPC............................................................... 14
2.2.1.1.3 Fiber Reinforcement .................................................................. 15
2.2.1.1.4 Mixing of UHPC........................................................................ 15
2.2.1.1.5 Placement of UHPC................................................................... 16
9. ix
2.2.1.1.6 Curing of UHPC ........................................................................ 18
2.2.1.1.7 Material Properties of UHPC..................................................... 18
2.2.1.1.8 Corrosion of steel fibers in UHPC............................................. 19
2.2.1.1.9 Cost of UHPC Production.......................................................... 20
2.2.2 Reinforcement.......................................................................................................... 20
2.2.2.1 Fiber Reinforced Polymers (FRPs)........................................................... 22
2.2.2.1.1 Carbon Fiber Composite Cable (CFCC).................................... 22
2.2.3 Application of UHPC............................................................................................... 23
2.2.4 Application of FRPs................................................................................................. 24
2.3 Bond Strength of Ultra High Performance Concrete (UHPC)............................................ 25
2.3.1 Bond strength between UHPC and conventional concretes .................................... 26
2.3.2 Bond strength between UHPC and reinforcement................................................... 27
2.4 Structural Behavior of FRP Prestressed Bridge Girders..................................................... 28
2.4.1 Flexural Behavior of FRP prestressed Bridge Girders ............................................ 29
2.4.1.1 Factors affecting flexural failure of FRP prestressed concrete beam ....... 30
2.4.1.1.1 Ductility or Energy Absorption in FRP Prestressed Concrete
Beams........................................................................................................ 30
2.4.1.2 Previous Research on Flexural Performance of Prestressed Concrete
Beams.................................................................................................................... 33
2.4.1.2.1 Previous Research on Flexural Performance of FRP Prestressed
Concrete Beams ........................................................................................ 33
2.4.1.2.2 Previous Research on Flexural Performance of Prestressed
UHPC Beams............................................................................................ 35
2.4.2 Shear Behavior of FRP prestressed Bridge Girders................................................. 37
2.4.2.1 Background of shear stress in concrete beam........................................... 38
2.4.2.2 Shear Transfer mechanism in a concrete beams....................................... 40
10. x
2.4.2.3 Factors Affecting Shear Failure................................................................ 41
2.4.2.3.1 Shear Span-to-Depth Ratio ........................................................ 41
2.4.2.3.2 Size Effect.................................................................................. 42
2.4.2.3.3 Concrete Strength....................................................................... 44
2.4.2.3.4 Shear Reinforcement.................................................................. 44
2.4.2.3.5 Longitudinal Reinforcement ...................................................... 46
2.4.2.3.6 Effect of Prestressing Force....................................................... 47
2.4.2.3.7 Effect of Openings in the Web................................................... 47
2.4.2.3.8 Loading Conditions.................................................................... 48
2.4.2.4 Shear cracking and failure of prestressed concrete beams........................ 48
2.4.2.4.1 Diagonal Tension Failure........................................................... 49
2.4.2.4.2 Shear Compression Failure........................................................ 49
2.4.2.4.3 Web Crushing Failure................................................................ 50
2.4.2.4.4 Shear Tension Failure ................................................................ 51
2.4.2.5 Previous Research on Shear Performance of Prestressed Concrete Beams
............................................................................................................................... 51
2.4.2.5.1 Previous Research on Shear Performance of Prestressed Concrete
Beams with Stirrups.................................................................................. 51
2.4.2.6 Previous Research on Shear Performance of Prestressed UHPC Beams . 56
2.5 Summary............................................................................................................................. 57
CHAPTER 3 AVAILABLE DESIGN GUIDELINES FOR UHPC ............................................ 58
3.1 Introduction......................................................................................................................... 58
3.2 Material Behavior of Concrete............................................................................................ 59
3.2.1 Stress-Strain Behavior of Conventional Concrete................................................... 59
3.2.1.1 ACI 318/AASHTO Model........................................................................ 59
3.2.2 Stress-Strain Behavior of Ultra High Performance Concrete (UHPC).................... 61
11. xi
3.2.2.1 French Model developed by AFGC and Setra.......................................... 61
3.2.2.2 Australian Model developed by Gowripalan and Gilbert (2000) ............. 64
3.2.2.3 US Federal Highway Administration (FHWA) Models........................... 65
3.2.2.4 Stress–Strain Behavior of UHPC by Vande Voort et al. (2008)............... 66
3.2.2.5 Comparison of stress-strain models.......................................................... 67
3.3 Flexural Analysis and Design of UHPC Section................................................................ 68
3.3.1 Flexural Analysis and Design of Non-Prestressed UHPC Beams........................... 69
3.3.2 Flexural Analysis and Design of Prestressed UHPC Beams ................................... 71
3.3.2.1 Nawy’s Model (2008)............................................................................... 71
3.3.2.2 Garcia’s Model (2007).............................................................................. 72
3.4 Shear Design of UHPC Section.......................................................................................... 75
3.4.1 Shear Design according to AFGC and Setra............................................................ 76
3.4.2 Shear Design according to JSCE ............................................................................. 78
3.4.3 Shear Design According to Australian Guidelines .................................................. 81
3.4.4 Shear Design Recommended by Graybeal (2006)................................................... 83
CHAPTER 4 EXPERIMENTAL PROGRAM............................................................................. 85
4.1 Introduction......................................................................................................................... 85
4.2 Design Concept and Beam Detail....................................................................................... 85
4.3 Material Used for Construction .......................................................................................... 93
4.3.1 Longitudinal Reinforcement .................................................................................... 93
4.3.2 Transverse Reinforcement ....................................................................................... 94
4.3.3 Concrete................................................................................................................... 97
4.3.4 Transverse Conduits................................................................................................. 99
4.4 Construction of Decked Bulb T beams............................................................................. 100
4.4.1 Construction of Reinforcement Cage..................................................................... 100
12. xii
4.4.2 Construction of Modular Deck System.................................................................. 103
4.4.3 Fabrication of Decked Bulb T Shape Formwork................................................... 106
4.4.4 Placement of Reinforcement Cage within Formwork ........................................... 108
4.4.5 Prestressing of CFCC Strands................................................................................ 110
4.4.6 Placement of Concretes.......................................................................................... 114
4.4.7 Curing of Concrete................................................................................................. 118
4.4.8 Deforming, Prestress Transfer and Beam Stacking............................................... 119
4.4.9 Concrete Compressive Strength Test..................................................................... 122
4.5 Instrumentation ................................................................................................................. 125
4.5.1 Strain Gages........................................................................................................... 126
4.5.2 Force Transducers (Load Cells)............................................................................. 126
4.5.3 Linear Motion Transducers.................................................................................... 127
4.5.4 Linear Variable Differential Transducer................................................................ 127
4.5.5 Data Acquisition System........................................................................................ 128
4.6 Instrumentation of Decked Bulb T Beams........................................................................ 130
4.7 Experimental Testing........................................................................................................ 135
4.7.1 Experimental Testing of Decked Bulb T beams in Shear...................................... 139
4.7.2 Experimental Testing of Decked Bulb T beams in Flexure................................... 145
4.7.3 Decompression Load Test of the Beam................................................................. 148
CHAPTER 5 RESULTS AND DISCUSSION........................................................................... 149
5.1 General Outline................................................................................................................. 149
5.2 Behavior of Decked Bulb T Beams Tested in Shear ........................................................ 150
5.2.1 Modes of Failure.................................................................................................... 152
5.2.2 Pattern of Crack Development and Shear Force-Crack Width Response.............. 158
5.2.3 Applied Load-Deflection and Shear Force–Deflection Response......................... 164
13. xiii
5.2.4 Cracking Force and Ultimate Failure Force........................................................... 166
5.2.5 Shear Force-Concrete Compressive Strains Response .......................................... 169
5.2.6 Ductility Ratio........................................................................................................ 173
5.3 Flexural Behavior of Decked Bulb T Beams.................................................................... 179
