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.
ENHANCED FERROCEMENT JACKETS FOR STRENGTHENING LONG REINFORCED CONCRETE COLUMNS IAEME Publication
Strengthening slender reinforced concrete (RC) columns is a challenge because
their sensitivity to overall buckling and the combination of the bending and
compressive stresses. This paper presents experimental study for strengthening twenty
long RC columns using enhanced ferrocement jackets. The column specimens have
slenderness ratio of 17.6 and two different cross-sections (square and rectangular).
The utilized expanded metal mesh layers have different weights, lengths and numbers
for each jacket. The twenty strengthened specimens and four reference non-jacketed
specimens were tested under concentric compression loading. The results
demonstrated the effectiveness of the ferrocement jacket in improving the column
capacity, increasing the stiffness, and reducing the lateral deformation. The
significance of the jackets is more evident for long RC columns with larger crosssection area, and for jackets with larger volume fraction of metal mesh layers at the
middle-third of the column height.
Flexural behavior of composite reinforced concrete t beams cast in steel cha...IAEME Publication
The document summarizes an experimental study on the flexural behavior of composite reinforced concrete T-beams with horizontal transverse bars as shear connectors. Three large-scale beam specimens were fabricated, loaded until failure, and their load-deflection responses were measured. Results showed that beams with horizontal bar shear connectors had substantially higher ultimate bending capacity, flexural stiffness, and integrity compared to previous studies using headed stud connectors. The use of horizontal bars as shear connectors provides improved flexural performance of composite concrete beams cast in steel channels.
IRJET- Effects of Different Parameters on Inelastic Buckling Behavior of ...IRJET Journal
This document discusses a study that analyzed the buckling behavior of composite concrete-filled steel tube columns with different parameters. The study used finite element analysis to model composite columns with double I-beam cross sections. It investigated the effects of eccentric loading, slenderness ratio, and distance between steel profiles on buckling capacity. The results showed that filling steel sections with concrete delays steel yielding and increases column capacity. Greater concrete surface area and lower slenderness ratio also led to higher strength due to increased confinement effects.
The purpose of the experimental work presented in this study is to study the effect
of concrete compressive strength and steel reinforcement ratio on capacity and
deflection of reinforced concrete two-way slabs. Three steel reinforcement ratios are
considered which are minimum, maximum and average of them in addition to two
concrete compressive strength
values of 20 and 30 MPa. The results from
experimental work show that increasing the reinforcing steel ratio leads to increase the
ultimate capacity of the slab in addition to decrease the maximum deflection. For slabs
with
= 20 MPa, increasing the reinforcing steel ratio from the minimum to the
maximum, i.e. 600 %, leads to increase ultimate capacity by about 156 % and decrease
maximum deflection by about 52 %. Wheras, For slabs with
= 30 MPa, increasing
the reinforcing steel ratio from the minimum to the maximum, i.e. 900 %, leads to
increase ultimate capacity by about 155 % and decrease maximum central deflection
by about 27 %. In addition, matmatical expresions for load-deflection relationships are
presented in the current study
Experimental Study on Flexural Behaviour of Steel Beam at Diverse LoadingIRJET Journal
This study experimentally analyzed the flexural behavior of steel channel sections (ISMC75) under different loading conditions. The channel section was tested as a simply supported beam under two-point loading applied at either the web or flange. When loaded at the flange, the channel section carried 47% higher loads than when loaded at the web, reaching its plastic moment capacity. Deflections were also higher under flange loading. The results provide data on the flexural behavior and load-carrying capacity of channel sections based on the point of load application.
The document summarizes a numerical study on the behavior of concrete-filled steel tube columns under axial loads. A finite element model was developed using ABAQUS to simulate the composite action between the steel tube and concrete core. The model considers the nonlinear stress-strain behavior of confined concrete and elastic-plastic behavior of steel. The results of the model were validated by comparing ultimate loads to experimental data, with a maximum difference of 5-10%. Analytical calculations from codes like ACI and Eurocode were also compared to the experimental and numerical ultimate loads.
Parametric Study of Square Concrete Filled Steel Tube Columns Subjected To Co...IJERA Editor
The Concrete Filled Steel Tube (CFST) member has many advantages compared with the conventional concrete structural member. This study presents on the behaviour of concrete-filled steel tube (CFST) columns under axial load by changing parameters. The parameters are thickness of steel tube, Grade of concrete and length of column. The study was conducted using ANSYS 13 finite element software. All the columns are 60 X 60 mm in size. The thickness of the tube is taken as 2, 3, 4, 5 and 6 mm for thickness variation. The grades of concrete infill are M25, M30, M40, M50, M60 and M70 used for grade variation. Lengths of columns are taken as 900, 1200, 1500, 1800, 2100, and 2400 mm for length variation. Buckling load is compared with Euro code 4 (1994).
IRJET - Analysis and Design of Steel Box Girder Bridge using Tekla StructuresIRJET Journal
This document presents the analysis and design of a steel box girder bridge with four different cross-sectional models using Tekla Structures software. The models include a single cell, double cell, triple cell, and multi-cell steel box girder bridge. The bridges are designed for a highway loading according to IRC specifications and codes. The models are analyzed under dead loads, live loads, and other load combinations. Results show that bending moments and stresses increase with more cells in the cross-section. The single cell box girder results in the lowest bending moment, requiring less steel and providing the most economical cross-section compared to the other multi-cell options when loading and support conditions are kept the same.
ENHANCED FERROCEMENT JACKETS FOR STRENGTHENING LONG REINFORCED CONCRETE COLUMNS IAEME Publication
Strengthening slender reinforced concrete (RC) columns is a challenge because
their sensitivity to overall buckling and the combination of the bending and
compressive stresses. This paper presents experimental study for strengthening twenty
long RC columns using enhanced ferrocement jackets. The column specimens have
slenderness ratio of 17.6 and two different cross-sections (square and rectangular).
The utilized expanded metal mesh layers have different weights, lengths and numbers
for each jacket. The twenty strengthened specimens and four reference non-jacketed
specimens were tested under concentric compression loading. The results
demonstrated the effectiveness of the ferrocement jacket in improving the column
capacity, increasing the stiffness, and reducing the lateral deformation. The
significance of the jackets is more evident for long RC columns with larger crosssection area, and for jackets with larger volume fraction of metal mesh layers at the
middle-third of the column height.
Flexural behavior of composite reinforced concrete t beams cast in steel cha...IAEME Publication
The document summarizes an experimental study on the flexural behavior of composite reinforced concrete T-beams with horizontal transverse bars as shear connectors. Three large-scale beam specimens were fabricated, loaded until failure, and their load-deflection responses were measured. Results showed that beams with horizontal bar shear connectors had substantially higher ultimate bending capacity, flexural stiffness, and integrity compared to previous studies using headed stud connectors. The use of horizontal bars as shear connectors provides improved flexural performance of composite concrete beams cast in steel channels.
IRJET- Effects of Different Parameters on Inelastic Buckling Behavior of ...IRJET Journal
This document discusses a study that analyzed the buckling behavior of composite concrete-filled steel tube columns with different parameters. The study used finite element analysis to model composite columns with double I-beam cross sections. It investigated the effects of eccentric loading, slenderness ratio, and distance between steel profiles on buckling capacity. The results showed that filling steel sections with concrete delays steel yielding and increases column capacity. Greater concrete surface area and lower slenderness ratio also led to higher strength due to increased confinement effects.
The purpose of the experimental work presented in this study is to study the effect
of concrete compressive strength and steel reinforcement ratio on capacity and
deflection of reinforced concrete two-way slabs. Three steel reinforcement ratios are
considered which are minimum, maximum and average of them in addition to two
concrete compressive strength
values of 20 and 30 MPa. The results from
experimental work show that increasing the reinforcing steel ratio leads to increase the
ultimate capacity of the slab in addition to decrease the maximum deflection. For slabs
with
= 20 MPa, increasing the reinforcing steel ratio from the minimum to the
maximum, i.e. 600 %, leads to increase ultimate capacity by about 156 % and decrease
maximum deflection by about 52 %. Wheras, For slabs with
= 30 MPa, increasing
the reinforcing steel ratio from the minimum to the maximum, i.e. 900 %, leads to
increase ultimate capacity by about 155 % and decrease maximum central deflection
by about 27 %. In addition, matmatical expresions for load-deflection relationships are
presented in the current study
Experimental Study on Flexural Behaviour of Steel Beam at Diverse LoadingIRJET Journal
This study experimentally analyzed the flexural behavior of steel channel sections (ISMC75) under different loading conditions. The channel section was tested as a simply supported beam under two-point loading applied at either the web or flange. When loaded at the flange, the channel section carried 47% higher loads than when loaded at the web, reaching its plastic moment capacity. Deflections were also higher under flange loading. The results provide data on the flexural behavior and load-carrying capacity of channel sections based on the point of load application.
