Experimental And Theoretical Study On Seismic Performance Of New Light Steel Fabricated Structure

Under the strategic background of vigorously developing fabricated structure in our country,the new light steel fabricated structure emerges as the times require with its advantages of light weight,high strength,and high degree of industrialization.This kind of structure is composed of cold-formed thin-walled steel wall embedded in steel frame,which belongs to steel frame with composite wall structure.The cold-formed thin-walled steel wall is used as the first seismic resistance line,and the steel frame is used as the second seismic resistance line,which has excellent seismic performance.At present,the research on the seismic performance of the new light steel fabricated structure at home and abroad mainly focuses on numerical simulation analysis,and few experimental studies are carried out.Therefore,the seismic performance of this kind of structure was tested and analyzed by means of finite element research in this paper.The main work is as follows:(1)The experimental research on a new light steel fabricated structure and two cold-formed thin-walled steel wall specimens under low cycle reciprocating load was carried out.The main indexes such as ductility,energy dissipation capacity,stiffness and bearing capacity were obtained.The main failure modes and energy dissipation mechanism of the specimens were investigated.The seismic performance of new light steel fabricated structure and cold-formed thin-walled steel wall were summarized and analyzed.(2)The material properties of cold-formed thin-walled section steel,hot-rolled section steel and bamboo wood carbon fiber board were studied,which provided reliable material properties data for subsequent finite element research.(3)By comparing the seismic performance of cold-formed thin-walled steel wall with or without bamboo wood carbon fiber board,the supporting effect of bamboo wood carbon fiber board on the wall is verified.(4)By comparing the mechanical performance of cold-formed thin-walled steel wall with or without the constraint of steel frame,and comparing the hysteretic performance of new light steel fabricated structure and steel frame with steel plate shear wall structure,it is verified that the cold-formed thin-walled steel wall becomes the core wall and can act as shear wall after being constrained by steel frame.(5)In view of the good fitting between the finite element calculation results and the test results,the new light steel fabricated structure model was established,the working mechanism of this kind of structure was described,and the coupling effect between steel frame and cold-formed thin-walled steel wall was discussed,which shows that the coupling effect can improve the seismic performance of the structure.Based on the analysis of the influence factors such as the thickness of cold-formed thin-walled steel frame,the thickness of bamboo wood carbon fiber board,vertical load,rigid diagonal brace,the section size of steel frame,the bearing capccity,lateral stiffness and energy dissipation of the structure were compared,a series of beneficial influence rules were obtained,the design method and design suggestions were given.(6)According to the experimental results on the seismic performance of new light steel fabricated structure,the four-fold-line hysteretic model was given to describe the hysteretic performance of this kind of structure.Based on the design simplification idea of steel frame with steel plate shear wall structure,the simplified design model of multi strip for the new light steel fabricated structure was given,and the calculation formula for the cross-sectional area of the diagonal strip was modified.