The document discusses the design and construction of composite bridge piers made of steel pipes and concrete. Experimental tests on scaled pier models showed that the composite piers had higher deformation performance and more stable seismic behavior than conventional reinforced concrete hollow piers. The composite piers exceeded maximum deformation but had relatively small residual displacement after earthquakes. The analytical models of composite piers showed lower deformation performance than experimental results because they could not account for the contribution of ductile steel pipes and high-strength strands. A new construction method called Hybrid Slipform Method provides rapid construction and reduced labor for the composite piers.
Concrete filled steel tubes subjected to axial compressioneSAT Journals
Abstract Concrete-filled steel tubular columns have excellent earth-quake resistant properties such as high strength and ductility and large energy absorption capacity. For concrete-filled steel tubes (CFST), local buckling commonly observed in bare steel columns is effectively prevented, giving a higher capacity. However if the concrete core and the steel tube are loaded simultaneously the steel tube expands more than the concrete core under moderate loads since Poisson’s ratio is higher for the steel section. The objective of this paper is To evaluate the accuracy of codal design approach by comparing experimental results with the analytical results obtained using EC4, ACI-318 and AISC-LRFD, for prediction of load carrying capacity of CFST columns under axial compression. Based on this the experimental programme is conducted on concrete filled steel tubes of length 300mm, thickness 1 to 3mm for circular, square and rectangular cross section with three different grades of concrete.200 T capacity Compression testing machine is used for experimental investigation.. The experimental results are compared with analytical results obtained by stated code of practices. From this it is concluded that EC4 gives conservative results. From which it is observed that EC4 gives conservative results with experimental results and it is concluded that EC4 provisions may be used for further analytical study to develop an expression to predict the section capacity CFST columns. As the grade of concrete increases the load carrying capacity is also increases. This paper presents the details of study carried out and the conclusions arrived. Keywords: CFST, high strength, local buckling, analytical, ACI-318, EC4, AISC-LRFD.
Finite element analysis of innovative solutions of precast concrete beamcolum...Franco Bontempi
Especially to precast concrete structure connections are one of the most essential parts. Connections transfer forces between precast members, so the interaction between precast units is obtained. They are generally the
weakest link in the structure. An acceptable performance of precast concrete structure depends especially on the
appropriate kind of connections choice, adequate detailing of components and design of the connections is fundamental. It is interesting to study the behavior of connecting elements and to compare different solutions of ductile connections for precast concrete structures in case of horizontal applied force and vertical imposed displacement, as well as those produced by hazards situation, like that earthquake and explosion, whereby topics of structure robustness are carried out. The case of study is an innovative dissipative system of connection between precast concrete elements, usable for buildings and bridges, the investigation of these topics is carried out by F.E.A. by program DIANA with comparison with results obtained independently with ASTER.
Concrete filled steel tubes subjected to axial compressioneSAT Journals
Abstract Concrete-filled steel tubular columns have excellent earth-quake resistant properties such as high strength and ductility and large energy absorption capacity. For concrete-filled steel tubes (CFST), local buckling commonly observed in bare steel columns is effectively prevented, giving a higher capacity. However if the concrete core and the steel tube are loaded simultaneously the steel tube expands more than the concrete core under moderate loads since Poisson’s ratio is higher for the steel section. The objective of this paper is To evaluate the accuracy of codal design approach by comparing experimental results with the analytical results obtained using EC4, ACI-318 and AISC-LRFD, for prediction of load carrying capacity of CFST columns under axial compression. Based on this the experimental programme is conducted on concrete filled steel tubes of length 300mm, thickness 1 to 3mm for circular, square and rectangular cross section with three different grades of concrete.200 T capacity Compression testing machine is used for experimental investigation.. The experimental results are compared with analytical results obtained by stated code of practices. From this it is concluded that EC4 gives conservative results. From which it is observed that EC4 gives conservative results with experimental results and it is concluded that EC4 provisions may be used for further analytical study to develop an expression to predict the section capacity CFST columns. As the grade of concrete increases the load carrying capacity is also increases. This paper presents the details of study carried out and the conclusions arrived. Keywords: CFST, high strength, local buckling, analytical, ACI-318, EC4, AISC-LRFD.
Finite element analysis of innovative solutions of precast concrete beamcolum...Franco Bontempi
Especially to precast concrete structure connections are one of the most essential parts. Connections transfer forces between precast members, so the interaction between precast units is obtained. They are generally the
weakest link in the structure. An acceptable performance of precast concrete structure depends especially on the
appropriate kind of connections choice, adequate detailing of components and design of the connections is fundamental. It is interesting to study the behavior of connecting elements and to compare different solutions of ductile connections for precast concrete structures in case of horizontal applied force and vertical imposed displacement, as well as those produced by hazards situation, like that earthquake and explosion, whereby topics of structure robustness are carried out. The case of study is an innovative dissipative system of connection between precast concrete elements, usable for buildings and bridges, the investigation of these topics is carried out by F.E.A. by program DIANA with comparison with results obtained independently with ASTER.