The document summarizes a numerical study on the behavior of concrete-filled steel tube columns under axial loads. A finite element model was developed using ABAQUS to simulate the composite action between the steel tube and concrete core. The model considers the nonlinear stress-strain behavior of confined concrete and elastic-plastic behavior of steel. The results of the model were validated by comparing ultimate loads to experimental data, with a maximum difference of 5-10%. Analytical calculations from codes like ACI and Eurocode were also compared to the experimental and numerical ultimate loads.
Parametric Study of Square Concrete Filled Steel Tube Columns Subjected To Co...IJERA Editor
The Concrete Filled Steel Tube (CFST) member has many advantages compared with the conventional concrete structural member. This study presents on the behaviour of concrete-filled steel tube (CFST) columns under axial load by changing parameters. The parameters are thickness of steel tube, Grade of concrete and length of column. The study was conducted using ANSYS 13 finite element software. All the columns are 60 X 60 mm in size. The thickness of the tube is taken as 2, 3, 4, 5 and 6 mm for thickness variation. The grades of concrete infill are M25, M30, M40, M50, M60 and M70 used for grade variation. Lengths of columns are taken as 900, 1200, 1500, 1800, 2100, and 2400 mm for length variation. Buckling load is compared with Euro code 4 (1994).
IRJET - Analysis and Design of Steel Box Girder Bridge using Tekla StructuresIRJET Journal
This document presents the analysis and design of a steel box girder bridge with four different cross-sectional models using Tekla Structures software. The models include a single cell, double cell, triple cell, and multi-cell steel box girder bridge. The bridges are designed for a highway loading according to IRC specifications and codes. The models are analyzed under dead loads, live loads, and other load combinations. Results show that bending moments and stresses increase with more cells in the cross-section. The single cell box girder results in the lowest bending moment, requiring less steel and providing the most economical cross-section compared to the other multi-cell options when loading and support conditions are kept the same.
This document is a seminar report submitted by Alok B. Rathod for the degree of Master of Technology in Structural Engineering at Bhartiya Vidya Bhavan’s Sardar Patel College of Engineering in Mumbai, India. The report reviews the development of concrete-filled steel tubular structures, including their material properties and behavior under various loads. It summarizes research on their static, dynamic, and fire performance, as well as construction and durability. Design criteria from different codes are examined and examples of CFST applications in buildings, bridges, and other structures are provided.
This document provides a review of steel-concrete composite (SCC) girders under shock loads. SCC construction combines the advantages of steel and concrete by using mechanical shear connectors to bond a steel beam and concrete slab. Under shock loads, SCC girders can experience local failures like concrete crushing or steel buckling. The complex force transfer during shock loading is discussed. Different types of shear connectors are described, and the interface behavior between the steel beam and concrete slab is important to resist shear forces. Both full and partial composite action are examined in terms of flexural capacity under different interaction assumptions. The behavior of SCC girders under shock loading, including dynamic load factors, is also reviewed.
The document provides an overview of corrosion of steel in concrete. It discusses how steel is usually protected from corrosion by the alkaline environment of concrete but can corrode due to carbonation or chloride attack breaking down the protective layer. The corrosion process involves steel dissolving at the anode and oxygen being consumed at the cathode. This leads to a volume increase and the formation of rust, causing cracking and spalling of concrete. It also describes "black rust" that can occur in low-oxygen conditions without visible damage. The document aims to explain the basics of corrosion mechanisms to help understand investigation and repair techniques.
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.
Energy Absorption Characteristics of Thin Walled Metallic and Foam Filled Tub...IRJET Journal
This document discusses a numerical study comparing the energy absorption characteristics of thin-walled metallic tubular structures with different cross-sectional geometries, both empty and foam-filled. Finite element models of circular, triangular, hexagonal and square tubes undergoing quasi-static axial crushing were created and analyzed. The results show that circular tubes absorbed the most energy of the empty metallic tubes, while foam-filled tubes had higher energy absorption than empty tubes of the same geometry.
Buckling of slender composite concrete filled steel columnsRadhwan Faraj
This document summarizes research analyzing test data on 1817 composite concrete-filled steel columns. The test results are compared to calculations according to Eurocode 4 design methods. Several key findings are presented:
1) Test results for circular composite columns generally corresponded well with Eurocode 4 calculations. Test capacities of rectangular columns agreed with calculations when concrete strength was below 75 MPa.
2) Preloading composite members did not influence load-bearing capacity.
3) Analysis of stress distributions, preloading effects, and stress-strain curves was also examined.
4) Test/calculation ratios from the data indicate Eurocode 4 methods are generally conservative, with average ratios above 1.0 for different column types.
This document summarizes analytical studies on concrete filled steel tubes. A finite element model of a rectangular concrete filled steel tube short column was created using ANSYS software. The model was validated against experimental data. Both eigenvalue and nonlinear buckling analyses were performed to determine the ultimate axial load capacity of the column. The eigenvalue analysis provides the theoretical buckling strength, while the nonlinear analysis is more accurate as it considers factors like imperfections and plastic behavior. The results from the ANSYS model were used to develop an approximate formula for calculating the ultimate load of rectangular concrete filled steel tube short columns based on material properties.
This experimental work aims at presenting load-deflection expressions for the
concrete beams that reinforced with three different reinforcement ratios of ACI 318-
14, which are minimum, maximum and the average of them. Three groups of beams
were cast, each group contained three beam specimens. Three types of loading are
used, 1-concentrated force, 2-concentrated forces and partial uniformly distributed
load. It is also seen that, when reinforcing ratio increases from minimum to
maximum, in case of 1-concentrated force, ultimate capacity increases by about 280%
and deflection decreases by about 33%, respectively. Whereas, in case of 2-
concentrated forces, ultimate capacity increases by about 258% and deflection
decreases by about 50%, respectively. Finally, in case of uniformly distributed load,
ultimate capacity increases by about 289% and deflection decreases by about 28%,
respectively.
This document provides an introduction and literature review on concrete filled steel tube (CFST) columns. Some key points:
1) CFST columns utilize the advantages of both steel and concrete by using a steel hollow section filled with concrete. They are widely used in building construction.
2) Previous research has shown CFST columns have improved structural performance due to confinement of the concrete core by the steel tube. They also have construction advantages due to their simple erection sequence.
3) The literature review covers the behavior of CFST under different load cases like axial, bending, and combined loads. It also discusses design concepts, analytical methods, and codes/standards for CFST columns.
This document provides an overview of concrete filled steel tubes (CFT). It discusses the history and components of CFT, how steel tubes confine concrete and improve its properties. Comparisons are made between CFT and steel or reinforced concrete columns. Applications discussed include tall buildings, bridges and the Canton Tower. Advantages of CFT include increased strength and ductility over steel or concrete alone. Limitations relate to limited knowledge of CFT behavior and determining combined properties.
1) The study tested 4 reinforced self-compacting concrete beams to analyze the effect of construction joints on structural performance.
2) The beams included a reference beam without a joint, and beams with horizontal, vertical at mid-span, and vertical at 1/4 span joints.
3) Test results showed construction joints had a more significant effect on ultimate load than first crack load. The horizontal joint beam performed best with a 6.7% reduction in first crack load and 26.7% reduction in ultimate load compared to the reference beam. The vertical 1/4 span joint beam performed worst with reductions of 16.7% and 56.2% respectively.
This document summarizes a study that analyzes the accuracy of using Darwin guidelines to determine the strength of steel beams with non-compact and slender webs that contain web openings. The study uses finite element analysis in ANSYS to model steel beams with various web opening parameters. It compares the maximum load capacities calculated using Darwin guidelines to those obtained from the finite element analysis. The results show that Darwin guidelines can accurately predict strength for some cases when openings are in high moment or shear zones, but not when in moment-shear combination zones. Therefore, the guidelines may need amendment for use with non-compact and slender beam sections.
