Based on the failure model of building structural steels under earthquake loading, the low cycle fatigue test at constant strain, the stochastical fatigue test under real earthquake load spectrum and the structural fa...Based on the failure model of building structural steels under earthquake loading, the low cycle fatigue test at constant strain, the stochastical fatigue test under real earthquake load spectrum and the structural fatigue test are carried out. The experimental results show that microalloying of V Ti and Nb can improve the anti-seismic propersties of steel bars. In the high strain and shori life range, both the static strength and ductility of steels are very important to increasing the low cycle fatigue resistance of steels.展开更多
Reponses of structures subjected to severe earthquakes sometimes significantly surpass what was considered in the design.It is important to investigate the failure mechanism and collapse margin of structures beyond de...Reponses of structures subjected to severe earthquakes sometimes significantly surpass what was considered in the design.It is important to investigate the failure mechanism and collapse margin of structures beyond design,especially for high-rise buildings.In this study,steel high-rise buildings using either square concrete-filled-tube(CFT) columns or steel tube columns are designed.A detailed three-dimensional(3 D) structural model is developed to analyze the seismic behavior of a steel high-rise towards a complete collapse.The effectiveness is verified by both component tests and a full-scale shaking table test.The collapse margin,which is defined as the ratio of PGA between the collapse level to the design major earthquake level(Level 2),is quantified by a series of numerical simulations using incremental dynamic analyses(IDA).The baseline building using CFT columns collapsed with a weak first story mechanism and presented a collapse margin ranging from 10 to 20.The significant variation in the collapse margin was caused by the different characteristics of the input ground motions.The building using equivalent steel columns collapsed earlier due to the significant shortening of the locally buckled columns,exhibiting only 57% of the collapse margin of the baseline building.The influence of reducing the height of the first story was quite significant.The shortened first story not only enlarged the collapse margin by 20%,but also changed the collapse mode.展开更多
In this paper,the potential of utilizing improved metaheuristic approaches in optimal design of building structures is concerned.In this regard,the drift-tribe-charged system search algorithm is proposed that the posi...In this paper,the potential of utilizing improved metaheuristic approaches in optimal design of building structures is concerned.In this regard,the drift-tribe-charged system search algorithm is proposed that the position and velocity updating processes of the charged system search is developed by implementing the mathematical presentation of the free-electron model utilized for metal conductors.In addition,the searching phase of the developed algorithm is also divided into three separate phases in order to improve the convergence capability of the algorithm.By means of these modifications,the exploitation and exploration rates of the standard algorithm are enhanced.In order to determine the ability of the proposed improved metaheuristic method considering some complex optimization problems,a 10-story steel building structure with 1026 structural members alongside a 60-story structure with 8272 members are utilized as numerical examples.The overall capability of the developed metaheuristic approach is compared with other metaheuristics.A total number of 30 independent runs have been conducted for each of the standard and proposed methods while a statistical analysis is also conducted for comparative purposes.The obtained optimum results demonstrated that the proposed metaheuristic approach is capable of preparing better outcomes than other metaheuristics.展开更多
Iron & Steel Industry China's outputs of crude steel, steel products, coke and ferrous alloys in 2012 were 716.54 million tons (up 3.1% YOY), 051.86 million tons (up 7.7% YOY), 443.23 million tons (up 5.2% YOY...Iron & Steel Industry China's outputs of crude steel, steel products, coke and ferrous alloys in 2012 were 716.54 million tons (up 3.1% YOY), 051.86 million tons (up 7.7% YOY), 443.23 million tons (up 5.2% YOY) and 31.29 million tons (up 15% YOY),展开更多
An inelastic material model that was previously developed by the author for standard W-Shapes was adapted for use to model the behavior and strength of rotary-straightened hot rolled W-Shape sections.Using a published...An inelastic material model that was previously developed by the author for standard W-Shapes was adapted for use to model the behavior and strength of rotary-straightened hot rolled W-Shape sections.Using a published residual stress model for these W-Shapes,limit load analyses were conducted using the material model in MASTAN2 and were compared with published finite element results.The material model required an adjustment to the initial yield moment conditions and residual stress ratios.Comparisons with published results indicate that these minor modifications were sufficient to provide very good modeling agreement.The previously developed material model can be used effectively to model the limit load conditions of rotary-straightened hot rolled W-Shape beams and beam-columns in steel frames.The effect of rotary-straightening W-Shapes is more significant for minor axis bending conditions and this becomes more pronounced as the floor load magnitudes increase.展开更多
