Seismic Behavior And Experimental Study Of Steel Plate Shear Wall With Oblique Channel Stiffeners

Steel plate shear wall(SPSW)is a new type of seismic structure with good ductility,lateral resistance,and energy dissipation capacity,and SPSW is very suitable for buildings in high-intensity areas.Flat-shaped stiffeners are usually used to improve the performance of the steel plate shear wall.However,flat stiffeners cause torsion and bending failure during loading,which could lead to the reduction of the stiffening effect.This paper proposed a new type of SPSW that the channel-shaped stiffeners arranged along the diagonal of the steel plate.This type of SPSW has high elastic buckling load,small out-of-plane deformation,high lateral bearing capacity and initial stiffness,and strong energy dissipation capacity.The elastic buckling performance,lateral resistance,hysteretic performance,and design theory of SPSWs with oblique channel stiffeners are studied by means of theoretical derivation,experimental research,and numerical simulation.The main research contents and results are as follows:(1)Through the finite element method,the effects of parameters on the shear and axial compression buckling behavior of the stiffened plate are studied.Considering the rotational constraint of channel stiffener on the stiffening edge of the steel plate,the second threshold stiffness is put forward,and the formulas for calculating the threshold stiffness and the second threshold stiffness with good accuracy are fitted.The results show that when the stiffener-plate stiffness ratio reaches the second threshold stiffness,the stiffener can completely restrain the out-of-plane displacement and rotation of the stiffening edge of the plate,and when increasing the torsion-bending stiffness ratio,the threshold stiffness can be effectively reduced.It is suggested that the torsion-bending stiffness ratio not less than 0.307 when the steel plate is obliquely stiffened with channel stiffeners.For the steel plate with a large span-height ratio,it is recommended to arrange stiffeners in the square sub-plate.(2)In order to investigate the hysteretic behavior,force mechanism,plastic mechanism,and failure mode of different forms of SPSWs with oblique channel stiffeners under cyclic load,quasi-static tests were carried out on 6 one-span two-story 1/3 scaled SPSW specimens.The influence of oblique channel stiffeners on the seismic behavior and internal force of steel plate shear walls is analyzed.The results show that the oblique channel stiffeners can obviously improve the elastic buckling load,lateral bearing capacity,stiffness,and energy dissipation capacity of the structures.Furthermore,there is no torsion or bending failure of the stiffeners.Oblique stiffener has a great additional effect on the boundary element,which can not be ignored in the design.(3)The lateral resistance and hysteretic behavior of oblique channel stiffened SPSWs under pushover and cyclic load are studied by the finite element method.Firstly,the pushover performance of the oblique channel stiffened SPSW is analyzed.Secondly,the finite element models of the 6 specimens are established.The stress development,out-of-plane deformation,and plastic accumulation of the specimens are analyzed.Based on the test models,the seismic performance indexes,stress,deformation,and economy of 15 different forms of steel plate shear walls are compared systematically.The results show that the steel plate shear wall with oblique channel stiffeners is an excellent type of SPSW which with a good seismic performance index and high economy.(4)The cross brace-strip model(CBSM)is proposed to simulate the lateral resistance of SPSWs with oblique stiffeners and solves the time-consuming problems of calculation and design when using detailed models.The finite element model of CBSM is established and verified with the theoretical results of bearing capacity and initial stiffness.The results show that the formula of the initial stiffness is in good agreement with the detailed model.The initial stiffness predicted by CBSM is lower than that of the detailed model,and the error is less than 15%,which is on the safe side.The bearing capacity predicted by CBSM is in good agreement with the results of theoretical formula and detailed model,which means CBSM can greatly shorten the calculation time,facilitate the design calculation of practical engineering,and improve the design efficiency.(5)In order to study the maximum response of oblique channel stiffened SPSW structures in the rare earthquake and better apply it to practical engineering,the design method of this kind of steel plate wall is put forward.Based on a practical project,the elastoplastic time history analysis of an SPSW structure with oblique channel stiffeners is carried out.The results show that this structure has excellent seismic performance.Under the rare earthquake,the structure is safe and stable,and each index meets the requirements of the code,which is suitable for multi-storey and tall buildings.