Seismic Performance And Its Experimental Study Of Vertically Stiffened And Vertically Connected Steel Plate Shear Wall Structure

Steel plate shear wall(SPSW)is known as an effective lateral force resisting system in high seismic zones.The main function of SPSW is to resist horizontal story shear and overturning moment due to lateral loads.In general,a SPSW system consists of a steel plate wall,two boundary columns and horizontal floor beams.In this thesis,the key technology of steel structure engineering was taken as the entry point.Combined with the development trend and performance characteristics of steel plate shear wall(SPSW),a new type of SPSW,vertically stiffened and vertically connected SPSW(W-SPSW)is proposed,which is connected with frame beam only by bolts or welding in the vertical direction.The flexible adjustment of a gap between the wallboard and frame column allows one to avoid the adverse effect of tensile stress generation in the frame column,which has much higher compressive strength,as compared to tensile one.The vertical edge steel stiffeners are located at the sides and the middle of the plate,which simplifies the structure design.In this study,the elastic stability loss/buckling resistance and hysteretic behavior of this new type of W-SPSW,as well as the seismic performance of embedded VV-SPSW with the structure of planar steel frames are systematically investigated via a theoretical-and-experimental technique-and-numerical simulation.The detailed content and main results of this study are as follows:(1)To study the elastic stability loss resistance of W-SPSW under axial compression and shear loading conditions,the numerical simulations via the finite element method were combined with theoretical calculations and yielded the elastic bucking bearing capacity and its influence factors,stiffness ratio of finite ribbed plate,and suitable range of height-to-width ratio of this VV-SPSW for the above two loading conditions.The elastic buckling coeff-icient values for different boundary conditions,such as free sides,restriction on single side plane displacements,as well as side-restrained with 1-4 evenly spaced vertical plane displacement lines in the middle were computed for the above two loading conditions The calculation formulas for the stiffness ratio of finite ribbed plate for the side stiffening rib and 1-4 stiffening ribs evenly spaced set in the middle under two types of stress conditions were derived,respectively.The integral and intercostal suitable ranges of height-to-width ratios for SPSW based on the elastic buckling analysis under the above conditions were assessed.The influence factors of SPSW elastic buckling performance and the method for improving its critical buckling stress were analyzed.(2)The calculation formula for the initial lateral stiffness of a single SPSW with a stiffening rib was derived.A comparative analysis of the finite element analysis results with those yielded by calculation formula has revealed their good fit.The dependences between the initial lateral stiffness of SPSW and such factors as non-uniform coefficient of shear stress,influence coefficient of stiffening rib end-constraint,bending moment,steel plate thickness and height-to-width ratio,as well as cross-sectional area,and number of stiffening ribs,are discussed.A brief comparison of the three different methods for improving the initial lateral stiffness of SPSW is made,and several options on SPSW construction improvement measures are provided based on the initial lateral stiffness criterion.(3)For investigation of hysteretic behavior of a single VV-SPSW under horizontal load,the finite element analysis was used,yielding the mechanical performance indices of VV-SPSW,including hysteretic curve,skeleton curve,energy dissipation coefficient,and stiffness degradation coefficient.The influence factors and variation patterns of the hysteretic curve,dissipation capacity,and stiffness degradation behavior were analyzed.The nonlinear hysteretic characteristics of this type of VV-SPSW were revealed.The performed research has revealed that a single VV-SPSW subjected to a horizontal load exhibited a high bearing capacity and initial lateral stiffness.The tensile stress zone was formed along the diagonal direction in the post-yielding deformation process in SPSW,which would sequentially bear the horizontal load and consume the supplied energy.Thus,it is shown to possess a strong plastic deformation capacity and ability of energy dissipation,as well as good seismic performance.(4)For investigation of the seismic performance of embedded VV-SPSW with a planar steel frame structure,a combination of experimental research with the finite element analysis was used to analyze the quasi-static pulsed loading of finite-element models of 4 embedded VV-SPSW test pieces,with 1:3 three-story and three-span structures of planar steel frames.The seismic performance and damage accumulation law of this new structure were systematically investigated and demonstrated its high seismic capacity,good deformability and energy dissipation characteristics,which are vital in case of earthquake.In reasonably designed planar steel frame structure with the embedded VV-SPSW,the latter can be the first seismic fortification line.The damage accumulation law of the integral structure fully complies with the design ideology of multiple seismic fortification lines and the seismic design requirements of the "strong frames-weak wallboard" and "strong column-weak beam" concepts.