The properties of the carbonated brick made of steel slag-slaked lime mixture such as strength, drying shrinkage, water absorption and soundness were mainly investigated. The experimental results indicate that, after ...The properties of the carbonated brick made of steel slag-slaked lime mixture such as strength, drying shrinkage, water absorption and soundness were mainly investigated. The experimental results indicate that, after carbonation, the strength of the brick increases, its drying shrinkage reduces, and its soundness becomes eligible. The optimal slaked lime/steel slag(SL/SS) ratio for the carbonated brick is 0.2 and the asprepared brick meets the requirements of the Chinese standard for MU20-grade building bricks, additionally, it also demonstrates prominent environmental benefits. The XRD and pore structure analyses indicate that the excellent properties of this carbonated brick are attributed to the formation of carbonate crystals and the dense structure due to the carbonation.展开更多
A full-scale, two-story, two-by-one bay, steel braced-frame was subjected to a number of unidirectional ground motions using three shake tables at the UNR-NEES site. The test-bed frame was designed to study the seismi...A full-scale, two-story, two-by-one bay, steel braced-frame was subjected to a number of unidirectional ground motions using three shake tables at the UNR-NEES site. The test-bed frame was designed to study the seismic performance of nonstructural systems including steel-framed gypsum partition walls, suspended ceilings and fire sprinkler systems. The frame can be configured to perform as an elastic or inelastic system to generate large floor accelerations or large inter story drift, respectively. In this study, the dynamic performance of the linear and nonlinear test-beds was comprehensively studied. The seismic performance of nonstructural systems installed in the linear and nonlinear test-beds were assessed during extreme excitations. In addition, the dynamic interactions of the test-bed and installed nonstructural systems are investigated.展开更多
The analysis of spliced column has been carried out to detect optimum location of providing splices in the column.In the present work,static and dynamic(free vibration)analyses of spliced column have been done by rand...The analysis of spliced column has been carried out to detect optimum location of providing splices in the column.In the present work,static and dynamic(free vibration)analyses of spliced column have been done by randomising the location of splicing.A symmetrical four storey steel framed building has been modelled,analysed and designed for loads(dead,live and earthquake loads)recommended by Indian Codal provisions using Staad.Pro.The critical column at each floor level is identified based on axial force(AF),bending moment(BM)and shear force(SF).The total 16 models of spliced columns have been designed and then modelled in a 3D CAD Design tool(SOLIDWORKS)and then imported in the finite element tool(ANSYSWorkbench 14.0)for detailed analysis.The variation of stress,strain and deflection of the spliced column are shown in the form of contour.Further,the modal analysis is performed to determine the natural frequencies.The results of static and dynamic analyses are compared for each modelled spliced column to obtain the optimum location for providing splices in the column.The dynamic analysis of spliced column is of utmost importance in the region where dynamic loadings like earthquake,cyclones etc.are more frequent,and mere static analysis does not account for the safety of the structure.This study will help the engineers to select directly the optimum size and location of the splices in the column of a steel framed building.展开更多
文摘Based on the failure model of building structural steels under earthquake loading, the low cycle fatigue test at constant strain, the stochastical fatigue test under real earthquake load spectrum and the structural fatigue test are carried out. The experimental results show that microalloying of V Ti and Nb can improve the anti-seismic propersties of steel bars. In the high strain and shori life range, both the static strength and ductility of steels are very important to increasing the low cycle fatigue resistance of steels.
基金Heilongjiang Province Application Technology Research and Development under Grant No.GX16C007National Key Research and Development Program of China under Grant No.2017YFC1500605
文摘Reponses of structures subjected to severe earthquakes sometimes significantly surpass what was considered in the design.It is important to investigate the failure mechanism and collapse margin of structures beyond design,especially for high-rise buildings.In this study,steel high-rise buildings using either square concrete-filled-tube(CFT) columns or steel tube columns are designed.A detailed three-dimensional(3 D) structural model is developed to analyze the seismic behavior of a steel high-rise towards a complete collapse.The effectiveness is verified by both component tests and a full-scale shaking table test.The collapse margin,which is defined as the ratio of PGA between the collapse level to the design major earthquake level(Level 2),is quantified by a series of numerical simulations using incremental dynamic analyses(IDA).The baseline building using CFT columns collapsed with a weak first story mechanism and presented a collapse margin ranging from 10 to 20.The significant variation in the collapse margin was caused by the different characteristics of the input ground motions.The building using equivalent steel columns collapsed earlier due to the significant shortening of the locally buckled columns,exhibiting only 57% of the collapse margin of the baseline building.The influence of reducing the height of the first story was quite significant.The shortened first story not only enlarged the collapse margin by 20%,but also changed the collapse mode.