The document summarizes a study on the effect of shape of cross-section on the performance of concrete filled steel fluted columns. Twenty-six concrete filled steel fluted columns with different cross-sectional shapes (triangular and rectangular flutes) and L/D ratios were tested. It was found that:
1) Rectangular fluted columns performed better than triangular fluted columns, supporting more load by 1-10%.
2) The moment of inertia was increased by 17-40% for rectangular fluted columns and 9-23% for triangular fluted columns, compared to plain columns.
3) The development length (width) of the fluted columns was 14-34% greater than plain
Experimental Analysis of Mechanical Properties on AA 6060 and 6061 Aluminum A...IJERA Editor
Due to the substantial increased in demands of aluminum in industries like automotive industry and building industry, it is required for improvement of its mechanical properties by addition of suitable alloying elements to aluminum. The objective of this research is to study the effect of various alloys addition to aluminum and their effects on tensile strength, hardness and microstructure. The mechanical properties of AA 6060 and AA 6061 aluminum alloy have been characterized in terms of tensile strength and hardness. The result has been used to determine the tensile strength and % elongation of the specimen. From the results, it has been observed that mechanical properties of Al-alloys increasing up to 0.65% of Mg addition due to grain refinement, where as increase in Mg contents beyond 0.71% mechanical properties starts decreasing. The microstructure of the fracture surface after tensile strength has been examined using inverted microscope.
Experimental investigation on triple blended scc filled steel tubes with and ...eSAT Journals
Abstract
Concrete filled steel tubular columns are gaining its popularity in engineering practice. However, local buckling is the main criteria which effects on strength and ductility for the composite columns. In order to enhance their overall performance, one of the most effective measures is to provide stiffeners for the steel tubes. In the present research, experimental studies have been devoted to investigating the behavior of self-compacting Concrete Filled Steel Tube (CFST) stub columns strengthened by single or double stiffeners. A total of 36 stub columns specimen under monotonic compression load were tested in order to discover the best configuration of column system where (specimen having zero stiffeners, single stiffener, double stiffeners) each for hollow steel and with SCC in-filled are tested for 7 days, 28 days and 56 days strength with circular cross-sections of dimensions 300mm height x100mm diameter x 2mm thickness. The experimental results indicated that the use of Stiffeners strengthen the CFST has a significant effect on the overall behavior of CFST such as enhancement on its strength and ductility. Also the Stiffeners confinement delays local buckling of steel tube, prevents a sudden strength reduction caused by the local buckling of the steel tube, and increases lateral confinement of the concrete core. It is found that the best configuration of Stiffeners in the Steel tubes is providing it in transverse direction with single and double stiffeners at a height of h/2 and h/3 respectively.
The document discusses concrete filled steel tube (CFST) columns under axial compressive loads. It summarizes that CFST columns have higher load capacity than hollow steel tubes due to the composite action between steel and concrete. Experimental tests were conducted on circular and square CFST columns with varying concrete grades and heights. The results showed that square CFST columns had higher load capacity than circular columns. Ultimate load also increased with higher concrete grade. Failure modes included local and overall buckling. CFST columns provide advantages like increased strength, reduced construction costs, and improved fire resistance compared to reinforced concrete columns.
CONCRETE FILLED STEEL TUBULAR COLUMNS USING GS SHEETAL AMIN AZIZ
1) The document presents the findings of an experimental investigation on concrete filled steel tubular columns using galvanized steel sheet strengthened with self-compacting concrete.
2) The investigation found that confined columns exhibited less axial deformation than unconfined columns under the same loads and failed initially at the top and bottom before failing in the middle.
3) It was concluded that confined columns provided higher strength than unconfined columns and failed due to shear stresses, while further research is needed on casting methods and numerical modeling to better understand column behavior.
This short document promotes creating presentations using Haiku Deck, a tool for making slideshows. It encourages the reader to get started making their own Haiku Deck presentation and sharing it on SlideShare. In a single sentence, it pitches the idea of using Haiku Deck to easily create and publish online presentations.
This document is a seminar report submitted by Alok B. Rathod for the degree of Master of Technology in Structural Engineering at Bhartiya Vidya Bhavan’s Sardar Patel College of Engineering in Mumbai, India. The report reviews the development of concrete-filled steel tubular structures, including their material properties and behavior under various loads. It summarizes research on their static, dynamic, and fire performance, as well as construction and durability. Design criteria from different codes are examined and examples of CFST applications in buildings, bridges, and other structures are provided.
This document provides a review of steel-concrete composite (SCC) girders under shock loads. SCC construction combines the advantages of steel and concrete by using mechanical shear connectors to bond a steel beam and concrete slab. Under shock loads, SCC girders can experience local failures like concrete crushing or steel buckling. The complex force transfer during shock loading is discussed. Different types of shear connectors are described, and the interface behavior between the steel beam and concrete slab is important to resist shear forces. Both full and partial composite action are examined in terms of flexural capacity under different interaction assumptions. The behavior of SCC girders under shock loading, including dynamic load factors, is also reviewed.
The document provides an overview of corrosion of steel in concrete. It discusses how steel is usually protected from corrosion by the alkaline environment of concrete but can corrode due to carbonation or chloride attack breaking down the protective layer. The corrosion process involves steel dissolving at the anode and oxygen being consumed at the cathode. This leads to a volume increase and the formation of rust, causing cracking and spalling of concrete. It also describes "black rust" that can occur in low-oxygen conditions without visible damage. The document aims to explain the basics of corrosion mechanisms to help understand investigation and repair techniques.
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.
Energy Absorption Characteristics of Thin Walled Metallic and Foam Filled Tub...IRJET Journal
This document discusses a numerical study comparing the energy absorption characteristics of thin-walled metallic tubular structures with different cross-sectional geometries, both empty and foam-filled. Finite element models of circular, triangular, hexagonal and square tubes undergoing quasi-static axial crushing were created and analyzed. The results show that circular tubes absorbed the most energy of the empty metallic tubes, while foam-filled tubes had higher energy absorption than empty tubes of the same geometry.
Buckling of slender composite concrete filled steel columnsRadhwan Faraj
This document summarizes research analyzing test data on 1817 composite concrete-filled steel columns. The test results are compared to calculations according to Eurocode 4 design methods. Several key findings are presented:
1) Test results for circular composite columns generally corresponded well with Eurocode 4 calculations. Test capacities of rectangular columns agreed with calculations when concrete strength was below 75 MPa.
2) Preloading composite members did not influence load-bearing capacity.
3) Analysis of stress distributions, preloading effects, and stress-strain curves was also examined.
4) Test/calculation ratios from the data indicate Eurocode 4 methods are generally conservative, with average ratios above 1.0 for different column types.
This document summarizes analytical studies on concrete filled steel tubes. A finite element model of a rectangular concrete filled steel tube short column was created using ANSYS software. The model was validated against experimental data. Both eigenvalue and nonlinear buckling analyses were performed to determine the ultimate axial load capacity of the column. The eigenvalue analysis provides the theoretical buckling strength, while the nonlinear analysis is more accurate as it considers factors like imperfections and plastic behavior. The results from the ANSYS model were used to develop an approximate formula for calculating the ultimate load of rectangular concrete filled steel tube short columns based on material properties.
This experimental work aims at presenting load-deflection expressions for the
concrete beams that reinforced with three different reinforcement ratios of ACI 318-
14, which are minimum, maximum and the average of them. Three groups of beams
were cast, each group contained three beam specimens. Three types of loading are
used, 1-concentrated force, 2-concentrated forces and partial uniformly distributed
load. It is also seen that, when reinforcing ratio increases from minimum to
maximum, in case of 1-concentrated force, ultimate capacity increases by about 280%
and deflection decreases by about 33%, respectively. Whereas, in case of 2-
concentrated forces, ultimate capacity increases by about 258% and deflection
decreases by about 50%, respectively. Finally, in case of uniformly distributed load,
ultimate capacity increases by about 289% and deflection decreases by about 28%,
respectively.
This document provides an introduction and literature review on concrete filled steel tube (CFST) columns. Some key points:
1) CFST columns utilize the advantages of both steel and concrete by using a steel hollow section filled with concrete. They are widely used in building construction.