Effect of depth to thickness ratio and length to depth ratio on hollow sectio...eSAT Publishing House
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
The Performance Evaluation of Concrete Filled Steel Tubular Arch BridgeIJERA Editor
In this paper, the system assessment theory of he concrete filled steel tubular arch bridge which is based on the theory of the reliability of system reliability is researched through the finite element analysis software ANSYS. Because the concrete filled steel tube arch bridge has the characteristics, such as the components numerous, complex forces, unable to list the of the explicit limit state equation, so use the probability design module of ANSYS (PDS) technology for the performance evaluation of the concrete filled steel tubular arch bridge with the combination of the reliability theory of monte carlo (MC) method, the response surface method (RSM) and the equivalent normal distribution method (JC method).According to the measured data and documents, selecte the random variables which have a large influence on structure reliability as the input parameters and use APDL language to write the structural response’s parameterized model of concrete filled steel tubular arch bridge. Then fit the response surface equation and get its statistical sampling parameters, and finally using Matlab program based on JC method to calculate the reliability index of the components. According to the structure characteristics of concrete filled steel tube arch bridge, the whole structure is as a series of arch rib series, derrick, floor system, selection of components of the minimum reliability index as the system's reliability index.
comparative study of steel I - girder and prestressed steel I - girder as per...Dr. Dhara shah
Prestressing of structural elements especially steel girders improve their load bearing capacity and rigidity along
with reduction in material consumption and overall cost for the same loading. The present study aims at preparing
expedient interface for design of Steel I-Girder and Prestressed Steel I-Girder as per IRC24: 2010, encompassed through
parametric study of two lane road bridges for varying span to depth ratios, considering 15m, 20m, 25m and 30m of spans.
The analysis is done considering dead load, superimposed load and moving load as per class A-2 lane / class 70R loading.
Design of prestressed steel I-girder is done by varying the diameter and number of strands. 9.5 mm, 11.1 mm, 12.7 mm and
15.2 mm diameter class B 7-ply strands are considered in 4, 8, 12, 16 and 20 numbers of groups. The cost comparison is
done as per prevailing market rates. A definite increase in the bending capacity of steel I-girder is found when prestressed
with strands, without any enhancement in shear capacity. Prestressed steel I-girder provides shallower depth of the girder
for same L/D ratio. With increase in the strand area and number of strands, bending capacity increases for same L/D ratio.
Prestressed steel I- girder shows cost saving up to 50% for 15m span, 37% for 20m span, 28% for 25m span and 20% for
30m span. Cost of girder per meter length decreases when applying the prestressing force with increase in L/D ratio.
FINITE ELEMENT ANALYSIS OF INNOVATIVE SOLUTIONS OF PRECAST CONCRETE BEAM-COLU...Franco Bontempi
Especially to precast concrete structure connections are one of the most essential parts. Connections transfer forces between precast members, so the interaction between precast units is obtained. They are generally the
weakest link in the structure. An acceptable performance of precast concrete structure depends especially on the
appropriate kind of connections choice, adequate detailing of components and design of the connections is fundamental. It is interesting to study the behavior of connecting elements and to compare different solutions of ductile connections for precast concrete structures in case of horizontal applied force and vertical imposed displacement, as well as those produced by hazards situation, like that earthquake and explosion, whereby topics of structure robustness are carried out. The case of study is an innovative dissipative system of connection between precast concrete elements, usable for buildings and bridges, the investigation of these topics is carried out by F.E.A. by program DIANA with comparison with results obtained independently with ASTER.
The effect of varying span on Design of Medium span Reinforced Concrete T-bea...theijes
Bridge is a structure providing passageway over an obstacle without closing the way beneath. T-beam Bridge is mainly used by designer for small and medium span bridge. Reinforced Concrete is mostly used for highway bridge construction because of its durability, rigidity, economy, ease of construction and ease with pleasing appearance. This paper describes the design of 4-lane Reinforced Concrete T-beam Bridge deck considering IRC Class-AA tracked loading with span varying from 25 to 40m. After computing manually and STAAD Pro analysis software, it is observed that dead load bending moment with increasing span increases almost square of span
Reduction of Ultimate Strength due to Corrosion - A Finite Element Computatio...CSCJournals
Bridge safety is of paramount importance in transportation engineering and maintenance management. Corrosion causes strength deterioration and weakening of aged steel structures. Therefore, it is a vital task to estimate the remaining strength of corroded steel structures in order to assure the public safety. Due to the economic constraints and increase of number of steel highway and railway bridge structures, it will be an exigent task to conduct tests for each and every aged bridge structure within their bridge budgets. Therefore, this paper proposes a method of evaluating the residual strength capacities by numerical approach and compares the non-linear FEM analyses results with their respective tensile coupon tests. Further, since it is not easy to measure several thousands of points, to accurately reproduce the corroded surface by numerical methods and to predict their yield and ultimate behaviors, a simple and reliable analytical model is proposed by measuring the maximum corroded depth (tc,max), in order to estimate the remaining strength capacities of actual corroded members more precisely.
