Experimental Study On Zoning Technology And Seismic Performance Of Long Span Steel Frame Infill Walls

Frame exterior wall or partition wall has always been considered as "non-structural member" and "the first line of defense against earthquake".However,the initial stiffness of frame filled with wallboard will be several times higher than that of empty frame.At the same time,the cost of wall post-earthquake repair is higher,and the uncertainty of internal and external response of traditional masonry filled wall and its irregular overall layout will be harmful due to the excessive strength of masonry.Safety and ductility of buildings.For example,"short column failure","weak layer failure","torsional failure" and so on.At the same time,the higher the damage in the wall plane,the smaller the bearing capacity outside the wall plane.Therefore,in recent years,the demand for cost control of post-earthquake repair has led to higher and higher requirements for wall damage control.Following Majid Mohammadi's first application of transverse zoning technology in filled steel frame walls in 2010,some scholars have made some achievements in the research of wall zoning technology.The frame-filled wall with wall partitioning technology has the advantages of low damage,low cost,simple structure,high out-of-plane bearing capacity,stable seismic performance and good ductility,and has broad application prospects.After consulting a large number of literatures,it is found that few scholars have studied the long-span partitioned infilled walls with open doors and large windows.Taking the steel frame infilled walls with a net span of 5.1m as an example,the main research contents and achievements are as follows:(1)A simplified wall partition construction technology suitable for long-span frame structures is developed.Vertical zoning technology is the main technology,while horizontal zoning is the auxiliary technology.This technology can provide reference for assembly application of partitioned frame infilled wall.(2)Three full-scale single-storey and single-span steel frame infilled wall specimens were constructed by means of transverse or vertical zoning.Three specimens and empty frame specimens were tested under repeated low-cycle loading.The crack development,damage mechanism and energy dissipation mode of the wall were analyzed.The test results show that the damage of steel frame infilled wall with vertical zoning technology is obviously lower than that with transverse zoning technology.At the same time,the new simplified construction technology of frame infilled wall specimens has stable seismic performance,low damage characteristics and good out-of-plane collapse resistance.(3)The prediction model of out-of-plane bearing capacity of transverse partitioned infilled walls under rigid boundary conditions is deduced by mechanical formula,and a simplified version of three-fold line model of out-of-plane bearing capacity is proposed,which can predict the cracking bearing capacity,ultimate bearing capacity and maximum displacement of the wall with complete failure.The developed theoretical model takes into account the influence of various parameters such as wall thickness,compressive strength of masonry,bond strength between masonry and mortar,wall height and net span of filling wall,which is convenient for designers to design partitioned filling wall.