2) Previous research has shown CFST columns have improved structural performance due to confinement of the concrete core by the steel tube. They also have construction advantages due to their simple erection sequence.
3) The literature review covers the behavior of CFST under different load cases like axial, bending, and combined loads. It also discusses design concepts, analytical methods, and codes/standards for CFST columns.
This document provides an overview of concrete filled steel tubes (CFT). It discusses the history and components of CFT, how steel tubes confine concrete and improve its properties. Comparisons are made between CFT and steel or reinforced concrete columns. Applications discussed include tall buildings, bridges and the Canton Tower. Advantages of CFT include increased strength and ductility over steel or concrete alone. Limitations relate to limited knowledge of CFT behavior and determining combined properties.
1) The study tested 4 reinforced self-compacting concrete beams to analyze the effect of construction joints on structural performance.
2) The beams included a reference beam without a joint, and beams with horizontal, vertical at mid-span, and vertical at 1/4 span joints.
3) Test results showed construction joints had a more significant effect on ultimate load than first crack load. The horizontal joint beam performed best with a 6.7% reduction in first crack load and 26.7% reduction in ultimate load compared to the reference beam. The vertical 1/4 span joint beam performed worst with reductions of 16.7% and 56.2% respectively.
This document summarizes a study that analyzes the accuracy of using Darwin guidelines to determine the strength of steel beams with non-compact and slender webs that contain web openings. The study uses finite element analysis in ANSYS to model steel beams with various web opening parameters. It compares the maximum load capacities calculated using Darwin guidelines to those obtained from the finite element analysis. The results show that Darwin guidelines can accurately predict strength for some cases when openings are in high moment or shear zones, but not when in moment-shear combination zones. Therefore, the guidelines may need amendment for use with non-compact and slender beam sections.
The document summarizes a study on the effect of shape of cross-section on the performance of concrete filled steel fluted columns. Twenty-six concrete filled steel fluted columns with different cross-sectional shapes (triangular and rectangular flutes) and L/D ratios were tested. It was found that:
1) Rectangular fluted columns performed better than triangular fluted columns, supporting more load by 1-10%.
2) The moment of inertia was increased by 17-40% for rectangular fluted columns and 9-23% for triangular fluted columns, compared to plain columns.
3) The development length (width) of the fluted columns was 14-34% greater than plain
Experimental Analysis of Mechanical Properties on AA 6060 and 6061 Aluminum A...IJERA Editor
Due to the substantial increased in demands of aluminum in industries like automotive industry and building industry, it is required for improvement of its mechanical properties by addition of suitable alloying elements to aluminum. The objective of this research is to study the effect of various alloys addition to aluminum and their effects on tensile strength, hardness and microstructure. The mechanical properties of AA 6060 and AA 6061 aluminum alloy have been characterized in terms of tensile strength and hardness. The result has been used to determine the tensile strength and % elongation of the specimen. From the results, it has been observed that mechanical properties of Al-alloys increasing up to 0.65% of Mg addition due to grain refinement, where as increase in Mg contents beyond 0.71% mechanical properties starts decreasing. The microstructure of the fracture surface after tensile strength has been examined using inverted microscope.
Experimental investigation on triple blended scc filled steel tubes with and ...eSAT Journals
Abstract
Concrete filled steel tubular columns are gaining its popularity in engineering practice. However, local buckling is the main criteria which effects on strength and ductility for the composite columns. In order to enhance their overall performance, one of the most effective measures is to provide stiffeners for the steel tubes. In the present research, experimental studies have been devoted to investigating the behavior of self-compacting Concrete Filled Steel Tube (CFST) stub columns strengthened by single or double stiffeners. A total of 36 stub columns specimen under monotonic compression load were tested in order to discover the best configuration of column system where (specimen having zero stiffeners, single stiffener, double stiffeners) each for hollow steel and with SCC in-filled are tested for 7 days, 28 days and 56 days strength with circular cross-sections of dimensions 300mm height x100mm diameter x 2mm thickness. The experimental results indicated that the use of Stiffeners strengthen the CFST has a significant effect on the overall behavior of CFST such as enhancement on its strength and ductility. Also the Stiffeners confinement delays local buckling of steel tube, prevents a sudden strength reduction caused by the local buckling of the steel tube, and increases lateral confinement of the concrete core. It is found that the best configuration of Stiffeners in the Steel tubes is providing it in transverse direction with single and double stiffeners at a height of h/2 and h/3 respectively.
The document discusses concrete filled steel tube (CFST) columns under axial compressive loads. It summarizes that CFST columns have higher load capacity than hollow steel tubes due to the composite action between steel and concrete. Experimental tests were conducted on circular and square CFST columns with varying concrete grades and heights. The results showed that square CFST columns had higher load capacity than circular columns. Ultimate load also increased with higher concrete grade. Failure modes included local and overall buckling. CFST columns provide advantages like increased strength, reduced construction costs, and improved fire resistance compared to reinforced concrete columns.
CONCRETE FILLED STEEL TUBULAR COLUMNS USING GS SHEETAL AMIN AZIZ
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- Plunket aims to modernize its services and provide frontline nurses mobile access to digital client information through a new ePHR app.
- Significant challenges include transitioning from paper-based to digital records and ensuring the new system integrates well with clinical workflows.
- Early successes include equipping all frontline nurses with smartphones by 2014. The in-development ePHR app aims to improve access to real-time client data and allow for more time with families.
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IRJET- Numerical Investigation on the Seismic Response of a Steel Girder Brid...IRJET Journal
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Effect of corrosion on concrete reinforcement mechanical and physical 2IAEME Publication
The document summarizes an experimental study on the effect of corrosion on the mechanical and physical properties of steel reinforcement bars in concrete. Three types of steel bars were tested: plain, deformed, and epoxy-coated deformed bars embedded in concrete with varying strengths and water-cement ratios. The bars were subjected to accelerated corrosion testing and evaluated at different corrosion stages. The results showed that corrosion reduces steel bars' tensile strength and ductility. It also decreases yield stress and leads to more brittle failure. Corrosion was found to negatively impact the mechanical properties of reinforcement bars and reduce the load carrying capacity of reinforced concrete structures over time.
IRJET- Analysis of T-Beam Bridge with Mild Steel Strip in various PositionsIRJET Journal
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RELIABILITY STUDIES ON COMPOSITE COLUMNS USING RELIABILITY INDEX APPROACHIRJET Journal
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STRENGTHENING OF PRECAST BEAM-COLUMN JOINT USING STEEL ENCASEMENTIRJET Journal
This document discusses analytical investigations of strengthening precast beam-column joints subjected to monotonic loading using steel encasement. Two strengthening methods are considered: welding steel plates and angles to the joint, and mounting steel plates and angles using prestressed bars. The study aims to improve structural performance metrics like joint strength, ductility, moment capacity, and deflection. Results will be compared to experimental data on cast in situ joints to evaluate the effectiveness of these techniques for precast construction. A beam-column joint is modeled in ANSYS software to analyze the strengthened connections.
Comparative study on Time period and Frequency of Full Arch and Vierendeel T...IRJET Journal
This document presents a comparative study on the time period and frequency of full arch and vierendeel truss steel pedestrian bridges with spans of 40m, 50m, and 60m. Finite element analysis is performed using SAP 2000 software to analyze the bridges under dynamic excitation. The time history analysis is conducted according to IRC codes to determine the natural frequency and time period of different vibration modes. Tables show the calculated time periods and frequencies for the first 12 modes of both bridge types over the three spans. Charts compare the variation of time period and frequency with mode shape. The results show differences in the dynamic response of full arch bridges versus vierendeel truss bridges, and how responses change with increasing span length.
The Study of Flexural and Ultimate Behavior of Ferrocement Lightweight Beam b...IRJET Journal
1. The study examines the flexural and ultimate behavior of ferrocement lightweight beams using autoclaved aerated concrete (AAC) blocks.
2. Six beams were tested - three reinforced concrete beams and three ferrocement beams. Testing involved applying a single point load until failure and recording the first crack load, ultimate load, and deflections.
3. Test results found that ferrocement beams gave early warning of failure through initial cracking compared to sudden failure in reinforced concrete beams. Ferrocement beams also experienced greater deflections than reinforced concrete beams under the same loads.