15 experimental study for strengthening of rc rectangular columns with anchor...Ahmed Ebid
Debonding between CFRP sheets and concrete surface is one of the most important modes of failure. The common solution to
prevent this mode of failure is to extend the CFRP sheets by enough length to avoid debonding. A more advanced technique is to anchor the CFRP sheets to the concrete element using either steel or CFRP anchors. The aim of this research is to study the effect of using CFRP anchors on the capacity of concentric and eccentric RC columns. In order to achieve that goal, ten specimens of RC columns divided into two sets were tested. The first set was tested under concentric load, while the other set was tested under eccentric load. Each set had one control sample, while the other four samples were wrapped with CFRP bands. Two of the wrapped samples were anchored and the others were not. The spacing between CFRP wraps was varied between 80 and 200 mm. The results showed that the concentric and eccentric capacity of the sample increased with decreasing the spacing between CFRP bands as long as the eccentricity is small enough to cause
compression failure mode. But for samples with tension failure caused by large eccentricity, the CFRP bands have no effect on the capacity. It was also noted that anchors have no significant effect on the axial capacity of the samples
Finite Element analysis of a hybrid RCS beam-column connectionQuang Huy Nguyen
A new type of exterior RCS connection, in which a steel prole totally embedded inside RC
column is directly welded to the steel beam, is recently proposed within European RCFS
project SMARTCOCO. This kind of joint detail is not covered by the existing design
guidelines. Indeed, Eurocodes 2, 3 and 4 give some provisions that can partly be used for
the design of such a joint. There remains however a real lack of knowledge relatively to the
issue of the force transmission from the embedded steel prole to the surrounding concrete
of the column. Questions that can rise when designing such a connection are about the
optimal anchorage length to embed the steel prole or about the design of reinforcements
in the connection zone of the RC column and in the transition zone at each end of the
embedded steel prole. Based on Eurocodes and existing research works in the literature,
a design method is proposed within European RCFS project SMARTCOCO. However,
experimental tests and numerical simulations need to be conducted to valid this method.
This paper deals with nonlinear nite element model for this type of exterior RCS beamcolumn
connection. The material nonlinearities of concrete, steel beam, stud and rebar
are included in the nite element model. Four RCS joints with dierent anchorage lengths
and concrete classes are modeled. The failure modes and loads are analyzed and compared
to the predicted ones of the design model.
The Performance Evaluation of Concrete Filled Steel Tubular Arch BridgeIJERA Editor
In this paper, the system assessment theory of he concrete filled steel tubular arch bridge which is based on the theory of the reliability of system reliability is researched through the finite element analysis software ANSYS. Because the concrete filled steel tube arch bridge has the characteristics, such as the components numerous, complex forces, unable to list the of the explicit limit state equation, so use the probability design module of ANSYS (PDS) technology for the performance evaluation of the concrete filled steel tubular arch bridge with the combination of the reliability theory of monte carlo (MC) method, the response surface method (RSM) and the equivalent normal distribution method (JC method).According to the measured data and documents, selecte the random variables which have a large influence on structure reliability as the input parameters and use APDL language to write the structural response’s parameterized model of concrete filled steel tubular arch bridge. Then fit the response surface equation and get its statistical sampling parameters, and finally using Matlab program based on JC method to calculate the reliability index of the components. According to the structure characteristics of concrete filled steel tube arch bridge, the whole structure is as a series of arch rib series, derrick, floor system, selection of components of the minimum reliability index as the system's reliability index.
Effect of depth to thickness ratio and length to depth ratio on hollow sectio...eSAT Publishing House
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
The Performance Evaluation of Concrete Filled Steel Tubular Arch BridgeIJERA Editor
In this paper, the system assessment theory of he concrete filled steel tubular arch bridge which is based on the theory of the reliability of system reliability is researched through the finite element analysis software ANSYS. Because the concrete filled steel tube arch bridge has the characteristics, such as the components numerous, complex forces, unable to list the of the explicit limit state equation, so use the probability design module of ANSYS (PDS) technology for the performance evaluation of the concrete filled steel tubular arch bridge with the combination of the reliability theory of monte carlo (MC) method, the response surface method (RSM) and the equivalent normal distribution method (JC method).According to the measured data and documents, selecte the random variables which have a large influence on structure reliability as the input parameters and use APDL language to write the structural response’s parameterized model of concrete filled steel tubular arch bridge. Then fit the response surface equation and get its statistical sampling parameters, and finally using Matlab program based on JC method to calculate the reliability index of the components. According to the structure characteristics of concrete filled steel tube arch bridge, the whole structure is as a series of arch rib series, derrick, floor system, selection of components of the minimum reliability index as the system's reliability index.