5.3.1 Beam HB-100-Mid-0SS ........................................................................................ 180
5.3.2 Beam DB-132-Mid-0ES ........................................................................................ 185
CHAPTER 6 COMPARISON OF RESULTS............................................................................ 191
6.1 General Outline................................................................................................................. 191
6.2 Comparison between Experimental Results of Beams Tested in Shear ........................... 192
6.2.1 Effect of a/d Ratio on Shear Force–Deflection Response ..................................... 194
6.2.2 Effect of a/d Ratio on Cracking and Ultimate Shear Resistance ........................... 196
6.2.3 Effect of a/d Ratio on Ductility Ratio.................................................................... 198
6.2.4 Effect of a/d Ratio on the Modes of Shear Failure ................................................ 199
6.3 Comparison between Experimental Results of Beams Tested in Flexure........................ 200
6.3.1 Introduction............................................................................................................ 200
6.3.2 Comparison of applied load-deflection response................................................... 202
6.3.3 Comparison of cracking load, ultimate load and nominal moment capacity......... 203
6.3.4 Ductility Ratio........................................................................................................ 205
6.4 Comparison between Experimental and Analytical Results............................................. 206
6.4.1 Introduction............................................................................................................ 206
6.4.2 Comparison between Experimental and Analytical Results in Shear.................... 206
6.4.3 Comparison between Experimental and Analytical Results in Flexure................. 209
CHAPTER 7 SUMMARY AND CONCLUSIONS................................................................... 211
7.1 Research Summary ........................................................................................................... 211
7.2 Conclusion ........................................................................................................................ 212
14. xiv
CHAPTER 8 RECOMMENDATIONS...................................................................................... 214
8.1 Recommendation for Future Studies ................................................................................ 214
REFERENCES ........................................................................................................................... 216
APPENDIX A: ANALYTICAL CALCULATIONS FOR DECKED BULB T BEAMS ......... 233
A.1 Ductal Beam Design ........................................................................................................ 234
A.1.1 Design of Ductal Beam in Flexure........................................................................ 236
A.1.1.1 Concrete Properties................................................................................ 236
A.1.1.2 Cross Sectional Properties ..................................................................... 237
A.1.1.3 Reinforcement Properties....................................................................... 243
A.1.1.3.1 Longitudinal Reinforcement Properties.................................. 243
A.1.1.3.2 Transverse Reinforcement Properties ..................................... 244
A.1.1.4 Prestress Loss Calculations.................................................................... 244
A.1.1.4.1 Initial Prestressing Force in the Beam .................................... 244
A.1.1.4.2 Prestress Loss Calculation from Experimental Decompression
Load ........................................................................................................ 244
A.1.1.4.3 Prestress Loss Calculation from Experimental Cracking Load
................................................................................................................. 245
A.1.1.4.4 Prestress Loss Calculation as per AASHTO (2010)............... 247
A.1.1.4.5 Effective Prestressing Force in the Beam ............................... 248
A.1.1.5 Stress Check during Prestress Transfer.................................................. 248
A.1.1.5.1 Stress at Mid Span................................................................... 248
A.1.1.5.2 Stress at Support...................................................................... 249
A.1.1.5.3 Stress Limit as per ACI 440.4R-04 (2004) ............................. 249
A.1.1.5.4 Stress Limit as per AASHTO (2010)...................................... 249
A.1.1.5.5 Stress Check as per ACI 440.4R-04 (2004) and AASHTO
(2010)...................................................................................................... 250
15. xv
A.1.1.6 Calculations for Neutral Axis Depth...................................................... 250
A.1.1.7 Calculations for Balanced Neutral Axis Depth...................................... 259
A.1.1.8 Mode of Flexural Failure ....................................................................... 259
A.1.1.9 Calculations for Nominal Flexural Moment.......................................... 260
A.1.1.10 Calculations for Ultimate Flexural Load for the Beam........................ 260
A.1.1.11 Calculations for Cracking Moment and Cracking Load for the Beam 260
A.1.1.12 Calculations for Camber ...................................................................... 261
A.1.2 Design of Ductal Beam in Shear........................................................................... 261
A.1.2.1 Shear Capacity as per JSCE (2006) ....................................................... 262
A.1.2.2 Shear Capacity as per AFGC (2002)...................................................... 262
A.1.2.3 Shear Capacity as per Canadian Code – Almansour and Lounis (2009)263
A.1.2.4 Shear Capacity as per Australian Code – Gowripalan and Gilbert (2010)
............................................................................................................................. 264
A.2 Hybrid Beam Design........................................................................................................ 265
A.2.1 Design of Hybrid Beam in Flexure....................................................................... 266
A.2.1.1 Concrete Properties................................................................................ 266
A.2.1.2 Cross Sectional Properties ..................................................................... 267
A.2.1.3 Reinforcement Properties....................................................................... 273
A.2.1.3.1 Longitudinal Reinforcement Properties.................................. 273
A.2.1.3.2 Transverse Reinforcement Properties ..................................... 274
A.2.1.4 Prestress Loss Calculations.................................................................... 274
A.2.1.4.1 Initial Prestressing Force in the beam..................................... 274
A.2.1.4.2 Prestress Loss Calculation from Experimental Decompression
Load ........................................................................................................ 275
A.2.1.4.3 Prestress Loss Calculation from Experimental Cracking Load
................................................................................................................. 276
16. xvi
A.2.1.4.4 Prestress Loss Calculation as per AASHTO (2010)............... 277
A.2.1.4.5 Effective Prestressing Force in the Beam ............................... 278
A.2.1.5 Stress Check during Prestress Transfer.................................................. 279
A.2.1.5.1 Stress at Mid Span................................................................... 279
A.2.1.5.2 Stress at Support...................................................................... 279
A.2.1.5.3 Stress Limit as per ACI 440.4R-04 (2004) ............................. 279
A.2.1.5.4 Stress Limit as per AASHTO (2010)...................................... 280
A.2.1.5.5 Stress Check as per ACI 440.4R-04 (2004) and AASHTO
(2010)...................................................................................................... 280
A.2.1.6 Calculations for Balanced Reinforcement Ratio.................................... 280
A.2.1.7 Calculations for Balanced Neutral Axis Depth...................................... 282
A.2.1.8 Calculation for the Reinforcement Ratio of the beam ........................... 283
A.2.1.9 Mode of Flexural Failure ....................................................................... 284
A.2.1.10 Calculations for Nominal Flexural Moment........................................ 284
A.2.1.10.1 Calculation for the Depth of Neutral Axis as per Grace and
Singh (2002) Approach........................................................................... 284
A.2.1.10.2 Calculation for the Depth of Neutral Axis as per Traditional
Strain Compatibility Method .................................................................. 286
A.2.1.11 Calculations for Nominal Capacity of the Section............................... 288
A.2.1.12 Calculations for Ultimate Flexural Load for the Beam........................ 289
A.2.1.13 Calculations for Cracking Moment and Cracking Load for the Beam 289
A.2.1.14 Calculations for Camber ...................................................................... 289
A.2.2 Design of Hybrid Beam in Shear.......................................................................... 290
A.2.2.1 Shear Capacity as per JSCE (2006) ....................................................... 291
A.2.2.2 Shear Capacity as per AFGC (2002)...................................................... 291
A.2.2.3 Shear Capacity as per Canadian Code – Almansour and Lounis (2009)292
17. xvii
A.2.2.4 Shear Capacity as per Australian Code – Gowripalan and Gilbert (2010)
............................................................................................................................. 292
18. xviii
LIST OF FIGURES
Figure 1.1.1 Deficient bridges in USA (according to national bridge inventory, FHWA)............. 1
Figure 1.1.2 Corrosion of prestressed strand in box beam bridge (Naito et al. 2006).................... 2
Figure 2.2.1 Optimized model of UHPC in comparison with conventional concrete (Nishikawa
and Morita 2006)........................................................................................................................... 14
Figure 2.2.2 Typical sequence of mixing of UHPC (Graybeal 2006) .......................................... 16
Figure 2.2.3 Formation of joint due to un-proper mixing and flow of UHPC (Alessandro 2013)17
Figure 2.2.4 Two ways of UHPC placement (Courtesy: Kim et al. 2008)................................... 17
Figure 2.2.5 Proper alignment of fibers to restrict cracks in flexural members (D’Alessandro,
2013) ............................................................................................................................................. 17
Figure 2.2.6 Construction of bridge street bridge (Grace et al. 2002).......................................... 25
Figure 2.4.1 Typical shear & bending stress profile (Naaman 2004)........................................... 38
Figure 2.4.2 Principal stresses presented by Mohr’s circle for non-prestressed and prestressed
concrete element along neutral axis (Naaman 2004).................................................................... 39
Figure 2.4.3 Effect of shear span-to-depth (a/d) ratio on shear strength of concrete beam without