This document provides information about the Design of Steel Structures course taught by Prof. Durgesh Tupe. It includes the course code, credits, teaching scheme, evaluation scheme, course contents organized in 5 modules, outcomes expected after completion of the course, text books and reference books.
The key concepts covered are types of connections in steel structures, standard rolled sections, types of loads, permissible stresses and factors of safety, methods of design including working stress method, ultimate load method and limit state method. Connections can be riveted, bolted or welded. Loads include dead, live, wind, seismic, snow etc. Methods of design have moved from working stress to limit state for better economy and safety consideration
SUGGESTING DEFLECTION EXPRESSIONS FOR RC 2-WAY SLABSIAEME Publication
The purpose of the experimental work presented in this study is to study the effect
of concrete compressive strength and steel reinforcement ratio on capacity and
deflection of reinforced concrete two-way slabs. Three steel reinforcement ratios are
considered which are minimum, maximum and average of them in addition to two
concrete compressive strength
values of 20 and 30 MPa. The results from
experimental work show that increasing the reinforcing steel ratio leads to increase the
ultimate capacity of the slab in addition to decrease the maximum deflection. For slabs
with
= 20 MPa, increasing the reinforcing steel ratio from the minimum to the
maximum, i.e. 600 %, leads to increase ultimate capacity by about 156 % and decrease
maximum deflection by about 52 %. Wheras, For slabs with
= 30 MPa, increasing
the reinforcing steel ratio from the minimum to the maximum, i.e. 900 %, leads to
increase ultimate capacity by about 155 % and decrease maximum central deflection
by about 27 %. In addition, matmatical expresions for load-deflection relationships are
presented in the current study.
Experimental investigation on effect of shear connector in light weight concreteIAEME Publication
This study experimentally investigates the effect of shear connectors in lightweight concrete composites. Lightweight concrete was produced using quarry dust and glass fibers as partial replacements for normal fine aggregates. Composite beams were produced using cold formed steel sections and lightweight concrete. Different arrangements of stud shear connectors were tested in both normal and lightweight concrete. The results showed that increasing the glass fiber content improved the compressive strength and bond strength between the steel and concrete. The failure modes and strengths of the composite beams were compared. It was found that lightweight concrete composites with higher glass fiber content performed comparably to normal concrete composites.
EXPERIMENTAL INVESTIGATION ON EFFECT OF SHEAR CONNECTOR IN LIGHT WEIGHT CONCRETEIAEME Publication
Composite construction is well established for some decades as a construction method. The light steel gives two advantages which are cheaper and lighter. One of the important parameters which affects the ultimate strength of the composite section is the bond at the interface of the steel
and the concrete which relies on the shear forces existing between the steel section and the concrete core where mechanical connectors are provided. Based on the literature survey, Stud connectors are to be used in this experimental work, because of its excellent load carrying capacity and better
ductility.
This document presents a case study on the long-term effect of different accelerators on the flexural toughness of steel fiber reinforced shotcrete used for tunnel construction. Three types of accelerators - aluminate, cement mineral, and alkali-free - were used to mix shotcrete specimens. The flexural properties of the specimens were evaluated at ages of 1, 3, 6, 12, and 24 months according to Japanese and American standards. The results showed that alkali-free accelerators provided better long-term performance in terms of strength and toughness while also improving worker safety and environmental protection. Based on the long-term effectiveness, alkali-free accelerators were proposed as the best choice for tunnel construction applications.
IRJET- Dynamic Analysis of Tall Tubular Steel Structures for Different Geomet...IRJET Journal
This document analyzes the dynamic behavior of tall tubular steel structures with different geometric configurations (square, rectangular, triangular, hexagonal) using computer modeling and simulation. Modal analysis showed hexagonal structures have the longest period and lowest frequency, indicating greater stability. Earthquake and wind analyses found hexagonal structures experienced the highest displacements and drift. In general, tubular structures performed better than conventional steel frames. Future work could optimize hexagonal designs using additional structural systems or analyze complex tube-in-tube configurations.
IRJET - An Experimental Study of Flexural Behaviour and Corrosion Propert...IRJET Journal
This document summarizes an experimental study on the flexural behavior and corrosion properties of reinforced concrete beams. The study aimed to induce corrosion on steel bars with and without corrosion resistant coating in beams, and determine the impact on residual flexural capacity. Beams were tested after 7 and 28 days to analyze load-carrying capacity and deflection. Results showed corrosion resistant beams had higher strength and intermediate deflection compared to conventional and corroded beams. The study concluded the corrosion resistant coating provided effective and affordable protection to rebar compared to uncoated bars, improving beam performance over time.
Stiffening and Strengthening of Deteriorated Cellular Beams by Local Post- Te...IRJET Journal
This document discusses research on strengthening deteriorated cellular beams through local post-tensioning. Cellular beams are prone to deterioration over time due to their increased depth and exposure. The study aims to introduce local post-tensioning as a simple, low-cost method to stiffen and strengthen cellular beams without adding new material. Local post-tensioning involves attaching reinforcing bars to the bottom of the beam and tensioning them using jacks to improve load capacity. Deteriorated beams were modeled and analyzed in ANSYS. The results showed that local post-tensioning combined with stiffeners was the most effective approach, able to recover over 180% of the original load capacity.
Study on Steel Beam Column Joint using Different Connections – State of ArtIRJET Journal
This document summarizes research on different types of steel beam-column connections, focusing on reduced beam section (RBS) connections. It discusses how RBS connections improve ductility by localizing plastic hinging in the reduced beam section, away from the connection. Several studies are summarized that experimentally and numerically analyze the behavior of RBS connections under cyclic loading, finding they provide excellent ductile performance by maintaining the elasticity of the connection region. Parameters like RBS geometry and profile are investigated. The document concludes RBS connections enhance seismic performance by preventing failure of connection components.
IJET-Waste Water Treatment Unit using Activated CharcoalIRJET Journal
This document summarizes research on different types of steel beam-column connections, focusing on reduced beam section (RBS) connections. It discusses how RBS connections improve ductility by localizing plastic hinging in the reduced beam section, away from the connection. Several studies are summarized that evaluate the behavior and performance of RBS connections through experimental testing and finite element modeling. The research shows that RBS connections can provide excellent seismic performance by maintaining the elastic behavior of the connection while forming plastic hinges in the reduced beam section.
Numerical Study of Wire Mesh Orientation on Retrofitted RC Beams using Ferroc...IRJET Journal
This document presents the results of a numerical study using finite element analysis to investigate the behavior of reinforced concrete beams retrofitted with ferrocement jackets containing different wire mesh orientations. Four beams were modeled and analyzed: a control beam without retrofitting and beams retrofitted with 0°, 45°, and 60° wire mesh orientations. The analysis found that the beam with a 45° wire mesh orientation exhibited the highest load carrying capacity and lowest deflection compared to the other beams. All of the retrofitted beams also showed an increase in ductility ratio compared to the control beam.
An Analytical and Experimental Investigation of Shear Connectors in Composite...IRJET Journal
This document analyzes and compares the structural behavior of different types of shear connectors in composite beams through analytical and experimental methods. Finite element analysis was conducted using ANSYS to model composite beams with channel, stud, and bolt shear connectors. Standard push-out tests were also performed on composite sections with various connectors. The analytical and experimental results showed that channel shear connectors had the highest load carrying capacity and ductility compared to stud and bolt connectors. Failure modes also differed between connector types.
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Reduction of Ultimate Strength due to Corrosion - A Finite Element Computational Method
1. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 194
Reduction of Ultimate Strength due to Corrosion - A Finite
Element Computational Method
J.M. Ruwan S. Appuhamy ruwan@cee.ehime-u.ac.jp
Department of Civil and Environmental Engineering,
Ehime University, Bunkyo-cho 3,
Matsuyama 790-8577, Japan.
Mitao Ohga ohga@cee.ehime-u.ac.jp
Department of Civil and Environmental Engineering,
Ehime University, Bunkyo-cho 3,
Matsuyama 790-8577, Japan.
Tatsumasa Kaita kaita@tokuyama.ac.jp
Department of Civil Engineering & Architecture,
Tokuyama College of Technology,
Shunan 745-8585, Japan.
Ranjith Dissanayake ranjith@civil.pdn.ac.lk
Department of Civil Engineering,
University of Peradeniya, Peradeniya,
20400, Sri Lanka.
Abstract
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.