comparative study of steel I - girder and prestressed steel I - girder as per...Dr. Dhara shah
Prestressing of structural elements especially steel girders improve their load bearing capacity and rigidity along
with reduction in material consumption and overall cost for the same loading. The present study aims at preparing
expedient interface for design of Steel I-Girder and Prestressed Steel I-Girder as per IRC24: 2010, encompassed through
parametric study of two lane road bridges for varying span to depth ratios, considering 15m, 20m, 25m and 30m of spans.
The analysis is done considering dead load, superimposed load and moving load as per class A-2 lane / class 70R loading.
Design of prestressed steel I-girder is done by varying the diameter and number of strands. 9.5 mm, 11.1 mm, 12.7 mm and
15.2 mm diameter class B 7-ply strands are considered in 4, 8, 12, 16 and 20 numbers of groups. The cost comparison is
done as per prevailing market rates. A definite increase in the bending capacity of steel I-girder is found when prestressed
with strands, without any enhancement in shear capacity. Prestressed steel I-girder provides shallower depth of the girder
for same L/D ratio. With increase in the strand area and number of strands, bending capacity increases for same L/D ratio.
Prestressed steel I- girder shows cost saving up to 50% for 15m span, 37% for 20m span, 28% for 25m span and 20% for
30m span. Cost of girder per meter length decreases when applying the prestressing force with increase in L/D ratio.
FINITE ELEMENT ANALYSIS OF INNOVATIVE SOLUTIONS OF PRECAST CONCRETE BEAM-COLU...Franco Bontempi
Especially to precast concrete structure connections are one of the most essential parts. Connections transfer forces between precast members, so the interaction between precast units is obtained. They are generally the
weakest link in the structure. An acceptable performance of precast concrete structure depends especially on the
appropriate kind of connections choice, adequate detailing of components and design of the connections is fundamental. It is interesting to study the behavior of connecting elements and to compare different solutions of ductile connections for precast concrete structures in case of horizontal applied force and vertical imposed displacement, as well as those produced by hazards situation, like that earthquake and explosion, whereby topics of structure robustness are carried out. The case of study is an innovative dissipative system of connection between precast concrete elements, usable for buildings and bridges, the investigation of these topics is carried out by F.E.A. by program DIANA with comparison with results obtained independently with ASTER.
The effect of varying span on Design of Medium span Reinforced Concrete T-bea...theijes
Bridge is a structure providing passageway over an obstacle without closing the way beneath. T-beam Bridge is mainly used by designer for small and medium span bridge. Reinforced Concrete is mostly used for highway bridge construction because of its durability, rigidity, economy, ease of construction and ease with pleasing appearance. This paper describes the design of 4-lane Reinforced Concrete T-beam Bridge deck considering IRC Class-AA tracked loading with span varying from 25 to 40m. After computing manually and STAAD Pro analysis software, it is observed that dead load bending moment with increasing span increases almost square of span
Reduction of Ultimate Strength due to Corrosion - A Finite Element Computatio...CSCJournals
Bridge safety is of paramount importance in transportation engineering and maintenance management. Corrosion causes strength deterioration and weakening of aged steel structures. Therefore, it is a vital task to estimate the remaining strength of corroded steel structures in order to assure the public safety. Due to the economic constraints and increase of number of steel highway and railway bridge structures, it will be an exigent task to conduct tests for each and every aged bridge structure within their bridge budgets. Therefore, this paper proposes a method of evaluating the residual strength capacities by numerical approach and compares the non-linear FEM analyses results with their respective tensile coupon tests. Further, since it is not easy to measure several thousands of points, to accurately reproduce the corroded surface by numerical methods and to predict their yield and ultimate behaviors, a simple and reliable analytical model is proposed by measuring the maximum corroded depth (tc,max), in order to estimate the remaining strength capacities of actual corroded members more precisely.
