Studies On Unified Hysteresis Strip Model Of Unstiffened Steel Plate Shear Wall

As a new member of resisting lateral forces,Unstiffened Steel Plate Shear Wall(USPSW)have presented great lateral stiffness,high bearing capacity,excellent deformation and ductility,stable hysteresis performance in practical engineering applications.Usually,USPSW can be divided into three categories according to thickness ratio(?): thin plate shear wall(? > 300),mid-thick plate shear wall(100 < ? ? 300),and thick plate shear wall(? ? 100).The proposed simplified models of USPSW has some limitations,such as Modified Strip Model(MSM),Three Strip Model(TSM)and Combined Strip Model(2-8)which based on traditional Strip Model(SM)are only for thin plate shears.Although Unified Strip Model(USM)has solved the shortcomings of the traditional Strip Model to simulate the mid-thick and thick wall,it is slightly complicated,and the shear ratio coefficient is determined by regression.Therefore,based on the Strip Model,a new Unified Hysteresis Strip Model(UHSM)has been proposed for thin plate,mid-thick plate and thick plate shear wall in this paper.It is of great significance to modify the macro simplified model of USPSW and promote the application of USPSW in our country.The main research works are as follows:(1)The numerical simulation of the domestic and overseas typical completed USPSW tests have been done to clarify the hysteretic performance of USPSW and point out the limits of traditional SM and other simplified models.Based on this,the basic theory of the Unified Hysteresis Strip Model(UHSM)of USPSW is proposed by considering the F-D relationship of the strip and the contribution of compressive stress in the tension strips.(2)One-bay single story USPSW specimens with a rigid boundary frame were established where the boundary rigid members were hinge connected at the joints.By comparing the hysteresis curve,skeleton curve,stiffness curve and hysteresis energy dissipation of the micro finite element model and the macro simplified model,the UHSM was accurate enough to predict the static behaviors of USPSW without influence of boundary frame.Next,One-bay single story USPSW specimens were established where the joints of boundary members were rigid connection,the UHSM was accurate enough to predict the static behaviors of USPSW with the influence of boundary frame.(3)Multi-story USPSW specimens were established,it is verified that the UHSM was accurate enough to predict the static behaviors of multi-story USPSW specimens by comparing the hysteresis curve,skeleton curve,stiffness curve and hysteresis energy dissipation of the micro finite element model and the macro simplified model(4)The modal analysis of multi-story USPSW with micro finite element model and macro simplified model is adopted to prove UHSM can accurately reflect the period and mode of USPSW.Then,the dynamic elastic-plastic time history analysis of the specimen is carried out.It is verified that the UHSM was accurate enough to predict the dynamic behaviors of multi-story USPSW by comparing the vertex time history curve,the base shear time-history curve and the base shear-vertex displacement curve of the micro finite element model and the macro simplified model.