Keywords: Bridges, Corrosion, Maximum Corroded Depth, FEM Analysis, Remaining Strength.
1. INTRODUCTION
Corrosion of the members of a steel structure leads to impairment of its operation and
progressive weakening of that structure. The consequences of corrosion are many and varied
and effects of these on safe, reliable and efficient operation of structures are often considered
than simply loosing of a volume of metal. Various kinds of failures and the need of expensive
replacements may occur even though the amount of metal destroyed is quite small. One of the
major harmful effects of corrosion is the reduction of metal thickness leading to loss of
mechanical strength and structural failure, causing severe disastrous and hazardous injuries to
the people. Therefore, understanding of the influence of damage due to corrosion on the
remaining load-carrying capacities is a vital task for the maintenance management of steel
highway and railway infrastructures.
2. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 195
Though it’s a maintenance issue, it can be addressed appropriately by specification of a proper
corrosion system in the design phase. It has been proved that the corrosion played a significant
role in the catastrophic collapse of both the Silver Bridge (Point Pleasant, WV) in 1967 and the
Mianus River Bridge (Connecticut) in 1983, USA [1]. Those collapses indicated the paramount
importance of attention to the condition of older bridges, leading to intensified inspection protocols
and numerous eventual retrofits or replacements [2,3]. Therefore corrosion is not an issue to be
taken lightly either in design phase or in maintenance stage. Detailed regular inspections are
necessary in order to assure adequate safety and determine maintenance requirements, in bridge
infrastructure management. But the number of steel bridge infrastructures in the world is steadily
increasing as a result of building new steel structures and extending the life of older structures.
So, there is a need of more brisk and accurate assessment method which can be used to make
reliable decisions affecting the cost and safety.
During the past few decades, several experimental studies and detailed investigations of
corroded surfaces were done by some researchers in order to introduce methods of estimating
the remaining strength capacities of corroded steel plates [4-7]. But, to develop a more reliable
strength estimation technique, only experimental approach is not enough as actual corroded
surfaces are different from each other. Further, due to economic constraints, it is not possible to
conduct tests for each and every aged bridge structure within their bridge budgets. Therefore,
bridge engineers are faced with lack of experimental and field data. Therefore, nowadays, use of
numerical analysis method could be considered to have a reliable estimation in bridge
maintenance industry [8].
Sidharth et al. [9] stated the importance and reviewed the abreast development in the FE analysis
technique used to study the corrosion effect on the plates. Ahmmad et al. [10] investigated the
deformability of corroded steel plates under quasi-static uniaxial tension through both
experimental and numerical analyses. They proposed empirical formulae to estimate the
reduction in deformability and energy absorption capacity due to pitting corrosion and general
corrosion under uniaxial tension. Therefore it can be seen that the finite element analysis method
has now become the most common, powerful and flexible tool in rational structural analysis and
makes it possible to predict the strength of complex structures more accurately than existing
classical theoretical methods.
Even though, it is an exigent task to conduct detail investigations of all existing steel structures as
the number of steel structures are steadily increasing in the world, it is necessary to assess those
structures in regular basis to ensure their safety and determine the necessary maintenance.
Therefore, developing a rapid and accurate methodology to estimate the remaining strength
capacities of steel infrastructures is a vital task in maintenance engineering. Therefore, this paper
proposes a simple, accurate and brisk analytical method which can be used to make reliable
decisions on the maintenance management of existing steel infrastructures.
2. CORRODED TEST SPECIMENS
The test specimens were cut out from a steel girder of Ananai River in Kochi Prefecture on the
shoreline of the Pacific Ocean, which had been used for about hundred years. This bridge had
simply supported steel plate girders with six spans, with each of 13.5 m. All plate girders were
constructed by rivet joints and were exposed to high airborne salt environment by strong sea wind
for a long time. It was constructed as a railway bridge in 1900, and in 1975 changed to a
pedestrian bridge, when the reinforced concrete slab was cast on main girders. The bridge was
dismantled due to serious corrosion damage in year 2001. Many severe corrosion damages
distributed all over the girder, especially, large corrosion pits or locally-corroded portions were
observed on upper flanges and its cover plates. Then, 21 (F1-F21) and 5 (W1-W5) test
specimens were cut out from the cover plate on upper flange and web plate respectively.
Before conducting the thickness measurements, all rusts over both surfaces were removed
carefully by using the electric wire brushes and punches. Then, two new SM490A plates
3. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 196
(t=16mm) were jointed to both sides of specimen by the butt full penetration welding for grip parts
to loading machine, as shown in Figure 1. Here, the flange and web specimens have the widths
ranged from 70-80 mm and 170-180 mm respectively. The test specimen configuration is shown
in Figure 1. In addition, 4 corrosion-free specimens (JIS5 type) were made of each two from
flange and web, and the tensile tests were carried out in order to clarify the material properties of
test specimens. The material properties obtained from these tests are shown in Table 1.
170-180mm
300mm 380-400mm 300mm
SM490A
Corroded Test Specimen
SM490A
Welding
Corroded Test Specimen
Welding
SM490A
300mm200-250mm300mm
70-80mm SM490A
FIGURE 1: Dimensions of test specimens.
TABLE 1: Material properties
Accuracy, convenience, portability and lightness are highly demanded for choosing of a device for
the on-site measurement of corroded surface irregularities. Therefore, the portable 3-dimentional
scanning system, which can measure the 3-dimentional coordinate values at any arbitrary point
on the corrosion surface directly and continuously, was used for the measurement of surface
irregularities of the test specimens [11]. Here, the thickness of the corroded surface can be
calculated easily from those measured coordinates. The measuring device has three arms and
six rotational joints, and can measure the coordinates of a point on steel surface by using the
non-contact scanning probe (laser line probe). The condition of thickness measurement is shown
in Figure 2. Since this probe irradiates the steel surface with a laser beam, which has about
100mm width, the large number of 3-dimensional coordinate data can be obtained easily at a
time. So, the thicknesses of all scratched specimens were measured by using this 3D laser
scanning device and the coordinate data was obtained in a grid of 0.5mm intervals in both X and
Y directions. Then, the remaining thicknesses of all grid points were calculated by using the
difference of the coordinate values of both sides of those corroded specimens. Then, the
statistical thickness parameters such as average thickness (tavg), minimum thickness (tmin),
standard deviation of thickness (σst) and coefficient of variability (CV) were calculated from the
measurement results.
Specimen
Elastic
modulus
/(GPa)
Poisson’s
ratio
Yield
stress
/(MPa)
Tensile
strength
/(MPa)
Elongation
at breaking
/(%)
Corrosion-free plate (flange) 187.8 0.271 281.6 431.3 40.19
Corrosion-free plate (web) 195.4 0.281 307.8 463.5 32.87
SS400 JIS 200.0 0.300 245~ 400~510 –
4. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 197
FIGURE 2: Condition of thickness measurement.
Even though, various types of corrosion conditions in actual steel structures can be seen as the
corrosion damage can take place in many shapes and forms, it is necessary to categorize those
different corrosion conditions to few general types for better understanding of their remaining
strength capacities. So, in this study, all specimens were categorized into 3 typical corrosion
types concerning their visual distinctiveness, amount of corrosion, expected mechanical and
ultimate behaviors and minimum thickness ratio, µ (minimum thickness/ initial thickness) [7].
Here, the 3 different types of corrosion levels can be classified according to their severity of
corrosion as follows:
µ > 0.75 ; Minor Corrosion
0.75 ≥ µ ≥ 0.5 ; Moderate Corrosion
µ < 0.5 ; Severe Corrosion
Three specimens F-14, F-13 and F-19 with minor, moderate and severe corrosion conditions
respectively are shown in Figure 3.
FIGURE 3: Plates with (a) minor [F-14], (b) moderate [F-13] and (c) severe [F-19] corrosion.
3. EXPERIMENTAL ANALYSIS AND RESULTS
Tensile loading tests were carried out at constant velocity under loading control by using a
hydraulic loading test machine (maximum load: 2940KN) for all 26 specimens with different
corrosion conditions. The loading velocity was set to 200N/sec for minor corroded specimens and
150N/sec for moderate and severe corroded specimens.