shear reinforcement (Laskar et al. 2010) ...................................................................................... 42
Figure 2.4.4 Types of crack formation along the span of the beams (Gilbert & Mickleborough
2005) ............................................................................................................................................. 49
Figure 2.4.5 Shear compressions failure (Rout 2013) .................................................................. 50
Figure 2.4.6 Progression of crack and web crushing failure in concrete beam under shear load setup
(Heckmann, 2008)......................................................................................................................... 50
Figure 2.4.7 Shear diagonal failure (Tadros et al. 2011) .............................................................. 51
Figure 2.4.8 Various types of failure modes observed in test beams (Park and Naaman 1999) (a)
shear-tendon rupture failure; (b) shear-tension failure; (c) shear-compression failure; and (d)
flexural-tension failure.................................................................................................................. 53
Figure 2.4.9 Experimental results of test beams investigated by Rout (2013) ............................. 55
Figure 3.2.1 Equivalent Whitney stress block recommended by ACI/AASHTO ........................ 60
Figure 3.2.2. Strain hardening (a) and strain softening (b) Law of AFGC and Setra (2002) for
UHPC at the serviceability limit state........................................................................................... 62
Figure 3.2.3. Stress-strain relationship for ductal section (a) with reinforcement and (b) without
reinforcement (Gowripalan and Gilbert 2000) ............................................................................. 64
19. xix
Figure 3.2.4. Stress-Strain behavior of UHPC according to (a) Garcia (2007) Model and (b)
Graybeal (2008) Model................................................................................................................. 65
Figure 3.2.5 Trilinear stress – strain behavior of UHPC given by Vande Voort et al. (2008) ..... 67
Figure 3.2.6. Modified AFGC-Setra Stress-Strain Model developed by Steinberg (2010).......... 68
Figure 3.3.1. Flexural Strain and Stress Distribution for Non-Prestressed UHPC Beam (Almansour
and Lounis, 2009) ......................................................................................................................... 70
Figure 3.3.2. Experimental and simplified stress strain behavior of UHPC (Garcia 2007) ......... 73
Figure 3.3.3. Internal Stress Behavior for Prestressed UHPC Section (Garcia 2007).................. 74
Figure 4.3.1. Carbon Fiber Composite Cable (CFCC) Roll ......................................................... 94
Figure 4.3.2. Stirrup type A [Dimension in inch (mm)]............................................................... 95
Figure 4.3.3. Stirrup type B [Dimension in inch (mm)] ............................................................... 95
Figure 4.3.4. Stirrup type C [Dimension in inch (mm)] ............................................................... 96
Figure 4.3.5. Mixing of ingredient and production of UHPC for the construction of beams at Center
for Innovative Material Research (CIMR), LTU.......................................................................... 98
Figure 4.3.6. Fabrication of transverse conduit used in hybrid beams at interior diaphragm ...... 99
Figure 4.4.1. Process of construction of hybrid beam reinforcement cage over wooden zig..... 101
Figure 4.4.2. Completed hybrid beam reinforcement cage......................................................... 102
Figure 4.4.3 Various components of modular deck system........................................................ 104
Figure 4.4.4 Completion of modular deck system construction ................................................. 105
Figure 4.4.5. Fabrication of decked bulb T beam shape formwork from styrofoam.................. 107
Figure 4.4.6 Construction of hybrid beam formwork with reinforcement cage......................... 109
Figure 4.4.7 Construction of ductal beam with reinforcement cage........................................... 110
Figure 4.4.8 Various components of anchorage system to prestress CFCC strands................... 111
Figure 4.4.9 Process involved in pretensioning of prestressing strands of beams...................... 112
Figure 4.4.10 Placement of concrete in hybrid beam ................................................................. 115
Figure 4.4.11 Placement of UHPC in ductal beam..................................................................... 116
Figure 4.4.12 Measurement of workability of HSC (Cone Test) ............................................... 117
Figure 4.4.13. Measurement of workability of UHPC................................................................ 117
Figure 4.4.14 Curing of beam..................................................................................................... 118
Figure 4.4.15 Deforming, prestress transfer and stacking of hybrid beam................................. 119
Figure 4.4.16 Deforming, prestress transfer and stacking of ductal beam ................................. 120
20. xx
Figure 4.4.17 Monitoring of prestressing force in ductal beam.................................................. 121
Figure 4.4.18 Concrete cylinders for compressive strength test................................................. 122
Figure 4.4.19 Increase of average compressive strength of concrete with curing...................... 124
Figure 4.4.20 Increase of average split tensile strength of UHPC with curing .......................... 124
Figure 4.4.21 Failure of concrete cylinders under compression and tension.............................. 125
Figure 4.5.1 Typical linear strain gage (Vishay Instruments, http://www.vishaypg.com/micro-
measurements/stress-analysis-strain-gages/linear-pt250-2) ....................................................... 126
Figure 4.5.2 Load cell used for monitoring forces...................................................................... 127
Figure 4.5.3 Linear Motion Transducer...................................................................................... 127
Figure 4.5.4 Typical rosette arrangement of LVDT on web of the beam................................... 128
Figure 4.5.5 Data acquisition system.......................................................................................... 129
Figure 4.5.6 Typical setup of data acquisition system during experimental investigation......... 130
Figure 4.6.1 Typical external instrumentation on the hybrid beam............................................ 131
Figure 4.6.2 Typical external instrumentation on the ductal beam............................................. 132
Figure 4.6.3 Typical internal instrumentation on the ductal beam ............................................. 132
Figure 4.7.1 Chronological order of experimental test conducted on beams ............................. 137
Figure 4.7.2 Schematic presentation of experimental test conducted on the hybrid beam and ductal
beam............................................................................................................................................ 138
Figure 4.7.3 Typical shear test setup for decked bulb T beams.................................................. 139
Figure 4.7.4 Shear test setup for beam HB-100-3-0SS............................................................... 140
Figure 4.7.5 Shear test setup for beam HB-100-5-0SS............................................................... 141
Figure 4.7.6 Shear test setup for beam HB-100-5-0SS............................................................... 142
Figure 4.7.7 Shear test setup for beam HB-100-6-0SS............................................................... 143
Figure 4.7.8 Shear test setup for beam DB-132-3-0ES .............................................................. 144
Figure 4.7.9 Shear test setup for beam DB-132-4-0ES .............................................................. 145
Figure 4.7.10 Typical flexure test setup for decked bulb T beams............................................. 146
Figure 4.7.11 Typical setup of hybrid beam for flexure test ...................................................... 147
Figure 4.7.12 Typical setup of ductal beam for flexural test...................................................... 147
Figure 4.7.13 Strain gage installed on the soffit of the beam for decompression test................ 148
Figure 5.2.1 Shear diagonal failure observed in beam HB-100-3-0SS....................................... 153
Figure 5.2.2 Shear diagonal failure observed in beam HB-100-4-0SS....................................... 154
21. xxi
Figure 5.2.3 Compression flexural failure observed in beam HB-100-5-0SS............................ 155
Figure 5.2.4 Compression flexural failure observed in beam HB-100-6-0SS............................ 156
Figure 5.2.5 Diagonal shear failure observed in beam DB-132-3-0ES ...................................... 157
Figure 5.2.6 Diagonal shear failure of observed in beam DB-132-4-0ES.................................. 158
Figure 5.2.7 Crack pattern observed in beam HB-100-3-0SS .................................................... 161
Figure 5.2.8 Crack pattern observed in beam HB-100-4-0SS .................................................... 161
Figure 5.2.9 Crack pattern observed in beam DB-132-3-0ES.................................................... 162
Figure 5.2.10 Crack pattern observed in beam DB-132-4-0ES.................................................. 162
Figure 5.2.11 Shear force – crack width of hybrid beams at a/d ratio of 3 and 4....................... 162
Figure 5.2.12 Shear force – crack width of ductal beams at a/d ratio of 3 and 4 ....................... 163
Figure 5.2.13 Comparison of crack width development between UHPC and HSC in hybrid beam
at a/d ratios of 4........................................................................................................................... 163
Figure 5.2.14 Applied load – deflection response of all hybrid beams tested in shear at varying a/d
ratio ............................................................................................................................................. 165
Figure 5.2.15 Shear force – deflection response of hybrid beams failed in shear at a/d ratio of 3
and 4............................................................................................................................................ 165
Figure 5.2.16 Shear force – deflection response for ductal beam in shear at varying a/d ratio.. 166
Figure 5.2.17 Cracking load and ultimate failure load of all hybrid beams tested in shear at varying
a/d ratios...................................................................................................................................... 168
Figure 5.2.18 Cracking shear forces for all hybrid beam and ultimate shear force for the hybrid
failed in shear at varying a/d ratio............................................................................................... 168
Figure 5.2.19 Comparison of cracking and ultimate shear resistance of ductal beams tested in shear
at varying shear span-to-depth ratio............................................................................................ 169
Figure 5.2.20 Comparison between maximum concrete compressive strains observed along the
span at three different locations for hybrid beams tested in shear at varying a/d ratio............... 171
Figure 5.2.21 Shear force – maximum top flange concrete compressive strain response for hybrid
