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Papers by Ebrahim Farajpourbonab
Asian Journal of Civil Engineering, 2018
A numerical study has been done on the strength and hysteresis behavior of castellated and common... more A numerical study has been done on the strength and hysteresis behavior of castellated and common cruciform steel columns under axial and lateral cyclic loading. The main feature of the castellation method is to make the I-sections stiffer by increasing the web height and reaching the higher moment capacity from the initial axis of the same weight of plain webbed members, and optimizing the use of heavy and costly constructional steel material and providing access to appropriate services. The effect of types of steel sections, web and flange boost of steel section, and length variations of specimens have been investigated and deformation, bearing capacity, hysteresis loops, ductility, and energy dissipation capacities have been discussed. Finite element analysis is performed based on initial geometric imperfection and geometric nonlinearity. The results of finite element analyses are close to the experimental results and showed that load carrying capacity of castellated cruciform st...
The steel tubular column filled with steel reinforced concrete (SRCFT), is formed by inserting a ... more The steel tubular column filled with steel reinforced concrete (SRCFT), is formed by inserting a steel section into a concrete filled steel tube. In the current paper, a new shape, namely Castellated Cruciform Steel Section (CCSS), for reinforcing of CFT columns has been proposed to improve the compressive strength and hysteresis behavior of these columns under moderate and severe earthquake excitations. A comprehensive study has been conducted to investigate the strength of SRCFT columns reinforced with castellated and traditional cruciform steel sections, made with thin-walled, welded I-section. The paper describes and presents the results of the testing of four small size (155 mm*155 mm) and short column specimens. The experimental results indicate that the new steel section causes high strength and better post yield behavior of SRCFT columns, because of the increase of shear and bending strength, torsion resistance and interaction between the hollow steel section and concrete. I...
Journal of Structural Fire Engineering
Purpose The primary purpose of this research was to expand the knowledge base regarding the behav... more Purpose The primary purpose of this research was to expand the knowledge base regarding the behavior of steel columns during exposure to fire. This paper presents the numerical study of the effect of heat on the performance of parking steel column in a seven-story steel building under cyclic loading. Design/methodology/approach In this research, the forces and deformations developed during a fire are estimated by using detailed 3D finite-element models. The analyses are in the form of a coupled thermo-mechanical analysis in two types of loading: concurrent loading (fire and cyclic loading) and non-concurrent loading (first fire and then cyclically), and the analyses have been conducted in both states of the fire loading with cooling and without cooling using the ABAQUS software. Further, it was investigated whether, during the fire loading, the specimen was protected by a 3-cm-thick concrete coating and how much it changes the seismic performance. After verification of the specimen with the experimental test results, the column model was investigated under different loading conditions. Findings The result of analyses indicates that the effect of thermal damage on the performance of steel columns, when cooling is happening late, is more than the state in which cooling occurs immediately after the fire. In this paper, thermal–seismic performance of parking steel columns has been specified and the effect of the fire damage has been investigated for the protected steel by concrete coating and to the non-protected steel, under both cooling and non-cooling states. Originality/value This study led to recommendations based on the findings and suggestions for additional work to support performance-based fire engineering. It is clear that predicting force and deformation on steel column during fire is complex and it is affected by many variables. Here in this paper, those variables are examined and proper results have been achieved.
Journal of Urban and Environmental Engineering
Based on some findings on the two kinds of Concrete Filled Double Skin steel Tube (CFDST) members... more Based on some findings on the two kinds of Concrete Filled Double Skin steel Tube (CFDST) members with circular or square sections, a new kind of CFDST with octagonal and polygonal section have been investigated under axial and cyclic loading. For this purpose, the outer steel wall has various steel shapes and the inner steel wall is the same as circular section and for some part of analyses, the outer tube is the same as circular section and the inner wall has various steel sections. Primarily, FEM procedure has been verified with some available experimental studies and then, seven composite columns with different section types have been analyzed. The results of analyses exhibited the increase in strength and improvement in hysteresis behavior of the proposed steel sections under cyclic loading.