15 experimental study for strengthening of rc rectangular columns with anchor...Ahmed Ebid
Debonding between CFRP sheets and concrete surface is one of the most important modes of failure. The common solution to
prevent this mode of failure is to extend the CFRP sheets by enough length to avoid debonding. A more advanced technique is to anchor the CFRP sheets to the concrete element using either steel or CFRP anchors. The aim of this research is to study the effect of using CFRP anchors on the capacity of concentric and eccentric RC columns. In order to achieve that goal, ten specimens of RC columns divided into two sets were tested. The first set was tested under concentric load, while the other set was tested under eccentric load. Each set had one control sample, while the other four samples were wrapped with CFRP bands. Two of the wrapped samples were anchored and the others were not. The spacing between CFRP wraps was varied between 80 and 200 mm. The results showed that the concentric and eccentric capacity of the sample increased with decreasing the spacing between CFRP bands as long as the eccentricity is small enough to cause
compression failure mode. But for samples with tension failure caused by large eccentricity, the CFRP bands have no effect on the capacity. It was also noted that anchors have no significant effect on the axial capacity of the samples
Finite Element analysis of a hybrid RCS beam-column connectionQuang Huy Nguyen
A new type of exterior RCS connection, in which a steel prole totally embedded inside RC
column is directly welded to the steel beam, is recently proposed within European RCFS
project SMARTCOCO. This kind of joint detail is not covered by the existing design
guidelines. Indeed, Eurocodes 2, 3 and 4 give some provisions that can partly be used for
the design of such a joint. There remains however a real lack of knowledge relatively to the
issue of the force transmission from the embedded steel prole to the surrounding concrete
of the column. Questions that can rise when designing such a connection are about the
optimal anchorage length to embed the steel prole or about the design of reinforcements
in the connection zone of the RC column and in the transition zone at each end of the
embedded steel prole. Based on Eurocodes and existing research works in the literature,
a design method is proposed within European RCFS project SMARTCOCO. However,
experimental tests and numerical simulations need to be conducted to valid this method.
This paper deals with nonlinear nite element model for this type of exterior RCS beamcolumn
connection. The material nonlinearities of concrete, steel beam, stud and rebar
are included in the nite element model. Four RCS joints with dierent anchorage lengths
and concrete classes are modeled. The failure modes and loads are analyzed and compared
to the predicted ones of the design model.
The Performance Evaluation of Concrete Filled Steel Tubular Arch BridgeIJERA Editor
In this paper, the system assessment theory of he concrete filled steel tubular arch bridge which is based on the theory of the reliability of system reliability is researched through the finite element analysis software ANSYS. Because the concrete filled steel tube arch bridge has the characteristics, such as the components numerous, complex forces, unable to list the of the explicit limit state equation, so use the probability design module of ANSYS (PDS) technology for the performance evaluation of the concrete filled steel tubular arch bridge with the combination of the reliability theory of monte carlo (MC) method, the response surface method (RSM) and the equivalent normal distribution method (JC method).According to the measured data and documents, selecte the random variables which have a large influence on structure reliability as the input parameters and use APDL language to write the structural response’s parameterized model of concrete filled steel tubular arch bridge. Then fit the response surface equation and get its statistical sampling parameters, and finally using Matlab program based on JC method to calculate the reliability index of the components. According to the structure characteristics of concrete filled steel tube arch bridge, the whole structure is as a series of arch rib series, derrick, floor system, selection of components of the minimum reliability index as the system's reliability index.
System shear connector jakarta digunakan sebagai aplikasi dalam konstruksi bangunan untuk menghasilkan kekuatan coran beton lebih kuat dan stabil sesuai dengan perhitungan engineering civil. Dalam hal ini ada 2 hal perhitungan kekuatan secara umum yaitu kekuatan kelengketan stud pada batang baja sesudah dilas. Dan yang kedua adalah kekuatan stud bolt yang digunakan.
This paper presents a study on flexural behaviour of concrete filled steel tube based on the former
work carried out by Manojkumar. An ANSYS model is developed that can predict the behaviour of concrete
filled steel tube to determine moment carrying capacity at ultimate point for beam Concrete filled steel tube
beams are studied and verified by the finite element program ANSYS against experimental data. The Main
parameters affecting the behaviour and strength of concrete filled beams are geometrical parameters, material
nonlinearities, loading, boundary conditions and degree of concrete confinement. To account for all these
properties ANSYS model is developed. The main parameters varied in analysis study are D/t ratio,
characteristic strength of infilled concrete. The proposed model predicts ultimate moment capacity for CFT
beams. In the numerical analysis, circular and rectangular CFT cross sections are considered using different
grades of concrete. The predicted values are compared with experimental results. Numerical analysis has
shown that for rectangular CFT’s a good confining effect can be provided. Moment capacity results obtained
from the ANSYS model are compared with the values predicted by Lin Han (2004) and different codes such as
AISC-LRFD (1999) and EC4 (1994).
Experimental Testing Of Partially Encased Composite Beam ColumnsIJERA Editor
The past few decades have seen outstanding advances in the use of composite materials in structural
applications. There can be little doubt that, within engineering circles, composites have revolutionized
traditional design concepts and made possible an unparalleled range of new and exciting possibilities as viable
materials for construction.
In addition to the well-known advantages of composite columns, partially encased composite columns offered
simplified beam-to-column connection as well as reduced or omitted shuttering thus achieved more cost
effective construction. Some companies have patented these new types of partially encased composite column
made of light welded steel shapes; moreover, the Canadian Institute of Steel construction CISC has recognized
and codified this type of columns.