beams tested in shear at varying shear span-to-depth ratio......................................................... 172
Figure 5.2.22 Shear force – top flange concrete compressive strain observed in ductal beam tested
in shear at varying shear span-to-depth ratio .............................................................................. 172
Figure 5.2.23 Shear force–tensile strain response of bottom prestressing strand of ductal beam
tested in shear at varying a/d ratio .............................................................................................. 173
22. xxii
Figure 5.2.24 Ductility ratio for beam HB-100-3-0SS ............................................................... 175
Figure 5.2.25 Ductility ratio for beam HB-100-4-0-SS.............................................................. 175
Figure 5.2.26 Ductility ratio for beam HB-100-5-0SS ............................................................... 176
Figure 5.2.27 Ductility ratio for beam HB-100-6-0SS ............................................................... 176
Figure 5.2.28 Ductility ratio for beam DB-132-3-0ES............................................................... 177
Figure 5.2.29 Ductility ratio for beam DB-132-4-0ES............................................................... 177
Figure 5.2.30 Comparison between ductility ratios experienced by hybrid test beams in shear at
varying shear span-to-depth ratio................................................................................................ 178
Figure 5.2.31 Comparison between ductility ratios experienced by ductal test beams in shear at
varying shear span-to-depth ratio................................................................................................ 178
Figure 5.3.1 Crack pattern observed in beam HB-100-Mid-0SS before ultimate flexural test .. 182
Figure 5.3.2 Applied load – deflection response for beam HB-100-Mid-0SS ........................... 182
Figure 5.3.3 Flexural compression failure of beam HB-100-Mid-0SS ...................................... 183
Figure 5.3.4 Applied load-concrete compressive strain response for beam HB-100-Mid-0SS.. 183
Figure 5.3.5 Applied load-tensile strain response for HB-100-Mid-0SS ................................... 184
Figure 5.3.6 Applied load – Concrete strain at the soffit for beam HB-100-Mid-0SS............... 184
Figure 5.3.7 Applied load – deflection response for beam DB-132-Mid-0ES........................... 187
Figure 5.3.8 Crack pattern observed in beam DB-132-Mid-0ES ............................................... 187
Figure 5.3.9 Flexural tension failure of the beam DB-132-Mid-0ES......................................... 188
Figure 5.3.10 Applied load – Concrete compressive strain response for DB-132-Mid-0ES ..... 189
Figure 5.3.11 Applied load – Tensile strain response for DB-132-Mid-0ES............................. 189
Figure 5.3.12 Ductility ratio for beam DB-132-Mid-0ES .......................................................... 190
Figure 5.3.13 Applied load – Concrete strain at the soffit for beam HB-100-Mid-0SS............. 190
Figure 6.2.1 Comparison of shear force – deflection response of hybrid beams and HSC beams
reinforced with CFCC stirrups as investigated by Rout (2013) under similar a/d ratios............ 195
Figure 6.2.2 Comparison of shear force – deflection response of hybrid beams and HSC beams
reinforced with steel stirrups as investigated by Rout (2013) under similar a/d ratios............... 196
Figure 6.2.3 Comparison of cracking and ultimate shear forces of hybrid, ductal & HSC beams
investigated by Rout (2013) under similar a/d ratios.................................................................. 197
Figure 6.3.1 Comparison between applied load – deflection response of ductal and HSC beams
investigated by Grace et al. (2015) under similar flexure load setup ......................................... 203
23. xxiii
Figure 6.3.2 Comparison between cracking load, ultimate load and nominal moment capacity of
ductal and HSC beams investigated by Grace et al. (2015) under similar flexure load setup.... 204
24. xxiv
LIST OF TABLES
Table 2.2.1 Mix design of various types of UHPC (Russell and Graybeal, 2013)....................... 13
Table 2.2.2 Tensile strength of UHPC according to various test (Graybeal 2006) ...................... 18
Table 2.4.1 Failure modes for FRP reinforced beams based on energy ratio (Grace et al. 1998) 32
Table 3.2.1 Stress – Strain behavior of UHPC by Vande Voort et al. (2008).............................. 66
Table 4.3.1. Material properties of longitudinal reinforcement used in beams............................ 93
Table 4.3.2. Material properties of transverse reinforcement used in beams ............................... 96
Table 4.3.3. Mix design for HSC per cubic yard (Mc Coig Co., MI)........................................... 97
Table 4.3.4. Mix design for UHPC per cubic yard (Lafarge, North America)............................. 97
Table 4.4.1. Material properties of styrofoam used in the construction of beams...................... 106
Table 4.4.2 Elongation measured on prestressing strands .......................................................... 113
Table 4.4.3. Average strength of concrete cylinders .................................................................. 123
Table 4.6.1 Various sensor types & their respective locations in the beam ............................... 133
Table 4.7.1 Nomenclature of test beams..................................................................................... 137
Table 5.2.1 Summary of experimental results of all test beams in shear.................................... 151
Table 5.2.2 Summary of concrete strain experienced by all test beams in shear ....................... 171
Table 5.2.3 Comparison between ductility ratios experienced by all test beams in shear varying
shear span-to-depth (a/d) ratio .................................................................................................... 179
Table 6.2.1 Comparison of experimental results of hybrid beam and HSC decked bulb T beams
investigated by Rout (2013) in shear .......................................................................................... 194
Table 6.2.2 Summary of inelastic energy, elastic energy and ductility ratio experienced by hybrid
beams and HSC beams tested in shear........................................................................................ 199
Table 6.3.1 Comparison between ductal and HSC beams tested in flexure ............................... 202
Table 6.3.2 Summary of inelastic energy, elastic energy and ductility ratios experienced by ductal
and HSC beams tested in flexure................................................................................................ 205
Table 6.4.1 Comparison between experimental and analytical results of hybrid and ductal beams
tested in shear.............................................................................................................................. 209
Table 6.4.2 Comparison between experimental and analytical results for the hybrid and ductal
beams tested in flexure................................................................................................................ 210
25. 1
CHAPTER 1 INTRODUCTION
1.1 Statement of the Problem
One out of nine bridges in the United States is rated structurally deficient (ASCE 2013) and needs
major improvement ranging from deck replacement to complete reconstruction. According to a
recent 2013 America’s infrastructure report cards conducted by the American Society of Civil
Engineers, the United States consists of 607,380 bridges, out of which 66,749 bridges are
structurally deficient and 84,748 bridges are functionally obsolete (ASCE 2013). Figure 1.1.1
shows the statistics of structurally deficient and functionally obsolete bridges till 2012. Thus, based
on the present state of condition and performance, the United States bridges hold a Grade Point
Average (GPA) score of C+
from the scale of A to F and need $20.5 billion each year to eliminate
backlog of bridge deficiency by the year 2028 as estimated by the Federal Highway Administration
(FHWA). Therefore, in future applications, design engineers seeks a new and better way to build
bridges which require less maintenance and budget over a longer period.
Figure 1.1.1 Deficient bridges in USA (according to national bridge inventory, FHWA)
0
100
200
300
400
500
600
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
0
100
200
300
400
500
600
NumberofBridges(inthousands)
Year
NumberofBridges(inthousands)
# Total Bridges # Structural Deficient # Funtional Obsolete # Total Deficient Bridges
26. 2
Since 1950, steel prestressed side-by-side box-beam bridges have been a popular choice of precast
prestressed bridges. This type of bridges was preferred due to its typical cross-sectional properties
of smaller beam depth-to-span ratio. According to Precast Concrete Institute (PCI), the primary
reasons for the gradual deterioration of the service lifespan of the bridges are mainly due to a)
increase in the vehicle sizes, weights and traffic volumes; b) faster degradation of conventional
concrete due to their low strength and durability, and c) the most important factor is the corrosion
of steel reinforcement due to severe environmental conditions. Figure 1.1.2 shows corrosion of
prestressed steel stands in the box beam bridge system (Naito et al. 2006).
Figure 1.1.2 Corrosion of prestressed strand in box beam bridge (Naito et al. 2006)
In today’s 21st
century of groundbreaking advancement in the field of research and development,
various engineers have found several alternative bridge beam cross-sections followed by different
methodologies for the construction and numerous types of innovative materials to address the
aforementioned problems associated with the bridge construction industry. The significant
breakthrough in the concrete technology so far with the greatest power to transform product design
and service life of the precast concrete industry in the U.S. is Ultra High Performance Concrete
(UHPC) as a concrete and Fiber Reinforced Polymer (FRP) as a reinforcement. Both of these
materials are relatively new in the field of construction. Their superior performance in terms of
strength, durability, long-term stability exhibited a greater ability to produce groundbreaking and
innovative structure which is still under research. In addition, FRP possesses immense potentials
27. 3
and advantages over steel as a reinforcement, owing to their distinguishable properties such as
non-corrosive nature, low relaxation, superior in fatigue, lighter in weight and higher ultimate
tensile strength or higher strength to weight ratio. But due to FRP linear stress-strain material
characteristics, all structural element either longitudinally (reinforced/prestressed strands) or
transversely (stirrups) or both reinforced with FRP are prone to catastrophic brittle failure with a
sign of abrupt rupture of either strands or stirrups or both without showing any yielding, unlike
steel. Therefore, all FRP reinforced/prestressed structural elements are encouraged for over-
reinforced design section (ACI 440.1R-06 2006) to prefer a more comparatively ductile failure
through concrete compression flexural failure. Similarly, in order to prevent sudden collapse of
the concrete structure by shear due to lack of proper and adequate placement of stirrups (either
steel or FRP) (Mitchell et al. 2011), beam sections were mostly over-reinforced with stirrups to
resist maximum anticipated shear stresses. This possibly changes the catastrophic shear failure into
a more favorable flexural failure with sufficient warning of failure in terms of large noticeable
deflection and cracking prior to collapse.