Figure 4 shows the load-elongation curves for three different corroded specimens with 3
corrosion types. The specimens F-14 and F-13 have comparatively larger minimum thickness
ratio (µ = 0.783 and 0.512 respectively) and the specimen F-19 in which the corrosion
progression was more severe, the minimum thickness ratio is also diminutive (µ = 0.061). Herein,
the specimen (F-14) with minor corrosion has almost same mechanical properties (such as
apparent yield strength and load-elongation behavior etc.) as the corrosion-free specimen. On the
other hand, the moderate corroded specimen (F-13) and the severe corroded specimen (F-19)
show obscure yield strength and the elongation of the specimen F-19 decreases notably. The
(a) (b) (c)
5. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 198
reason for this is believed to be that the local section with a small cross-sectional area yields at
an early load stage because of the stress concentration due to irregularity of corroded steel plate.
And this will lead moderate and severe corroded members elongate locally and reach to the
breaking point.
Displacement (mm)
Load(kN)
F-14 (Minor corrosion)
F-13 (Moderate corrosion)
F-19 (Severe corrosion)
0 10 20 30 40 50
50
100
150
200
250
300
350
FIGURE 4: Load-displacement curves.
Even though the relation between the breaking section and the thickness distribution is not
exactly clarified yet, it can be seen that most of minor corrosion members are failed in a section
corresponds to a minimum thickness point (tmin) or a minimum average thickness point (tsa) for the
members with the thickness variation is very small. Also, it was noted that the breaking point of
moderate and severe corrosion members are corresponds to a section of the minimum thickness
point. Therefore, the local statistical parameters with the influence of stress concentration can be
used for the yield and tensile strength estimations.
4. NUMERICAL INVESTIGATION
4.1 Analytical Model
The 3D isoparametric hexahedral solid element with eight nodal points (HX8M) and updated
Lagrangian method based on incremental theory were adopted in these analyses. Non linear
elastic-plastic material, Newton-Raphson flow rule and Von Mises yield criterion were assumed
for material properties. Further, an automatic incremental-iterative solution procedure was
performed until they reached to the pre-defined termination limit.
FIGURE 5: Analytical model of corroded member.
6. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 199
The analytical models with different length (L) and width (W) dimensions were modeled with their
respective corrosion conditions as shown in Figure 5. One edge of the member’s translation in X,
Y and Z directions were fixed and only the Y and Z direction translations of the other edge
(loading edge) were fixed to simulate with the actual experimental condition. Then the uniform
incremental displacements were applied to the loading edge. Yield stress σy = 294.7 [MPa],
Elastic modulus E = 191.6 [GPa], Poisson’s ratio ν = 0.276 were applied to all analytical models,
respectively.
4.2 Ductile Fracture Criterion
Fracture is an important mode of failure in steel structures, and accurate assessment of fracture
is necessary to understand the ultimate behaviors. The “Stress Modified Critical Strain Model
(SMCS)” was proposed by Kavinde et al. (2006), to evaluate the initiation of ductile fracture as a
function of multiaxial plastic strains and stresses [12]. This method was adopted in this analytical
study. In SMCS criterion, the critical plastic strain ( Critical
Pε ) is determined by the following
expression:
−⋅=
e
mCritical
P
σ
σ
5.1Expαε (1)
Where, α is toughness index and the stress traxiality T = (σm/σe), a ratio of the mean or hydrostatic
stress (σm) and the effective or von Mises stress (σe). The toughness index α is a fundamental
material property and hence obtained from the tensile test conducted for the non corroded
specimen and obtained as follows:
−
=
e
m
Critical
P
σ
σ
5.1Exp
ε
α
(2)
The ultimate strength of each corroded specimen was calculated accordingly by using the SMCS
criterion and compared with their experimental ultimate capacities to understand the feasibility of
the numerical modeling approach for remaining strength estimation of corroded steel plates with
different corrosion conditions.
4.3 Analytical Results and Discussion
The yield and ultimate strengths in analytical prediction were estimated and compared with that of
the experimentally obtained values to evaluate the accuracy of the used analytical model. The
percentage error in yield and tensile strength in analytical predictions are calculated as:
100
P
P-P
=PinError%
ntal]y[Experime
ntal]y[Experimeal]y[Analytic
y • (3)
100
P
P-P
=PinError%
ntal]b[Experime
ntal]b[Experimeal]b[Analytic
b • (4)
First, analytical modeling of the non-corroded specimen was done with above described modeling
and analytical features to understand the accuracy of the adopted procedure. It was found that
the analytical model results were almost same as the experimental results with having a
negligible percentage error of 0.03% and 0.02% in yield and tensile strengths respectively. Then,
all other experimentally successful specimens were modeled accordingly and their yield and
ultimate strengths were compared with the experimentally obtained values.
(a) Minor Corrosion Members
The above described analytical procedure was used to model the members with minor corrosion
to understand their yield and ultimate behaviors and to obtain their failure surfaces. Comparison
of experimental and analytical load-displacement curves of specimen F-14 is shown in Figure 6.
Here, the percentage errors in yield and tensile strength predictions of member F-14 are 0.53%
7. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 200
and 0.03% respectively. So, it is revealed that this numerical modeling technique can be used to
predict the remaining strength capacities of minor corroded members accurately.
The failure surface was obtained from the most narrowed location of the deformed shape of the
analytical model. Figure 7 shows that both experimental and analytical failure surfaces of the
specimen F-14 are in good agreement.
Displacement, (mm)
Load(kN)
F-19 (Severe)-Experimental
F-19 (Severe)-Numerical
Numerical Fracture Point
Experimental Ultimate Load
0 10 20 30 40 50
50
100
150
200
250
300
350
FIGURE 6: Comparison of load-displacement curves of minor corrosion member [F-14].
FIGURE 7: Stress distribution at ultimate load of minor corrosion member [F-14].
(b) Moderate Corrosion Members
Then, the members with moderate corrosion were also analyzed and compared with their
respective experimental results. The Figure 8 shows the comparison of load-displacement
behavior of moderately corroded member, F-13. It shows a very good comparison of experimental
and analytical load-displacement behaviors in members with moderate corrosion as well and the
percentage errors in yield and tensile strength predictions of member F-13 are 2.96% and 0.70%
respectively.
Further, the Figure 9 shows that a similar failure surface could be obtained as in experimental
analysis and this indicate the adaptability of this analytical modeling method and SMCS fracture
criterion for moderately corroded members too, in order to predict their remaining strength
capacities.
8. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 201
Displacement, (mm)
Load(kN) F-19 (Severe)-Experimental
F-19 (Severe)-Numerical
Numerical Fracture Point
Experimental Ultimate Load
0 5 10 15 20 25
50
100
150
200
250
300
FIGURE 8: Comparison of load-displacement curves of moderate corrosion member [F-13].
FIGURE 9: Stress distribution at ultimate load of moderate corrosion member [F-13].
(c) Severe Corrosion Members
Finally, the severely corroded members too analyzed and observed their yield and ultimate
behaviors and their failure surfaces. The Figure 10 shows the comparison of load-displacement
behavior of severely corroded specimen F-19. It shows that an adequate comparison of
experimental and analytical load-displacement behaviors can be obtained in members with
severe corrosion as well.
The percentage errors in yield and tensile strength predictions of member F-19 shown in Figure
10 are 3.20% and 5.53% respectively. Though the ultimate behavior shows a slight difference,
the failure surface shown in Figure 11 is almost same as in the experimental analysis.
Although the results of numerical predictions for yield and ultimate strengths of minor and
moderate corroded members show a very good comparison with the experimental results, severe
corrosion members show a little bit deviation in their ultimate strength predictions. The reason
could be that, some microscopic cracks could also build-up with the development of corrosion
which they could eventually results a loss of strength. Hence, there we can see a loss of tensile
strength in experimental analyses than expected or predicted by analytical models in severely
corroded specimens. So, careful microscopic observations for severe corroded surfaces and
smoothing them neatly could reduce such errors with analytical prediction.
9. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 202
Displacement, (mm)
Load(kN)
F-19 (Severe)-Experimental
F-19 (Severe)-Numerical
Numerical Fracture Point
Experimental Ultimate Load
0 2 4 6 8 10
50
100
150
200
250
FIGURE 10: Comparison of load-displacement curves of severe corrosion member [F-19].
FIGURE 11: Stress distribution at ultimate load of severe corrosion member [F-19].
