Theoretical And Experimental Research On Seismic Performance Of Steel Plate Shear Wall With Self-centering Energy Dissipation Braces And Its Structure

Steel plate shear wall is a kind of lateral force resisting system with good ductility and strong energy dissipation capability,which can provide stable lateral stiffness for the structure and dissipate seismic energy during earthquakes.However,steel plate shear walls dissipate energy by the yield of steel.Obivious residual deformations are produced due to the accumulated plastic deformances after the earthquake,which will bring difficulties the repair of the structure.Meanwhile,the tension field developed in the wall plate has adverse effects on the boundary column.Therefore,a new type of steel plate shear wall with self-centering energy dissipation braces(SPSW-SCEDB)with high energy dissipation and self-centering performance is proposed in this study.SPSW-SCEDB is composed of steel wall plate connected to beams only,which is located on the middle,and two self-centering energy dissipation(PS-SCED)braces,which are arranged symmetrically and obliquely on two sides of the wall plate.SPSW-SCEDB shows flag-shaped hysteretic curves under cyclic loading.In this study,the hysteretic behavior,energy dissipation and self-centering capabilities of SPSW-SCEDB are systematically studied through theoretical analysis,numerical simulation and quasi-static tests.The design method for SPSW-SCEDB is developed.The performance requirements of steel frame-shear plate shear wall with self-centering energy dissipation braces(SF-SCSPSW)structure are given,and the direct displacement-based seismic design method for structure is established.The main research contents and conclusions are summarized as follows:(1)A SPSW-SCEDB composed of wall plate and self-centering energy dissipation braces is proposed,which has high energy dissipation and self-centering performance.The theoretical calculation formulas of its stiffness and bearing capacity are presented through the analysis of its working principle under lateral force.The hysteretic performance and parameter sensitivity of SPSW-SCEDB are simulated based on the finite element models.The results show that the SPSW-SCEDB exhibits a stable and full flag-shaped hysteretic response under the combined action of wall plate and braces.SPSW-SCEDB has full self-centering capability when the horizontal remaining restoring force of braces can completely overcome the compressive bearing capacity of wall plate.According to the simulated results,the approximate formula for calculating the compressive bearing capacity of wall plate is established.The results of parameter sensitivity analysis show that the width-to-height ratio of wall plate,height-to-thickness ratio of wall plate and friction force of brace have great influence on the hysteretic performances of SPSW-SCEDB,which are the main design parameters.The pre-pressed force,initial stiffness and second stiffness of brace can be set as fixed values to simplify the design process.(2)The cyclic loading tests were conducted on one disc spring device,one friction device,two self-centering energy dissipation braces,four specimens with braces only,two specimens with wall plate only and SPSW-SCEDB specimens with different wall plate thickness,wall plate width and friction force of brace.The self-centering and energy dissipation capabilities,and stability of disc spring device,friction device and braces are studied.The interaction between wall plate and braces,and the influence of main design parameters on hysteretic performance of SPSW-SCEDB are analyzed.The experimental results show that the SPSW-SCEDB has stable flag-shaped hysteretic curves with good self-centering capability while maintaining high initial stiffness,strength and energy dissipation.The parallel relationship between wall plate and braces is verified.The ultimate bearing capacity of the SPSW-SCEDB predicted by the equation is slightly larger than the experimental value.The wall plate provides the main energy dissipation capability for SPSW-SCEDB,and PS-SCED braces provide complete self-centering capability and supplement energy dissipation capability for SPSW-SCEDB.The design parameters of SPSW-SCEDB have no obvious effect on the out-of-plane deformation of the wall plate.The energy dissipation and post-yield stiffness of SPSW-SCEDB increase with the increase of wall plate thickness and width.The excessive wall plate width may lead to the increase of the brace inclination angle,which is adverse to the bearing capacity and self-centering capability of SPSW-SCEDB.When the ratio of the horizontal remaining restoring force of the braces to the compressive bearing capacity of the wall plate is greater than 1.3,the residual drift ratio of SPSW-SCEDB is less than 0.5%,indicating that the SPSW-SCEDB has a good self-centering capability.The friction force of brace has a positive effect on the energy dissipation of the SPSW-SCEDB.However,the influence of the friction force is smaller than that of the size of the wall plate.(3)Based on the working mechanism and experimental results of the SPSW-SCEDB,a combined strip model is established,which can consider the effect of bolted connection of the wall plate.The simulated and the experimental hysteretic curves are compared and verified,and the ultimate bearing capacity equation of the SPSW-SCEDB is revised based on the model.The equations for the axial force,shear force and bending moment distributions on the beam are established,and the influence of design parameters on the bending moment distribution are studied by orthogonal experiments.Results indicate that the effect of the wall plate thickness and the activation force of braces on the bending moment is greater than the wall plate width,the initial stiffness and the second stiffness of the braces.The smaller activation force of braces and the thicker wall plate can effectively protect the beam sections at the brace connections.Based on the test results and parametric analysis results of the SPSW-SCEDB,the design method for SPSW-SCEDB is proposed,and the specific design process and suggestions are given.(4)The performance requirements of the SF-SCSPSW structure under the different level earthquakes are given.The structure should meet the state requirements of fully serviceable,serviceable after repair,life safety and collapse prevention under frequent,medium,large and mega earthquakes,respectively.The limit values of the drift ratio and the residual drift ratio are explained.The direct displacement-based seismic design method for SF-SCSPSW structure is established,and the specific design process is also provided.It is suggested that 75% and 25% of the inter-story shear force are resisted by the SPSW-SCEDB and the frame,respectively.8-and 15-story SF-SCSPSW structures are designed and modeled to analyze the structural responses under the frequent,moderate,large,and mega earthquakes.Results demonstrate that the SPSW-SCEDBs in the two structures meet the working states of elastic,mild,moderate and severe damage under frequent,moderate,large and mega earthquakes,respectively.The beams remain elastic under large earthquake,while the local yield occurs under mega earthquake.The yield occurs between the brace connection and the column,while the columns always maintain elastic.The inter-story displacement,residual deformation,and strain responses of beams and columns meet the seismic performance requirements.The availability of the design method is verified.