In This paper, Partially Encased Composite Beam Columns is introduced; experimental studies are made on five
partially encased beam columns to investigate the behavior of eccentrically loaded partially encased composite
columns using different parameters
Experimental Testing Of Partially Encased Composite Beam ColumnsIJERA Editor
The past few decades have seen outstanding advances in the use of composite materials in structural applications. There can be little doubt that, within engineering circles, composites have revolutionized traditional design concepts and made possible an unparalleled range of new and exciting possibilities as viable materials for construction. In addition to the well-known advantages of composite columns, partially encased composite columns offered simplified beam-to-column connection as well as reduced or omitted shuttering thus achieved more cost effective construction. Some companies have patented these new types of partially encased composite column made of light welded steel shapes; moreover, the Canadian Institute of Steel construction CISC has recognized and codified this type of columns. In This paper, Partially Encased Composite Beam Columns is introduced; experimental studies are made on five partially encased beam columns to investigate the behavior of eccentrically loaded partially encased composite columns using different parameters.
Experimental Evaluation of Fatigue Performance of Steel Grid Composite Deck J...IJERDJOURNAL
ABSTRACT:- The steel grid composite deck is a composite structure made of a concrete slab disposed over a steel grid. The joints of the deck segments precast with regular width can be designed by means of lap-spliced rebar or mechanical connection composed of concrete shear key and bolts. This study intends to evaluate comparatively the fatigue performance with respect to the type of joint based upon the results of fatigue tests conducted on deck specimens equipped with such joints. The evaluation reveals that there is practically no change in the stiffness regardless of the type of joint even after 2 million loading cycles and that the safety and serviceability are secured under cyclic loading since the maximum crack widths remained below the allowable values.
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The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
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Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
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1. 0899
1
Civil Engineering Technology Division of Obayashi Corporation, Tokyo, Japan Email: kato@o-net.obayashi.co.jp
2
Department of Civil Engineering Systems, Kyoto University, Kyoto, Japan
EARTHQUAKE DESIGN AND CONSTRUCTION OF TAL COMPOSITE BRIDGE
PIERS
T KATO1
And Y TAKAHASHI2
SUMMARY
The recent lessons of structural damages occurred to a number of bridges during 1995 Hyogo-ken
Nanbu Earthquake make a new bridge construction more expensive and time consuming because
of the high standard of earthquake resistant design. The new expressway construction (the 2nd
Tomei expressway) mainly crossing over deep valleys requires many tall bridge piers. Therefore it
is required to develop the new technology which takes place of the conventional RC hollow pier.
The new design concept of steel pipe-concrete composite bridge pier exhibits not only high
seismic resistance in effect of ductile steel pipe and spiral high strength strand, but also a rapid
construction method.
In this paper the earthquake design by the scaled model tests as well as the construction practice of
the tall composite bridge pier are described.
The results and conclusions are follows:
The experimental M-Φ relation of the composite piers showed higher deformation performance
than the conventional RC hollow bridge pier.
In pseudo dynamic tests the composite piers had a stable seismic behavior even after the ultimate
state. And although the deformation exceeded maximum peak, the residual displacement after the
earthquake was relatively small.
The analytical moment – curvature relationship of steel pipe – concrete composite piers showed
lower deformation performance than the experimental results. The main reason of the low
performance of the analytical models is due to the ductile steel pipe and high strength spiral strand,
which cannot be coped with in the model. The results show that the contribution of steel pipes to
concrete should be taken into account in order to improve the analytical methods for design.
The new construction method (namely Hybrid Slipform Method) on the composite bridge pier
provides an appropriate solution for rapid construction and reduction of the skilled labor.
INTRODUCTION
After Hyogo-ken Nanbu earthquake the conventional RC hollow high pier needs a large amount of
reinforcement because of high standard of seismic design. Consequently the construction cost as well as the
construction period are serious subjects. The steel pipe - concrete composite pier in Figure 1 exhibits not only
high seismic resistance in effect of ductile steel pipe and spiral high strength strand, but also an advanced
construction method.
The characteristics of the new composite pier are as follows.
a) The composite structure is consist of single vertical re-bars outside and large steel pipes inside.
b) High shear strength is provided by inner steel pipes and high strength strands as spiral hoop. c) High ductility
is provided by steel pipe as well as spiral hoop effect.
d) Concrete around steel pipes protect from buckling. In the case of buckling of outside re-bars at ultimate state,
the collapse would not occur.
e) Simple section makes a better manufacturing than conventional RC hollow section.