(d) Discussion
All experimentally successful flange and web specimens were modeled accordingly and their yield
and ultimate strengths and failure surfaces were compared with the experimental behaviors. A
good comparison of the experimental and analytical load-elongation behaviors for all three
classified corrosion types was obtained. Figure 12 shows the comparison of ultimate load
capacities of experimental and numerical analyses with 2mm models. Having a coefficient of
correlation of R2
= 0.994 indicates the accuracy and the possibility of numerical investigation
method to predict the tensile strength of actual corroded specimens.
Failure surfaces obtained from the analytical method and the experimental analysis indicated a
very good comparison for all three corrosion categories and hence this fact too signifies the
accuracy of the adopted numerical modeling method. Further, it can be seen that the elongation
of members with minor corrosion have comparatively same elongation as corrosion free members,
where as the moderately corroded members show lesser elongation than the minor corrosion
members. Also the members with severe corrosion show significant reduction in elongation as
well. The reason for this could be the local section with a small cross-sectional area yields at an
early load stage because of the stress concentration due to irregularity of corroded steel plate
which elongates locally and reach to the breaking point.
10. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 203
Experimental Pb (kN)
NumericalyPredicted(2mmdata)Pb(kN)
Coefficient of Correlation: R2
= 0.994
100 150 200 250 300 350
100
150
200
250
300
350
FIGURE 12: Comparison of experimental and analytical ultimate load capacities.
5. DEVELOPMENT OF BRISK ANALYTICAL METHOD
5.1 Corrosion Condition Modeling (CCM) Parameters
Since it is an exigent task to conduct detail corroded surface measurements for all aged steel
infrastructures as the number of steel structures are steadily increasing in the world, a simple,
accurate and brisk method is deemed necessary to model different corroded surfaces numerically
and predict their yield and ultimate behaviors. Therefore two parameters were defined to model
the corroded surface considering the stress concentration effect and to obtain the yield and
ultimate behaviors more accurately. The following Figure 13(a) shows the variation of diameter of
the maximum corroded pit vs. maximum corroded depth (tc,max) and Figure 13(b) shows the
normalized average thickness (tavg/t0) vs. normalized maximum corroded depth (tc,max/t0). Both
Figures show a very good linear relationship and hence these parameters were used to develop
an analytical model which can be used to predict the yield and ultimate behaviors of corroded
steel plates with different corrosion conditions.
Maximum corroded depth, tc,max (mm)
Diameterofcorrodedpit,D(mm)
Y = 5.2 X
R2
= 0.963
0 2 4 6 8 10
10
20
30
40
50
60
Nomalized maximum corroded depth (tc,max/t0)
Nomalizedaveragethickness(tavg/t0)
Y = 1 - 0.196 X
R2
= 0.799
0 0.2 0.4 0.6 0.8 1
0.2
0.4
0.6
0.8
1.0
1.2
FIGURE 13: Relationship of (a) D vs. tc,max and (b) normalized tavg vs. tc,max.
(a) (b)
11. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 204
Therefore, by considering the Figures 13(a) and (b), the two equations for the corrosion condition
modeling (CCM) parameters can be defined as:
D* = 5.2 tc,max (5)
t*avg = t0 - 0.2 tc,max (6)
where D* and t*avg are the representative diameter of maximum corroded pit and representative
average thickness respectively.
5.2 Analytical Model
An analytical model is developed with the above CCM parameters for each corroded specimen
with different corrosion conditions as shown in Figure 14. Here, the maximum corroded pit was
modeled by using the representative diameter (D*) which could account the stress concentration
effect and the material loss due to corrosion was considered by using the representative average
thickness parameter (t*avg). The same modeling features and analytical procedure as described in
section 4 were adopted for the analyses. Then the results of this model were compared with the
experimental results to understand the effectiveness of the proposed model.
*
*
D
D
*
avgt
*
avgt
mint
t0
tmin
SectionalView
mint0t
Sectional View
Plan View
W
L
FIGURE 14: Analytical model with CCM parameters.
5.3 Analytical Results and Discussion
The load-elongation behavior of 3 members F-14, F-13 and F-19 with minor, moderate and
severe corrosion conditions respectively are shown in Figure 15 bellow. It was revealed that a
very good comparison of the load-elongation behavior can be seen for the all three classified
corrosion types. Here, the percentage errors in yield and tensile strength predictions of the
proposed analytical model for the three corrosion types are 0.13% and 0.83% in F-14, 0.38% and
1.01% in F-13 and 3.51% and 2.69% in F-19 respectively. Further it was noted that there is no
significance in % errors even though they tend to increase with the severity of corrosion.
Then, all experimentally successful specimens were modeled accordingly with the proposed
analytical model and their yield and ultimate strengths and failure surfaces were compared with
the experimental results. The Figure 16 shows the comparison of ultimate load capacities of
proposed model and experimental results. A very good comparison with a coefficient of
correlation of R2
= 0.992 was attained. This fact divulges the accuracy of the proposed model and
the possibility of the use of proposed analytical model instead of the model with detailed corroded
surface measurements. Therefore it can be comprehended that the adopted method and the
proposed analytical model can be used to predict the yield and ultimate behaviors precisely.
Further it was noticed that a good agreement of the failure surfaces of experimental and
proposed model can be obtained too.
12. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 205
Displacement, (mm)
Load(kN)
Numerical Fracture Points
F-14 (Minor)-Experimental
F-14 (Minor)-Numerical
F-13 (Moderate)-Experimental
F-13 (Moderate)-Numerical
F-19 (Severe)-Experimental
F-19 (Severe)-Numerical
0 10 20 30 40 50
50
100
150
200
250
300
350
FIGURE 15: Comparison of load-elongation curves of proposed analytical model.
Experimental Pb (kN)
NumericalyPredicted(ProposedModel)Pb(kN)
Coefficient of Correlation: R2
= 0.992
100 150 200 250 300 350
100
150
200
250
300
350
FIGURE 16: Comparison of experimental and proposed model’s ultimate load capacities.
Further, it was noted that the available numerical methods and empirical equations developed by
various authors require conducting detail corroded surface measurements and the measurement
of average thickness and/or the minimum average thickness, in order to develop the analytical
model and predict the yield and ultimate behaviors of that corroded members. But, the proposed
model require only the measurement of maximum corroded depth (tc,max), which can be easily
identified through a careful visual inspection of the corroded surface, in order to develop the
analytical model considering the stress concentration effect and the material loss due to corrosion.
Therefore, this method can be used as a simple, reliable and brisk analytical method for the
maintenance management of steel infrastructures.
A further detailed study comprises with experimental and numerical analysis of more specimens
with different corrosion conditions is deemed necessary to understand the significance of the
proposed method and verify this for different corroded levels and environmental conditions.
13. J.M. Ruwan S. Appuhamy, Mitao Ohga, Tatsumasa Kaita & Ranjith Dissanayake
International Journal of Engineering (IJE), Volume (5) : Issue (2) : 2011 206
6. CONCLUSIONS
The 26 specimens taken out of the scrapped plate girder which had been used for about 100
years with severe corrosion, was used to perform the tensile tests to estimate the mechanical
properties of corroded plates and understand the relationship of strength reduction and their level
of corrosion. A non-linear FEM analysis was carried out to understand the mechanical behavior,
stress distribution, ultimate behavior etc. for members with different corroded conditions. The main
conclusions are as follows:
1. The corrosion causes strength reduction of steel plates and minimum thickness ratio (µ) can
be used as a measure of the level of corrosion and their strength degradation.
2. A very good agreement between the experimental and non linear FEM results can be seen
for all three classified corrosion types. Further, failure surfaces of those specimens too
showed a very good comparison with the experimental results. So, the adopted numerical
modeling technique can be used to predict the remaining strength capacities of actual
corroded members accurately.
3. Proposed analytical model with CCM parameters showed a very good agreement with the
experimental results for all three classified corrosion types. Further, the proposed method is
simple and gives more accurate remaining strength estimation of corroded steel plates.
Therefore this analytical model, developed by the measurement of maximum corroded depth
only, can be used as a reliable and brisk method for the maintenance management of
corroded steel infrastructures.
7. ACKNOWLEDGEMENTS
The authors would like to thank the technical staffs of Mitutoyo Corporation (Japan) for their
assistance in surface measurement of corroded specimens and Mr. Y. Tanabe, Mr. H. Ikeda and
Mr. K. Itogawa for their support extended during the experimental work.
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