Study On Seismic Behavior Of Fabricated Steel Staggered Truss System

The prefabricated steel structure staggered truss has the advantages of green environmental protection,convenient construction and high structural strength.It is a hot research topic at home and abroad,and can meet the needs of actual engineering development,and solve the problems of low steel structure buildings in China and overproduction of steel.In order to solve the poor performance of traditional staggered truss structure in energy dissipation and anti-overturning ability,this paper proposes a new fabricated steel frame-staggered truss structure scheme.Based on the investigation and research of domestic research status,summarize and analyze the suitability of steel structure staggered truss for seismic analysis Methods,and established four numerical simulation models of steel structure staggered truss system through finite element analysis software SAP2000,including: 19 m hybrid staggered truss structure,19 m hybrid staggered truss structure plus single frame structure,19 m open web staggered truss structure and 19 m open web staggered truss structure The truss structure plus the unilateral frame structure,through modal analysis,static elastoplastic analysis and dynamic elastoplastic analysis,the following conclusions can be obtained:(1)The first 20 modes of the four models are obtained through modal analysis,and the results show that the design of each model is related to the specification requirements.According to the mass participation coefficient of the model,it can be seen that the first three modes of the hybrid staggered truss structure is different from that of the hollow staggered truss structure,and the increase of the side span does not change the first three modes of the structure.The natural vibration periods of the four models gradually decrease with the increase of the mode shape.The natural vibration period of the open-web staggered truss structure is significantly greater than that of the hybrid staggered truss structure,indicating that the stiffness of the hybrid staggered truss structure are greater than that of the open-web staggered truss structure.In addition,the increase of the side span structure can effectively enhance the stiffness and torsional stiffness of the open-web staggered truss structure in the Y direction(vertical frame direction).(2)Through Pushover analysis of four staggered truss structure models,during the static pushover process in the X direction(transverse staggered truss direction),the end shear and displacement of the hybrid staggered truss structure are basically the same as those of the open-web staggered truss structure,and the difference is mainly reflected in the static thrust in the Y direction.Push the overturning process.The performance points of the four models are compared and analyzed.During the static pushover process in the X direction,the pushover performance of the 19 m hybrid staggered truss structure plus side span is significantly better than the other three structures,followed by the 19 m open web staggered truss structure plus side span,The 19 m hybrid staggered truss structure and the 19 m open web staggered truss structure;in the Y direction static pushover process,the pushover performance of the 19 m hybrid staggered truss structure plus side span is also better than the other three structures,followed by the 19 m hybrid staggered truss structure,19 m open web staggered truss structure plus side span and19 m open web staggered truss structure.In addition,the development and changes of the plastic hinges of the four models are basically the same.They only appear on the beams,and the plastic hinges have not yet appeared on the columns,which meets the seismic design requirements of "strong columns and weak beams".The new structure form "frame-staggered truss steel structure" enhances the reliability of the continuity of traditional staggered truss steel structure against collapse.Under the action of horizontal load,the frame-staggered truss steel structure truss joint members yield first,and as the load increases,the frame beams also yield.This type of damage is similar to a frame-shear wall structure,which forms multiple seismic lines of defense.(3)Through dynamic elastoplastic time history analysis of the structure,the seismic performance of the staggered truss structure under earthquake action is studied.The results show that the seismic performance of the four staggered truss structures in the X direction is basically the same,and the difference is mainly reflected in the seismic resistance in the Y directionperformance.Comparing the seismic performance of the four structures,the seismic performance of the 19 m hybrid staggered truss structure plus side span is significantly better than the other three structures,followed by the 19 m open web staggered truss structure plus side span,19 m hybrid staggered truss structure and 19 m open web staggered truss structure.