1.2 Hybrid and Ductal Precast Prestressed Decked Bulb T-Beams
The present research investigation introduces two state-of-the-art long lasting corrosion free
innovative precast prestressed decked bulb T beams prestressed with Carbon Fiber Composite
Cables (CFCC) as a replacement to traditional HSC box beams or T beams exhibiting potential
sudden shear and flexural failure. The two types of CFCC prestressed decked bulb T beam
proposed through the present research investigation are: hybrid beam, and ductal beam. These
beams are efficiently constructed with Ultra High Performance Concrete (UHPC) without using
stirrups either at critical shear span or throughout the entire span of the beam. The hybrid and
ductal beam adopt the state-of-the-art decked bulb T beam design as proposed by Grace et al.
(2012) for precast prestressed beams. Bridges made of side-by-side box beam lack space for
inspections to the critical elements which leads to the unexpected failure of the bridge. Thus, Grace
et al. (2012) proposed decked bulb T-beam bridge system which are inbuilt with deck and provides
space underneath the bridge system for inspection. The hybrid beam is constructed by placing
UHPC without stirrups in the critical shear span of the beam at both ends. The middle flexural
span of the beam was constructed with High Strength Concrete (HSC) with stirrups. The hybrid
beam address the use of UHPC without shear stirrups in the critical shear span of CFCC
28. 4
reinforced/prestressed decked bulb T beams to mitigate potential sudden shear failure of the
bridges. Whereas, the ductal beam mitigates potential sudden flexural failure of under-reinforced
CFCC prestressed decked bulb T beams without using any shear reinforcement throughout the
span. In addition, ductal beam efficiently reduces the beam cross-sectional area and designed as
under-reinforced beam in order to reduce the consumption of expensive UHPC and CFCC
material. Further, the ductal and hybrid beams were easy to build, long lasting and require less
maintenance.
In total, hybrid and ductal beams proposes following eight advantages as listed below:
Advantage 1: Mitigates either the shear or flexural sudden failure of FRP reinforced/prestressed
bridge system by enhancing their shear capacity, inelastic energy absorption and deflection with
profound cracking or warning of failures before collapse.
Advantage 2: Efficient utilization of the expensive UHPC and CFCC materials. The consumption
of UHPC is reduced either by reducing the cross-sectional area of the beam or by employing only
within the highly stressed regions such as critical shear span along the beam length. The amount
of reinforcement is reduced by reducing the cross-sectional area of the beam. Thus, building an
efficient, stronger and lighter bridge girders.
Advantage 3: Eliminates shear stirrups either partially in the critical shear span or completely
throughout the entire span. This makes the construction of reinforcement cage easier and faster.
This also helps in solving the workability issues such as the development of concrete voids or
honeycombs due to the congestion of the reinforcement cage.
Advantage 4: Increase in the span-to-depth ratio of the beam. The use of UHPC which possesses
superior characteristic compressive and tensile strength in comparison with HSC in the critical
shear span of the beam increases the ability of the beam to sustain higher bursting forces generated
due to higher prestressing force in the beam leading to lighter and longer beams.
Advantage 5: Replaces the traditional corrosive steel reinforcement with Carbon Fiber Composite
Cables (CFCC) which are non-corrosive, low relaxation, lighter in weight and higher in ultimate
tensile strength properties.
29. 5
Advantage 6: Generates the valuable experimental research data for the UHPC beam section
reinforced/prestressed with FRP for the development of a unified design guidelines and codes.
Advantage 7: Provides a sufficient gap on both sides and bottom of the hybrid or ductal beam
bridge system for the passage of utilities and helps in visual inspection and maintenance of any
progressive damage caused due to corrosion.
Advantage 8: Provides an inbuilt deck on bridge girders which eliminates the on-site preparation
and construction time. Thus, it accelerates on-site construction of bridge and involves less
disruption in the normal flow of traffic.
1.3 Motivation
Even after decades of experimental research and latest use of highly sophisticated computational
tools, the shear transfer mechanism has always been a complex phenomenon to understand in depth
due to the involvement of large number of variables. The shear behavior of structural members has
always been a point of discussion among researchers, and even it becomes worse when several
issues associated with the use of stirrups are involved in the studies such as: (a) shear capacity of
a section increases with decreasing the spacing between the stirrups. However, various code limit
the minimum spacing or maximum use of stirrups to avoid the congestion of reinforcement cage,
b) Vulnerability of steel stirrups towards corrosion, c) Reduction in tensile strength of CFCC
stirrups due to bend effect (Rout 2013), d) limitation on the maximum spacing of stirrups to avoid
wider shear cracks especially in prestressed concrete section. The use of steel fibers in
reinforced/prestressed concrete members is a viable alternative solution for increasing the shear
capacity of the section without using stirrups. According to Imam et al. (1997), the shear capacity
of concrete section increases comparatively at a higher rate with increasing the amount of steel
fiber than increasing in their nominal flexural capacity (Mn). Depending upon the percentage of
use of steel fibers, steel fibers are capable of increasing the shear capacity up to their nominal
flexural capacity (Mu = 100% Mn) (Russo et al. 1991) which ultimately leads to more of a ductile
shear/flexural failure. Thus, the mode of sudden brittle shear failure in a beam can be mitigated
into a ductile flexural failure by utilizing steel fibers in a normal strength concrete section.
According to Park and Naaman (1999), prestressed concrete beams with fiber reinforced polymer
(FRP) tendons are susceptible to shear-tendon rupture failure. The shear-tendon rupture failure is
30. 6
a unique mode of failure caused due to rupture of tendon initiated by dowel shear action acting on
the shear-cracking plane. This phenomenon is observed due to the FRPs linear stress-strain
characteristics and low shear resistance in transverse direction. Park and Naaman (1999) also
recommended that addition of steel fibers in the concrete section can possibly reduce the unique
shear-tendon rupture failure of FRP reinforced/prestressed concrete beams by enhancing their
section shear capacity. Padmarajaiah and Ramaswamy (2001) conducted a rigorous experimental
and analytical work on 13 fully/partially prestressed high-strength concrete beams to study the
influence of fiber content, location of fiber, and the presence/absence of stirrups within the shear
span on the shear behavior of the beam. It was reported that the beams having fibers located only
within the shear span and over the entire cross-section exhibited a similar load-deformation
response and ultimate load to that of beams which had fibers over the entire span. The presence of
fibers within the shear span altered the brittle shear failure to more of a ductile flexure failure.
Thus, it was recommended that the stirrups can be replaced with an equivalent amount of fibers in
the shear span without compromising the overall structural performance of the member. Therefore,
in order to overcome the corrosion problems of steel and the issues on the use of stirrups, it is a
peak time to propose a structure with an innovative design which utilizes the newly developed
construction material i.e. UHPC and CFCC in a more efficient and economical way in solving this
present issues in bridge construction. In addition to the above point, Taylor et al. (2011) conducted
a life cycle cost analysis for bridge girders and recommended that UHPC are expected to provide
at least twice the service life and low cost of maintenance as expected from the conventional
strength concrete compensating the higher initial investment in long term. Similarly, Grace et al.
(2012) demonstrated through the life cycle cost analysis that CFRP bridges are more cost effective
and maintenance free than the traditional steel bridges.