Istrazivanja i projektovanja za privredu
Concrete Filled Double Skin Steel Tubular (CFDST) columns could be considered as a new type of co... more Concrete Filled Double Skin Steel Tubular (CFDST) columns could be considered as a new type of concrete filled steel tubular (CFT) columns. These columns are composed of two steel tubes in the concentric configurations with concrete between them. In the current study, finite element method was used to analyze the effects of load application, type of material, and geometric parameters of the specimens. It was found that the results obtained from finite element analysis show good agreement with available experimental results. Findings of the current study clearly indicate the high ductility and strength of CFDST columns under axial loading. The results show the significant impact of yield stress of steel section, compressive strength of concrete, thickness and diameter variations on the strength and ductility of CFDST columns.
International Journal of Advanced Structural Engineering
SRCFT columns are formed by inserting a steel section into a concrete-filled steel tube. These ty... more SRCFT columns are formed by inserting a steel section into a concrete-filled steel tube. These types of columns are named steel-reinforced concrete-filled steel tubular (SRCFT) columns. The current study aims at investigating the various types of reinforcing steel section to improve the strength and hysteresis behavior of SRCFT columns under axial and lateral cyclic loading. To attain this objective, a numerical study has been conducted on a series of composite columns. First, FEM procedure has been verified by the use of available experimental studies. Next, eight composite columns having different types of cross sections were analyzed. For comparison purpose, the base model was a CFT column used as a benchmark specimen. Nevertheless, the other specimens were SRCFT types. The results indicate that reinforcement of a CFT column through this method leads to enhancement in load-carrying capacity, enhancement in lateral drift ratio, ductility, preventing of local buckling in steel shell, and enhancement in energy absorption capacity. Under cyclic displacement history, it was observed that the use of cross-shaped reinforcing steel section causes a higher level of energy dissipation and the moment of inertia of the reinforcing steel sections was found to be the most significant parameter affecting the hysteresis behavior of SRCFT columns.
World Journal of Engineering
Asian Journal of Civil Engineering, 2018
A numerical study has been done on the strength and hysteresis behavior of castellated and common... more A numerical study has been done on the strength and hysteresis behavior of castellated and common cruciform steel columns under axial and lateral cyclic loading. The main feature of the castellation method is to make the I-sections stiffer by increasing the web height and reaching the higher moment capacity from the initial axis of the same weight of plain webbed members, and optimizing the use of heavy and costly constructional steel material and providing access to appropriate services. The effect of types of steel sections, web and flange boost of steel section, and length variations of specimens have been investigated and deformation, bearing capacity, hysteresis loops, ductility, and energy dissipation capacities have been discussed. Finite element analysis is performed based on initial geometric imperfection and geometric nonlinearity. The results of finite element analyses are close to the experimental results and showed that load carrying capacity of castellated cruciform st...
The steel tubular column filled with steel reinforced concrete (SRCFT), is formed by inserting a ... more The steel tubular column filled with steel reinforced concrete (SRCFT), is formed by inserting a steel section into a concrete filled steel tube. In the current paper, a new shape, namely Castellated Cruciform Steel Section (CCSS), for reinforcing of CFT columns has been proposed to improve the compressive strength and hysteresis behavior of these columns under moderate and severe earthquake excitations. A comprehensive study has been conducted to investigate the strength of SRCFT columns reinforced with castellated and traditional cruciform steel sections, made with thin-walled, welded I-section. The paper describes and presents the results of the testing of four small size (155 mm*155 mm) and short column specimens. The experimental results indicate that the new steel section causes high strength and better post yield behavior of SRCFT columns, because of the increase of shear and bending strength, torsion resistance and interaction between the hollow steel section and concrete. I...