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Figure 1: Steel pipe-concrete composite pier
STATIC EXPERIMENTAL STUDY OF COMPOSITE PIER
Specimen (test piece)
In order to verify the inelastic behavior of composite piers under the combined loads, static loading tests and
pseudo dynamic tests were carried out. Five composite column models were tested, as shown Figure 2 - 4 and
Table 1. The each shear spans are 1200mm and 600mm, the each shear span ratios are 4.0 and 2.0. As shown
Figure 4, 4 pipes (diameter 76.3mm, thickness 2.8mm) and 8 re-bar (diameter 10mm) are installed in the section.
Table 1 : Test Specimens
No. Experiment
Shear span ratio
a/d
Axial load
(N/mm2
)
Steel pipe
ratio Pt (%)
Re-bar
Ratio Pr (%)
Spiral strand
ratio Peq (%)
P4-1 Static 4.0 3.5 2.53 0.56 0.18
P4-2 Pseudo dynamic 4.0 3.5 2.53 0.56 0.18
P4-3 Pseudo dynamic 4.0 3.5 2.53 0.56 0.18
P2-1 Static 2.0 3.5 2.53 0.56 0.18
P2-2 Static 2.0 3.5 2.53 0.56 0.18
Steel pipe
Spiral strand re-barre-bar
Concrete
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Figure 2: Section of Specimen
Figure 3: P4-1-3 Specimens Figure 4: P2-1-2 Specimens
Experimental system
Figure 5 shows the experimental system. Lateral load is given under the fixed axial load. At the loading point
lateral sift and rotation are free. The axial load is 3.5 N/mm2
.
Figure 5: Experimental system
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Static loading tests
1) Static loading tests for shear span ratio of 4.0(flexure failure test)
Figure 6 shows load - displacement relation. The relation curve is deteriorating from the maximum loading to the
ultimate state. Thus deteriorating mechanism a typical property of this composite structure by the effect of bond
slip between concrete and steel pipe. The maximum ductility factor is 7.5 superior to RC structure in general.
2) Static loading tests for shear span ratio of 2.0(shear failure test)
Figure 7 shows load - displacement relationship. The relation curve is gradually deteriorating like a flexure
failure in spite of shear failure test because of shear strength of steel pipe. This result shows that the tested
composite column has a high ductility and the shear strength of steel pipe should be taken account in structural
design.
Figure 6: Load-disp. Relation (P4-1) Figure 7: Load-disp. Relation (P2-1)
Pseudo dynamic tests
In static loading test, the structural the basic property as loading and deformation capacity can be estimate, but
the dynamic behavior of structures is not considered. Therefore the pseudo dynamic tests were carried out for the
purpose as follows,
a) to observe damage level and residual displacement of composite pier directly and to estimate seismic stability
b) to compare the M-Φ property of composite pier with analytical model directly
The experimental model has a single degree of freedom with natural period of 2.0s considering actual viaduct
with high pier. Moderate Kaihoku LG(Miyagi-ken Oki Earthquake 1978) and Kobe NS(Hyougo-ken Nanbu
Earthquake 1995) which were inputted as shown Figure 8 and Figure 9.
The result of experiment is shown in Table 2. Although the maximum ductility factor exceeded 9.0 for each
earthquake and then the covered concrete fell down, it was confirmed that the test piece of composite pier had
stable seismic behavior and never been collapsed by shear failure. In addition, the residual displacement after the
earthquake was relatively smaller than nonlinear analysis shown Figure 10 and 11. The experimental M-φ
relation of the composite piers showed higher deformation performance than the analytical results as shown
Figure 12 and 13. The main reason of the low performance of the analytical model is due to the property of the
ductile steel pipe and high strength spiral strand, which can not be coped with in the model. This result show that
the contribution of steel pipes to concrete should be taken account in order to improve the analytical models for
rational design.
Figure 8: Earthquake acceleration of Kaihoku LG Figure 9: Earthquake acceleration of Kobe NS
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Table 2: Results of pseudo dynamic tests
Specimen
No.
Earthquake
Inputted
scale
Max.inputted
acc. (gal)
Max.response
acc. (gal)
Max.ductility
factor
Residual
Disp. (mm)
P4-3
Type-Ⅰ
Kaihoku
18 % 57.4 28.6 9.6 1.1
P4-2
Type-Ⅱ
Kobe
18 % 146.2 31.5 9.7 12.1
Figure 10: Comparison between pseudo dynamic test of P4-3
Figure 11: Comparison between pseudo dynamic test of P4-2
Figure 12: Load-disp. Relation of P4-3
Figure 13: Load-disp. Relation of P4-2
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TYPICAL CONSTRUCTION METHOD OF COMPOSITE PIER
The design of a conventional reinforced concrete pier may be an appropriate solution in terms of material
efficiency and cost, while the overall construction cost as well as the construction period may not be optimum.
The left hand side of Figure 14 shows a typical configuration of the conventional hollow type structure, which
have one- or two-boxes. The right hand side of Figure 14 illustrates a typical cross section of the composite
design, which is constructed by the steel pipes and the minimum amount of reinforcement.