1.4 Research Significance
The present research investigation presents a new technique to construct bridge girders by adopting
the state-of-art decked bulb T-beam design proposed by Grace et al. (2012) for precast prestressed
concrete beams. Newly developed materials i.e. UHPC as concrete and CFCC as reinforcement,
is used in the present research investigation in the construction of bridge girder. The present
research investigation brings an idea of efficient and economical use of costly material through
section hybridization and optimization. Through this novel concept, in addition to the earlier
31. 7
advantages of decked bulb T-beams such as inbuilt deck and open spaces between beams for
inspection and utilities, these proposed decked bulb T-beams make an attempt to mitigate potential
sudden shear and flexural failures of FRP prestressed beams individually by utilizing UHPC and
CFCC efficiently and economically. In order to satisfy the motive of the research investigation,
two kinds of beams are proposed and named as the hybrid and the ductal beams. The hybrid beam
brings the concept of hybrid formulation between two different types of concrete i.e. UHPC and
HSC at different zone/span along the length of the beam to mitigate catastrophic shear failure by
increasing inelastic energy absorption and shear capacity of the beam. On the other hand, ductal
beam brings the concept of section optimization of full UHPC beam section and suggests an
alternative approach to mitigate potential sudden flexural failure for under-reinforced FRP
reinforced/prestressed beam section. Due to the enhanced tensile capacity and the involvement of
steel fibers in the UHPC, it is anticipated that the under-reinforced UHPC beam with FRP
reinforcement will tend to increase the energy absorption or ductility ratio of the beam and will
exhibit more of a ductile flexural failure with ample signals or warning of aloud fiber pullouts
along with excessive cracks and deflection before collapse. The objective behind the study of
ductal beam is to decrease the consumption of UHPC and CFCC reinforcement by reducing the
cross-sectional area in comparison with hybrid beam and cut down the cost of construction by
saving costlier materials and labor manpower. In addition, partial or complete elimination of shear
stirrups in the hybrid and ductal beams also helps in easier and faster construction of reinforcement
cage. The partial or complete elimination of stirrups also relieves concrete workability issues such
as the development of voids or honeycombs which are caused due to improper placement of
concrete in the congested reinforcement cage.
At present, there is no extensive research conducted in the past to mitigate sudden shear and
flexural failure of FRP reinforced/prestressed concrete. In addition, there are no domestic and
international unified design guidelines and codes for the construction of bridge beams with UHPC
and FRPs. Therefore, the experimental data generated through the present research investigation
on these proposed beams will help in developing unified design guidelines and codes for the UHPC
beam section reinforced/prestressed with FRP. Finally, the observed experimental results were
compared with various applicable available design guidelines and codes to determine their level
of conservatism. Therefore, it is of utmost importance and necessary to conduct a complete
32. 8
research investigation on the structural behavior of CFCC decked bulb T-beam constructed with
UHPC and prestressed with CFCC for the Accelerated Bridge Construction (ABC) industry.
1.5 Research Objectives
The primary objective of this research investigation is to mitigate the potential sudden flexural and
shear failure of FRP reinforced/prestressed decked bulb T-beams by employing UHPC and CFCC.
In order to accomplish the objective of the study, the following study was carried out as outlined
below:
A) To study the effect of change in the shear span-to-depth ratio on the shear behavior,
cracking shear resistance, ultimate shear capacity and their modes of failure on the hybrid
and ductal beam.
B) To examine the effect of eliminating shear stirrups either partially or completely in a CFCC
prestressed decked bulb T-beams.
C) To evaluate the flexural behavior, cracking and the ultimate flexural capacity of hybrid and
ductal beams.
D) To compare the experimental results of the hybrid and ductal beams with the experimental
results of a similarly reinforced HSC beams investigated by Rout (2013) & Grace et al.
(2015).
E) To compare the various applicable design guidelines and code for predicting the shear and
flexural capacities of UHPC beams prestressed with CFCC.
1.6 Scope of Work
The scope of present research study consisted of conducting experimental investigation and
analytical analysis on decked bulb T-beams constructed with UHPC and reinforced/prestressed
with CFCC. The experimental investigation included construction of two hybrid beams and one
ductal beam. All three beams were 41 ft. (12.25 m) long, with effective span of 40 ft. (12.19 m).
Both the hybrid and ductal beams were subjected to different shear and flexural load configuration.
Further, to provide a better comparative assessment on the performance of the beams under shear
and flexural load, the experimental results of the hybrid and ductal beams were compared with the
experimental results of a similarly reinforced HSC beams investigated by Rout (2013) and Grace
et al. (2015) under similar load configurations. An analytical calculation was developed which
33. 9
determines the flexural capacity of the ductal beam. Finally, a comparative study was carried out
between the results obtained through the experimental investigation and the analytical methods
using applicable design guidelines and codes for UHPC.
1.7 Thesis Outline
The detailed outline of the thesis is described as follows:
Chapter 2: This chapter presents the available literature on the material characteristic of UHPC
and FRP/CFCC and the flexural/shear behavior of reinforced and prestressed concrete
members built from these material.
Chapter 3: This chapter deals with the available design guidelines for the flexural/shear design of
prestressed/reinforced concrete members with FRP and UHPC.
Chapter 4: A detailed experimental investigation is presented in this chapter, including detail
description of the materials used, construction, instrumentation, test setup, and the test
procedure of the hybrid and ductal decked bulb T-beams.
Chapter 5: This chapter presents the detailed discussion of the experimental results for each
individual test conducted on hybrid and ductal beams.
Chapter 6: This chapter compares the experimental test results of the hybrid and the ductal beams
tested in shear and flexure with HSC decked bulb T-beams investigated Rout (2013)
and Grace et al. (2015) tested under similar load configurations. And finally, the
experimental results of both hybrid and ductal beams were compared with predicted
results obtained from available design guidelines and codes.
Chapter 7: This chapter presents the summary and conclusions based on the research investigation.
Chapter 8: This chapter presents recommendations for future studies.
Appendix A: Detailed flexural/shear design calculations according to the applicable design
guidelines and code are presented in this appendix.
34. 10
CHAPTER 2 LITERATURE REVIEW
2.1 Introduction
The prestressed concrete industry has witnessed different types of alternative concrete and
reinforcement for decades. One of the greatest technological and research breakthrough in the field
of construction is the evolution of Ultra High Performance Concrete (UHPC) as the strongest fiber
reinforced concrete with minimum compressive strength of 21 ksi (144.8 MPa) and Fiber
Reinforced Polymer (FRP) as the non-corrodible reinforcement. Both of these emerging materials
possess huge potentials in terms of strength, durability and long term stability. Their ability to
produce revolutionary innovative structures are still under research. Presently, both materials have
limited market application, primarily due to the unavailability of unified design guidelines and
limited research data. Because of the above mentioned issues, the cost of both innovative materials
is extremely high as compared to other available construction materials and carries a very less
limited market application. Hence, the best possible way to increase their market application is by
developing a unique, innovative, and an optimized structure by exploiting the use of these costlier
materials according to their needs and locations. At the same time, these innovative structures
should also provide a very similar or superior behavior than the structures built with the traditional
materials before. Thus, it is of utmost importance to propose an optimized design of the structure
which aims at significantly reducing the cost of construction without compromising the structural
behavior.
Therefore, the present research investigation focuses on prestressed concrete bridge girders by
introducing the concept of hybridization and optimization of expensive concrete and reinforcement
i.e. UHPC and CFCC, respectively. These bridge girders should mitigate catastrophic shear and
flexural failure of CFCC prestressed High Strength Concrete (HSC) bridge girders by increasing
section capacity and inelastic energy absorption. Further, the structural behavior of these beams
are studied under various loading scenarios; shear and flexural load respectively. The present
chapter reviews literature in four broad categories such as available innovative material for
prestressed concrete beams construction, application of available innovative material, bond
strength of UHPC, and the structural behavior of FRP prestressed concrete beams. The subsequent
sections therefore reviews all the available literature currently accessible through various technical
journals published by the American Society of Civil Engineers (ASCE), the American Concrete
35. 11
Institute (ACI), the Transportation Research Board (TRB), the Precast Prestressed Concrete (PCI),
and proceedings of national and international conferences. Section 2.2 discusses various types and
grades of concrete and reinforcements available till date in the market for the construction of
precast prestressed concrete bridges. Section 2.3 discusses various applications of the available
innovative materials towards the development of Accelerated Bridge Construction (ABC)
industry. Section 2.4 discusses the bond strength of UHPC. Lastly, section 2.6 discusses the
structural behavior of prestressed concrete beams constructed from various types and grades of
concrete and reinforcement, and the factors which affects their behavior.
2.2 Available Innovative Materials for Prestressed Bridge Girders
Prestressed concrete is mainly composed of concrete and prestressed reinforcement with or
without non-prestressed reinforcement. In today’s 21st
century of groundbreaking advancement in
the field of research and development, engineers have found several types of innovative concrete
and reinforcement to address the various challenges associated with the bridge construction
industry as mentioned earlier. The most significant concrete technological breakthrough yet with
the greatest power to transform design and service life of the precast prestressed concrete industry
is the development of UHPC as concrete and FRP as reinforcement. Both of these are newly
developed emerging materials in the field of construction. Their superior performance in terms of
strength, durability, long term stability showed an ability to produce groundbreaking, innovative
structure which is still undefined and undiscovered by researchers. Following section in this
chapter will discuss in detail various types and material characteristics of concrete and
reinforcement as a construction material for precast prestressed concrete bridges currently
available in the market.