基金Supported by:Research Grant of the University of Tabriz under Grant No.1105。
文摘In this paper,the potential of utilizing improved metaheuristic approaches in optimal design of building structures is concerned.In this regard,the drift-tribe-charged system search algorithm is proposed that the position and velocity updating processes of the charged system search is developed by implementing the mathematical presentation of the free-electron model utilized for metal conductors.In addition,the searching phase of the developed algorithm is also divided into three separate phases in order to improve the convergence capability of the algorithm.By means of these modifications,the exploitation and exploration rates of the standard algorithm are enhanced.In order to determine the ability of the proposed improved metaheuristic method considering some complex optimization problems,a 10-story steel building structure with 1026 structural members alongside a 60-story structure with 8272 members are utilized as numerical examples.The overall capability of the developed metaheuristic approach is compared with other metaheuristics.A total number of 30 independent runs have been conducted for each of the standard and proposed methods while a statistical analysis is also conducted for comparative purposes.The obtained optimum results demonstrated that the proposed metaheuristic approach is capable of preparing better outcomes than other metaheuristics.
文摘Iron & Steel Industry China's outputs of crude steel, steel products, coke and ferrous alloys in 2012 were 716.54 million tons (up 3.1% YOY), 051.86 million tons (up 7.7% YOY), 443.23 million tons (up 5.2% YOY) and 31.29 million tons (up 15% YOY),
文摘An inelastic material model that was previously developed by the author for standard W-Shapes was adapted for use to model the behavior and strength of rotary-straightened hot rolled W-Shape sections.Using a published residual stress model for these W-Shapes,limit load analyses were conducted using the material model in MASTAN2 and were compared with published finite element results.The material model required an adjustment to the initial yield moment conditions and residual stress ratios.Comparisons with published results indicate that these minor modifications were sufficient to provide very good modeling agreement.The previously developed material model can be used effectively to model the limit load conditions of rotary-straightened hot rolled W-Shape beams and beam-columns in steel frames.The effect of rotary-straightening W-Shapes is more significant for minor axis bending conditions and this becomes more pronounced as the floor load magnitudes increase.
基金Funded by the"Eleventh Five-year Plan"for Sci&Tech Research of China(NO.2006BAF02A24)
文摘The properties of the carbonated brick made of steel slag-slaked lime mixture such as strength, drying shrinkage, water absorption and soundness were mainly investigated. The experimental results indicate that, after carbonation, the strength of the brick increases, its drying shrinkage reduces, and its soundness becomes eligible. The optimal slaked lime/steel slag(SL/SS) ratio for the carbonated brick is 0.2 and the asprepared brick meets the requirements of the Chinese standard for MU20-grade building bricks, additionally, it also demonstrates prominent environmental benefits. The XRD and pore structure analyses indicate that the excellent properties of this carbonated brick are attributed to the formation of carbonate crystals and the dense structure due to the carbonation.
基金National Science Foundation under Grant No.0721399
文摘A full-scale, two-story, two-by-one bay, steel braced-frame was subjected to a number of unidirectional ground motions using three shake tables at the UNR-NEES site. The test-bed frame was designed to study the seismic performance of nonstructural systems including steel-framed gypsum partition walls, suspended ceilings and fire sprinkler systems. The frame can be configured to perform as an elastic or inelastic system to generate large floor accelerations or large inter story drift, respectively. In this study, the dynamic performance of the linear and nonlinear test-beds was comprehensively studied. The seismic performance of nonstructural systems installed in the linear and nonlinear test-beds were assessed during extreme excitations. In addition, the dynamic interactions of the test-bed and installed nonstructural systems are investigated.
文摘The analysis of spliced column has been carried out to detect optimum location of providing splices in the column.In the present work,static and dynamic(free vibration)analyses of spliced column have been done by randomising the location of splicing.A symmetrical four storey steel framed building has been modelled,analysed and designed for loads(dead,live and earthquake loads)recommended by Indian Codal provisions using Staad.Pro.The critical column at each floor level is identified based on axial force(AF),bending moment(BM)and shear force(SF).The total 16 models of spliced columns have been designed and then modelled in a 3D CAD Design tool(SOLIDWORKS)and then imported in the finite element tool(ANSYSWorkbench 14.0)for detailed analysis.The variation of stress,strain and deflection of the spliced column are shown in the form of contour.Further,the modal analysis is performed to determine the natural frequencies.The results of static and dynamic analyses are compared for each modelled spliced column to obtain the optimum location for providing splices in the column.The dynamic analysis of spliced column is of utmost importance in the region where dynamic loadings like earthquake,cyclones etc.are more frequent,and mere static analysis does not account for the safety of the structure.This study will help the engineers to select directly the optimum size and location of the splices in the column of a steel framed building.