Journal of Structural Fire Engineering
Purpose The primary purpose of this research was to expand the knowledge base regarding the behav... more Purpose The primary purpose of this research was to expand the knowledge base regarding the behavior of steel columns during exposure to fire. This paper presents the numerical study of the effect of heat on the performance of parking steel column in a seven-story steel building under cyclic loading. Design/methodology/approach In this research, the forces and deformations developed during a fire are estimated by using detailed 3D finite-element models. The analyses are in the form of a coupled thermo-mechanical analysis in two types of loading: concurrent loading (fire and cyclic loading) and non-concurrent loading (first fire and then cyclically), and the analyses have been conducted in both states of the fire loading with cooling and without cooling using the ABAQUS software. Further, it was investigated whether, during the fire loading, the specimen was protected by a 3-cm-thick concrete coating and how much it changes the seismic performance. After verification of the specimen with the experimental test results, the column model was investigated under different loading conditions. Findings The result of analyses indicates that the effect of thermal damage on the performance of steel columns, when cooling is happening late, is more than the state in which cooling occurs immediately after the fire. In this paper, thermal–seismic performance of parking steel columns has been specified and the effect of the fire damage has been investigated for the protected steel by concrete coating and to the non-protected steel, under both cooling and non-cooling states. Originality/value This study led to recommendations based on the findings and suggestions for additional work to support performance-based fire engineering. It is clear that predicting force and deformation on steel column during fire is complex and it is affected by many variables. Here in this paper, those variables are examined and proper results have been achieved.
Journal of Urban and Environmental Engineering
Based on some findings on the two kinds of Concrete Filled Double Skin steel Tube (CFDST) members... more Based on some findings on the two kinds of Concrete Filled Double Skin steel Tube (CFDST) members with circular or square sections, a new kind of CFDST with octagonal and polygonal section have been investigated under axial and cyclic loading. For this purpose, the outer steel wall has various steel shapes and the inner steel wall is the same as circular section and for some part of analyses, the outer tube is the same as circular section and the inner wall has various steel sections. Primarily, FEM procedure has been verified with some available experimental studies and then, seven composite columns with different section types have been analyzed. The results of analyses exhibited the increase in strength and improvement in hysteresis behavior of the proposed steel sections under cyclic loading.
Istrazivanja i projektovanja za privredu
Concrete Filled Double Skin Steel Tubular (CFDST) columns could be considered as a new type of co... more Concrete Filled Double Skin Steel Tubular (CFDST) columns could be considered as a new type of concrete filled steel tubular (CFT) columns. These columns are composed of two steel tubes in the concentric configurations with concrete between them. In the current study, finite element method was used to analyze the effects of load application, type of material, and geometric parameters of the specimens. It was found that the results obtained from finite element analysis show good agreement with available experimental results. Findings of the current study clearly indicate the high ductility and strength of CFDST columns under axial loading. The results show the significant impact of yield stress of steel section, compressive strength of concrete, thickness and diameter variations on the strength and ductility of CFDST columns.
International Journal of Advanced Structural Engineering
SRCFT columns are formed by inserting a steel section into a concrete-filled steel tube. These ty... more SRCFT columns are formed by inserting a steel section into a concrete-filled steel tube. These types of columns are named steel-reinforced concrete-filled steel tubular (SRCFT) columns. The current study aims at investigating the various types of reinforcing steel section to improve the strength and hysteresis behavior of SRCFT columns under axial and lateral cyclic loading. To attain this objective, a numerical study has been conducted on a series of composite columns. First, FEM procedure has been verified by the use of available experimental studies. Next, eight composite columns having different types of cross sections were analyzed. For comparison purpose, the base model was a CFT column used as a benchmark specimen. Nevertheless, the other specimens were SRCFT types. The results indicate that reinforcement of a CFT column through this method leads to enhancement in load-carrying capacity, enhancement in lateral drift ratio, ductility, preventing of local buckling in steel shell, and enhancement in energy absorption capacity. Under cyclic displacement history, it was observed that the use of cross-shaped reinforcing steel section causes a higher level of energy dissipation and the moment of inertia of the reinforcing steel sections was found to be the most significant parameter affecting the hysteresis behavior of SRCFT columns.
World Journal of Engineering