2.2.1 Concretes
Due to technological breakthrough and research advancement, there has been a consistent
development in the concrete technology. Concrete can be classified as Normal Strength Concrete
(NSC), High Strength Concrete (HSC), Ultra High Performance Concrete (UHPC), etc. ACI 363R-
92 defines HSC as concrete which are made using conventional material, admixture, and
techniques, having specified compressive strength for design of at least 6,000 psi (40 MPa).
Subsequent sub-sections discusses Ultra High Performance Concrete (UHPC) which is important
in the present research investigation.
36. 12
2.2.1.1 Ultra High Performance Concrete (UHPC)
Ultra High Performance Concrete (UHPC) is defined as a concrete having characteristic strength
in excess of 20 ksi (150 MPa) using steel fibers that result in a ductile behavior. Due to a very low
water-cement ratio of less than 0.25 (Nematollahi et al. 2012), major portion of portland cement
particles in UHPC remain un-hydrated and unreacted, making it to behave as fine aggregates with
a particle size ranging from 150 μm to 600 μm. AFGC-SETRA (2002) defines UHPC as “concrete
matrix having compressive strength above 21.7 ksi (150MPa) and internally reinforced with fiber
to ensure non-brittle behavior, with very low water to cementitious material ratio and with minimal
or no coarse aggregates”. Graybeal (2006) defines UHPC class materials as “cementitious-based
composite materials with discontinuous fiber reinforcement, compressive strengths above 21.7 ksi
(150 MPa), pre- and post-cracking tensile strengths above 0.72 ksi (5 MPa), and enhanced
durability via their discontinuous pore structure”. While according to the United States ongoing
ACI 239 design guidelines (2011), UHPC is definition as “concrete that has a minimum specified
compressive strength of 22 ksi (150 MPa) with specified durability, tensile strength, ductility and
toughness requirements; fibers are generally included to achieve specified requirements”. This
section is further subdivided into a multiple number of sub-sections which define characteristic
properties of UHPC.
2.2.1.1.1 Types of UHPC and mix design
Ultra High Performance Concrete (UHPC) is the concrete of new generation which is also known
as Rapid Powder Concrete (RPC) (Nematollahi et al. 2012). In Early 1990s, two separate groups
from France discovered UHPCs. Eiffage group in corporation with Sika created BSI while
Boygues in partnership with Lafarge produced Ductal. Both of these materials have the same
material properties. They both exhibit similar behavior with the only difference in their name. In
1986, Aarup reported a special fiber reinforced high performance concrete called CRC and was
developed by Aalborg Portland. A new class of UHPC material called Cor-Tuf was reported by
the U.S. Army Corps of Engineer at Engineer Research and Development Center. The present
research investigation uses Ductal as the main type of UHPC since Lafarge is the major distributor
in the North America. Depending upon the types of suppliers, various types of concrete mix design
for UHPC exist. Russell and Graybeal (2013) carried out a detailed study to analyze various types
of UHPC and their mix design currently available in the market as presented by the Table 2.2.1.
37. 13
Table 2.2.1 Mix design of various types of UHPC (Russell and Graybeal, 2013)
Supplier
Material
Ductal
(by Lafarge)
CRC
(by Aalborg
Portland)
UHPC
(by Teichmann et al. 2002)
Cor-Tuf
(by US army corps
of engineers)
CEMTEC
(by Rossi)
Mix 1 Mix 2
lb/yd3
(kg/m3
)
(% by Weight)
% by Weight lb/yd3
(kg/m3
) lb/yd3
(kg/m3
) % by Weight lb/yd3
(kg/m3
)
Portland Cement 1200 (712) (28.5) 1.0 1235 (733) 978 (580) 1.0 1770 (1050)
Fine Sand 1720 (1020) (40.8) 0.92 1699 (1008) 597 (354) 0.967 866 (514)
Silica Flour - - - - 0.277 -
Silica Fumes (390) (231) (9.3) 0.25 388 (230) 298 (177) 0.389 451 (268)
Ground Quartz* (355) (211) (8.4) 0.25
308 (183) 503 (131)
- -
0 (0) 848 (325)
HRWRA** (51.8) (30.7) (1.2) 0.0108 55.5 (32.9) 56.2 (33.4) 0.0171 74 (44)
Basalt - - 0 (0) 1198 (711) - -
Accelerator (50.5) (30.0) (1.2) - - - - -
Steel Fibers (263) (156) (6.2) 0.22 to 0.31 327 (194) 324 (192) 0.31 1446 (858)
Water (184) (109) (4.4) 0.18 to 0.20 271 (161) 238 (141) 0.208 303 (180)
Water-Binder Ratio - - 0.19 (0.19) 0.21 (0.21) - -
* Teichmann et al. 2002 considered two design mix and subdivided ground quartz into two groups, ** HRWRA = High Range Water
Reducing Admixture
38. 14
2.2.1.1.2 Composition of UHPC
The characteristics strength of concrete is highly affected by their mix design and mixing of their
constituent such as cements, aggregates and additives. UHPC shows exceptional durability and
strength due to its optimized selection, proportioning and mixing of constituent materials. UHPC
constituent are optimized to produce the minimum void ratio. The largest granular material is fine
sand having size ranging from 15 µm to 600 µm. The main characteristic component of UHPC are
silica fume and quartz flour which have the smallest particle size of 1 µm and 10 µm, respectively.
Silica fumes and quartz flour are mainly responsible for enhancing UHPC mechanical and
durability properties when compared to other types of concrete by filling small interstitial spaces
or voids as showed in the Figure 2.2.1. Silica fume is a pozzolanic material which produces
additional binder material called calcium silica hydrate upon reacting with calcium hydroxide.
Calcium silica hydrate increases cohesion properties of fresh concrete as well as decreases
segregation and bleeding of fresh concrete (Nishikawa and Morita 2006). UHPC consists of finely
graded homogenous concrete matrix composed of fine sand having largest particle size range
between 150 µm and 600 µm, cement particle with average diameter of 15 µm, crushed quartz
with an average diameter of 10 µm and silica fume having the smallest size of 1 µm which fill up
the voids/interstitial spaces. 0.5 in long dispersed steel fibers present in UHPC acts as 3
dimensional reinforcements and helps in enhancing ductile properties of concrete by increasing
residual tensile strength.
Figure 2.2.1 Optimized model of UHPC in comparison with conventional concrete (Nishikawa
and Morita 2006)
Conventional Concrete UHPC
39. 15
2.2.1.1.3 Fiber Reinforcement
Four different kinds of fiber reinforcement are widely used in UHPC and they are straight steel
fibers, deformed steel fibers, high modulus polyvinyl alcohol (PVA) and polypropylene. Ju et al.
(2009) conducted an experimental pullout test to study the effect of variation of steel fibers by
volume on its bond strength with concrete matrix. Based on polynomial regression test, it was
concluded that a maximum bond performance was achieved at 15% of fiber volume. But usually,
2% by volume of steel fibers are usually added to the matrix (Richard and Cheyrezy 1995). Typical
steel fibers have a diameter of 0.008 in. and a length of 0.5 in., covered with brass coating (Richard
and Cheyrezy 1995; Lafarge 2013). Due to the addition of fibers to concrete, it has been proved
that ductility of the concrete members increases (Rossi 2001). The ability of fibers to bridge
individual cracks enhances structural element ductility. Unlike conventional concrete, the stress
required to widen cracks depends upon tensile strength of fibers bridging cracks, concrete tensile
stress and the stress required for fibers to pullout (Mindess et al. 2003; Shaheen and Shrive 2007).
Also according to Richard et al. (1995), addition of fibers leads to increase in compressive strength
as compared to unreinforced UHPC material by stabilizing compressive stresses by means of
internal confinement. Al-Azzawi (2011) confirmed that an increase of 1% fiber volume, leads to
an increase of compressive strength by 5%.
2.2.1.1.4 Mixing of UHPC
Mixing of UHPC is more complicated than that of conventional concrete because UHPC
constituents have to be added in a specific order within time interval. Figure 2.2.2 illustrates the
sequence for the addition of various types of constituents of UHPC with their limiting time frame
of mixing. The procedure of mixing UHPC covered in the present research investigation was
adopted from Graybeal (2006). All components of UHPC are weighted in advance and half of the
High Range Water Reducer (HRWR) or superplasticizer with water is added to premix within 2
minutes. After 1 min, remaining 50% of the superplasticizer is added to mix within 30 second.
After 1 minute, accelerator is added to the mix within a time frame of 1 minute. UHPC is mixed
continuously until the mix turned into a thick paste and once thick paste is achieved. Steel fibers
are added to the mix within a minute and mixing continued until fibers well spread in the mix.
Fibers are usually added at the time when the entire mix seems to be workable.