A long term social trend in labor market is the shortage of skilled labor and the decrease of annual working
hours. This trend enhances the engineering development for a drastic improvement of construction time and
labor force required for the bridge construction. The goal of new construction method is one half in construction
time and one third in labor input compared to the conventional design and jump-form construction. Figure 15
illustrates the equipment and structural arrangements of the new method.
A. Conventional hollow B. Composite
Figure 14: Structural concept of conventional and composite alternative
Figure 15: Illustration of Structural system and equipment of Hybrid-slipform method
The construction sequence of the method in described in Figure 16. The first step of construction is the erection
of prefabricated segment of steel pipes, which length is about 10m each. Those erected steel pipes have the
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structural stability against the wind load till the concrete pour. At every 10m of the pipe segment erection, the
group of steel pipes is strengthened by bracing, connecting each pipe together. When the erection reached to the
pier top, a reaction frame is installed and fastened at the pipe head. The reaction frame supports the vertical
slipforming load transmitted through the vertical tension wires made of the standard strands.
The second step follows the assembly of slipform, working decks, scaffold and jacking system(8 center hole
jacks). The slipform system has four working decks. The top deck has a loop of rail track where the automated
pc strand feeder runs on the track. The main deck is used for the jobs of formwork, re-bar installation,
concerning and jack operation. The lower decks are for the removal of Sheet-in-Form and the work of concrete
curing. In stead of a sophisticated computer control for jacking system, the manual operation is used to lifts the
scaffold up 2.7m every day.
Once completed the slipform installation, the highlight of Hybrid-Slipform Method begins with the pier
construction by the daily repetition of jobs sequence. The cycle consists of the jack up of the slipform system,
the spiral strand installation, the placement of form, the concrete work. The height of concrete placed by each
daily cycle is planned to be 2.7m. (as shown Figure 17)
The old sheet-in-form persists its position and remained to the old position of concrete poured one day before.
As soon as the scaffold is settled to the new position, the new sheet-in-form is placed for the next concrete
pouring. The advantages of utilization of the sheet-in-form are significant : a smooth surface finish of concrete
as same as the fixed form, a drastic change of the slipforming procedure from continuous from lifting to at once
lifting at any time, a better curing protection to the concrete surface, and more easier positioning of the
slipform.(as shown Figure 18)
The horizontal reinforcement of spiral high strength strand is spiraled along the vertical reinforcement by using
the automated strand feeder. The placement takes one and half hours by a few workers, which is needed for
fastening the strands to the vertical re-bars. When the slipform reached to the fine elevation of pier structure, the
working decks and scaffolds are easily lifted down together to the ground by the reversal use of jacking system.
During the down ward process, any necessary finishing job for the concrete surface of pier can be done by using
the working decks. (as shown Figure 19)
Practical design and construction of the composite piers are now under construction in the 2nd Tomei Project and
so on. This area is mountainous and crossing deep valleys.
(1) Erection of steel pipe &
welding
(2) Set of slipform & spiral
strand feeder
(3) Concrete construction
by slipforming
(4) Lift-down of slipform
scaffold after completion
Figure 16: Construction Procedure of Hybrid-Slipform Method
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Figure 17: Hybird-Slipform method construction
Figure 18: Installation of sheet-in-form Figure 19: Automated sPIral strand feeder
CONCLUSIONS AND REMARKS
The steel pipe-concrete composite pier and its suitable construction method (namely Hybrid-slipform Method)
provides an appropriate solution not only for ductile structural performance, but also rapid construction suitable
for the tall bridge pier particularly in a highly seismic region.
In pseudo dynamic tests the composite piers had a stable seismic behavior even after the ultimate state. And
although the deformation exceeded maximum peak, the residual displacement after the earthquake was relatively
small.
ACKNOWLEDGEMENTS
The authors would like to express their deep appreciation to Japan Highway Public Corporation(Nihon Doro
Kodan).
REFERENCES
1. Iemura,H., Kato,T. and Kawatani,S.(1982):Hybrid Experiment on Earthquake Response of Original
and Repaired RC members, Proc. 6th Japan Earthquake Engineering Symposium, pp825-832
2. Iemura,H., Kato,T. and Takahashi,Y.(1998):Experimental Studies on Seismic Performance of Steel
pipe-concrete Composite Pier, Proc. 10th Japan Earthquake Engineering Symposium, pp2105-2110
3. Iemura,H.(1980):Failure Criteria of Deteriorating Hysteretic Structures,Proc. of The 7th World
Conference on Earthquake engineering ,PP.81-88
4. Iemura,H., Yamada,Y. and Tanzo,W. (1988):Testing R/C Specimens by a Substructure - Based Hybrid
Earthquake Loading System, Proc. of The 7th World Conference on Earthquake engineering