40. 16
Figure 2.2.2 Typical sequence of mixing of UHPC (Graybeal 2006)
2.2.1.1.5 Placement of UHPC
Kim et al. (2008) conducted several studies using the photographic techniques and the four point
bending test for evaluating the effect of placement of UHPC and the direction of flow on fiber
orientation, dispersion and on its tensile behavior. Their studies showed that the way of placement
of UHPC and direction of flow produces a significant difference of about 50% in developing
UHPC maximum tensile strength. Favorable properties are only obtained when the flow of UHPC
is oriented parallel to the direction of the principal tensile stresses. Further, UHPC does not
consolidate considerably when it flows horizontally by itself during its placement (JSCE 2004;
Nachuk 2008), disturbing the continuity of fiber alignment along the direction of flow at the
intersection as showed in Figure 2.2.3. Nachuk (2008) conducted an experimental investigation on
the effect of vertical placement of UHPC on their strength and concluded that there was no
noticeable decrease on their strength. But, according to AFGC and Setra (2002) UHPC should not
be dropped from a height greater than 1.65 ft. (0.5 m) in order to prevent segregation of fibers from
the matrix. Also in order to protect any formation of skinny thin dry layer on the surface, UHPC
should be poured continuously without any interruption. In exceptional cases, water misting and
All components of
UHPC are weighted
Ductal Premix
added to mixer and
mixed for 2 min
50% of
Superplasticizer
with water added to
premix within 2 min
Remaining 50% of
Superplasticizer with
water added to premix
within 30 Sec
Accelerator are
addded to mix
within 1 min
Steel fibers are
added to mix within
1 min
UHPC
41. 17
agitation through external vibration were recommended when a fresh batch of UHPC was poured
over an older layer of UHPC. Different types of orientation of steel fibers in UHPC result in wide
variation in their strength. Depending upon the orientation of steel fiber, there are two possible
ways of UHPC placement. The first way of placing UHPC is to flow from one end of a form to
the other end (Graybeal 2009) as showed in Figure 2.2.4 (a). This is the most preferred way of
placing UHPC for flexural member because fiber align along the flow path making it more efficient
in bridging flexural cracks. Also, aligns the steel fibers along the principal axis for tensile stresses
at the bottom of the section as showed in Figure 2.2.5. While Figure 2.2.4 (b) shows the second
way of placing UHPC where UHPC is placed transversely to the longitudinal direction of
specimen.
Figure 2.2.3 Formation of joint due to un-proper mixing and flow of UHPC (Alessandro 2013)
Figure 2.2.4 Two ways of UHPC placement (Courtesy: Kim et al. 2008)
Figure 2.2.5 Proper alignment of fibers to restrict cracks in flexural members (D’Alessandro,
2013)
(A
)
(B
)
Placement of UHPC from one end
to the other end of the form
Placement of UHPC transversely to
longitudinal direction of member
42. 18
2.2.1.1.6 Curing of UHPC
After the completion of UHPC placement, curing of UHPC is carried out by covering with a plastic
sheet to prevent loss of moisture through evaporation. Generally, UHPC takes longer initial time
to set as compared to conventional concrete and therefore formwork are removed after certain
specific time depending upon the desired gain of concrete strength. Properties of UHPC are highly
influenced by their method of curing. In order to obtain a higher strength, UHPC is cured with
steamed under controlled temperature and humidity. Ductal is treated under 95% of relative
humidity with a controlled temperature of 194ºF continuously for 48 hours (Graybeal 2006) which
includes 2 hours of increasing temperature and steam, 44 hours of constant temperature and
relative humidity and last two hours of decreasing temperature and steam.
2.2.1.1.7 Material Properties of UHPC
UHPC possesses a superior compressive strength which ranges between 20 to 80 ksi (Graybeal
2006; Lafarge 2013; Richard and Cheyrezy 1995). Graybeal (2006) conducted an experimental
test to study the effect of concrete specimen dimensions on the compressive strength of UHPC. It
was observed that the compressive strength of 2 in. cubic sample of UHPC gives higher
compressive strength than 2in. diameter 4 in. long UHPC cylinder. Tensile strength of UHPC is
usually above 1.45 ksi (Chanvillard and Rigaud 2003), which is considerably higher than those of
conventional concrete. Graybeal (2006) conducted an experimental test to obtain the tensile
strength of UHPC specimen through split tensile strength of cylinders, flexural testing of prism,
direct tension test of notched and un-notched cylinders, and uniaxial tension of briquettes. Table
2.2.2 shows results concluded by Graybeal (2006).
Table 2.2.2 Tensile strength of UHPC according to various test (Graybeal 2006)
Method of Test Tensile Strength (ksi)
First crack split tension test on cylinders 1.58
Ultimate split tension test on cylinders 3.51
First crack flexural test on prism 1.43
Direct tension test on notched cylinders 1.6
Direct tension test on un-notched cylinders 1.43
Uniaxial tension of briquettes 1.22
43. 19
Since modulus of elasticity of any concrete depends upon its compressive strength, UHPC shows
a higher modulus of elasticity as compared to conventional concrete. ACI 318-11 gives the
following equation to calculate elastic modulus (EC) of normal concrete having compressive
strength Cf ′ (psi):
)(57000 psifE CC
′= Equation 2.2.1
The above equation is only applicable for concrete having compressive strength less than 6000 psi
and hence it’s not applicable UHPC. Since the equation given by ACI 318-11 was not appropriate
for concrete above 6000 psi compressive strength, American code ACI 363R-92 proposed another
equation to evaluate modulus of elasticity of concrete having compressive strength in the range of
3000 psi to 12000 psi as given below:
1000000)(40000 +′= psifE CC Equation 2.2.2
For predicting modulus of elasticity of high strength concrete, Ma et al. (2004) also proposed an
equation as given below:
3 )(525000 psifE CC
′= Equation 2.2.3
Both of the above equation 2.2.2 and 2.2.3 predicts modulus of elasticity of UHPC with an
accuracy level of 95.7% and 88.1% to that of the experimental test data of ductal conducted by
Graybeal (2007). UHPC in comparison with HSC possesses a very high compressive and tensile
strength with superior durability. This property of UHPC is attributed due to its very low water-
to-cement ratio and its densely packed characteristic mix design without coarse aggregates. The
presence of randomly distributed steel fibers between 2 to 12% (by volume) serves as 3
dimensional reinforcements at micro-level and also helps to increase its mechanical characteristics
(Almansour and Lounis, 2009).
2.2.1.1.8 Corrosion of steel fibers in UHPC
Oxidation of steel fibers located on the outer surface of the concrete may show some rust stain but
are not structurally considerable. Experimental investigation conducted by Voo (2006) showed
that the corrosion of steel fibers in an aggressive environment did not allowed rusting of steel fibers
44. 20
beyond a depth of 2 mm from the outer surface of the concrete, because UHPC matrix is at least
20 times more impermeable than conventional concrete which restricts the deeper infiltration of
oxygen, moisture and chloride ions. Thus, rusting of steel fibers stops at the top surface and does
not spread deeper into the concrete. However, steel fibers expand by 30% of its original volume
due to rusting, but due to the smaller size of the steel fibers, this increase in the volume of the steel
fibers is not adequate to produce substantial internal stress to cause spalling of UHPC. Hence, at
serviceability conditions, the possibility of rusting of the internal steel fibers is insignificant (Voo,
2006).
2.2.1.1.9 Cost of UHPC Production
Although UHPC possess higher compressive and tensile capacity, it has been used in a very limited
application. The United States has only very few large-scale UHPC bridge girders. The governing
factor which overshadows the extensive use of UHPC is its high cost and limited available research
data. The cost of UHPC is almost ten times more than the cost of conventional concrete per unit
volume (Homeland Security Science and Technology 2010). The principal governing factors for
the cost of UHPC is its high cost of production and quality control, lack of industry knowledge,
undeveloped standards and design codes which preclude its extensive usages in more common
engineering applications. In order to increase the mass production and cost effective use of the
material, performance based design and optimization of UHPC structural members are highly
essential and demands further research such as; (a) Elimination of shear reinforcement to attain
maximum flexural capacity; (b) optimization of section; (c) Different types of fiber orientation
affecting strength; (c) applicability of existing traditional concrete models for cracking and post-
cracking behavior of UHPC; (d) applicability and accuracy of existing methods of predicting shear
and flexural resistance of UHPC.
2.2.2 Reinforcement
Since concrete is weak in tension, reinforcements are provided to resist the tensile stresses to avoid
cracking as discussed earlier. Basically, a concrete structure can be reinforced by either continuous
or discontinuous types of reinforcement. Since the section 2.2.1.1.3 explained steel fibers
(discontinuous) reinforcement types in detail, the present section discusses only longitudinal
(continuous) reinforcement type. And, the most popular and traditional material for longitudinal