Research On Seismic Behavior Of Diagonally Stiffened Stainless Steel Plate Shear Wall

As a new type of building material,stainless steel has the advantages of excellent corrosion resistance,good ductility,attractive appearance and low life-cycle costs,leading to the broad application prospect.As a new type of lateral force resisting system,the steel plate shear wall has the advantages of excellent energy dissipation performance,light weight,flexible structural layout and convenient assembly construction,leading to bright development prospects.With the development of relevant research,stainless steel has been widely used in building structures.However,the current research on stainless steel structure mainly focuses on the static performance,there are few researches about the seismic performance of stainless steel structures,and the relevant research on the stainless steel shear wall is still blank.Existing studies have shown that stainless steel materials also have strong nonlinearity,high ductility,and excellent energy dissipation performance in addition to its excellent durability,which are very suitable for application to seismic energy dissipation components in building structures.Based on the above background,this dissertation focuses on the cross-stiffened stainless steel plate shear wall.Experimental research,numerical simulation and parametric analysis were carried out.The restoring force model and simplified design method of cross-stiffened stainless steel plate shear wall were proposed.The material mechanical properties tests of austenitic S30408 stainless steel,Q235 steel and low yield point steel under monotonic load were carried out.The stress-strain curves and various material mechanical properties were obtained,including the initial elastic modulus,nominal yield strength,ultimate tensile strength and elongation after fracture.The results showed that:（1）Stainless steel and low yield point steel have good ductility;（2）The two-stage material stress-strain curve proposed by Rasmussen fitted well with the stainless steel material property test curve.The material mechanical properties test of austenite S30408 stainless steel under cyclic load was carried out.The cyclic constitutive model of stainless steel was obtained.The test results showed that:austenitic S30408 stainless steel has good energy dissipation capacity,and its hysteretic behavior combines the characteristics of both isotropic strengthening and follow-up strengthening.Based on the material mechanical properties test,the low-cycle reversed load test of 8 steel plate shear walls were carried out by the four-bar loading device.The hysteresis curves,skeleton curves,ductility factor andζ-θcurves were obtained.The mechanical properties,energy dissipation characteristics and failure mechanism of steel plate shear walls were proposed.The results showed that:（1）During the loading process,each specimen has undergone the transition from elastic working state to elastoplastic energy dissipation state;（2）The stainless steel specimens have good ductility.The effective tension band of stainless steel specimens is formed after buckling,leading to good bearing capacity even if the displacement angle has exceeded 1/50;（3）The corners of the low yield point steel specimen and Q235 steel specimen were teared at the later stage of loading,resulting in the failure to form the reliable tensile band.The bearing capacity of the low yield point steel specimen and Q235 steel specimen decreased significantly at the later stage of loading,leading to the poor ductility;（4）Stainless steel specimens and low-yield-point steel specimens can enter the yield state earlier,therefore their energy consumption performance is better than ordinary steel specimens.The finite element analysis software ABAQUS was used to establish the accurate model of the steel plate shear wall.The numerical simulation analysis was performed to obtain the hysteresis curve,skeleton curve and equivalent viscous damping ratioζ-interlayer displacement angleθcurve of each specimen.Comparing the calculation results of the finite element with the test results,the accuracy of the finite element model is verified.The results showed that:（1）When the monotonic load material constitutive model is used for calculation,the skeleton curve is relatively close to the test result,but the equivalent viscous damping ratio is larger than the test result,and the hysteretic path also has a certain difference with the test result;（2）When the material constitutive model under cyclic load is used for calculation,the shape of hysteresis curve,hysteresis path and energy dissipation performance obtained by finite element analysis are closer to the test.Therefore,in the subsequent parametric analysis of hysteresis,the material constitutive model under cyclic load is used for numerical simulation.Based on the verified accurate model,a simplified finite element model of cross-stiffened stainless steel plate shear wall was established,and the parametric analysis of its elastic buckling performance were carried out.The influence of width-height ratioα,height-thickness ratioλ,edge stiffener rib stiffness ratioη_f and cross stiffener rib stiffness ratioη_s on the elastic buckling bearing capacity of steel plate wall were studied.The analysis results showed that:（1）The elastic buckling critical stressτ_cr decreases with the increase of the width-height ratioα,decreases with the increase of the height-thickness ratioλ,and increases with the increase of cross stiffener rib stiffness ratioη_s;（2）When the edge stiffener rib stiffness ratioη_f≤5,it has a great influence on the elastic buckling critical stressτ_cr,andτ_cr increases with the increase ofη_f;（3）When the edge stiffener rib stiffness ratioη_f≥5,its influence on the elastic buckling critical stressτ_cr is negligible;（4）Through further multi-parameter coupling parameterized analysis,a simplified calculation formula for the elastic buckling critical stressτ_cr of the cross-stiffened stainless steel plate shear wall with two sides connected is proposed.Meanwhile,based on the test results and the parametric analysis of the elastic buckling performance,the parametric analysis of the hysteretic performance of the cross-stiffened stainless steel plate shear wall were carried out.The effects of width-height ratioα,height-thickness ratioλ,edge stiffener rib stiffness ratioη_f and cross stiffener rib stiffness ratioη_s on the hysteretic performance of steel plate walls were investigated.The analysis results showed that:（1）With the increase of width-height ratioα,hysteresis pinch phenomenon is becoming more and more obvious,the energy dissipation capacity decreases and the bearing capacity of steel plate shear wall increases;（2）With the increase of height-thickness ratioλ,hysteresis pinch phenomenon is becoming more and more obvious,the energy dissipation capacity decreases and the bearing capacity of steel plate shear wall decreases.（3）When the edge stiffener rib stiffness ratioη_f<30,its influence on the hysteretic behavior of steel plate shear walls is very significant,and the bearing capacity and energy dissipation performance of steel plate shear walls increase with the increase ofη_f value;When the edge stiffener rib stiffness ratioη_f≥30,its influence on hysteretic behavior of steel plate shear walls is not significant.（4）When the cross stiffener rib stiffness ratioη_s<30,its influence on the hysteretic behavior of steel plate shear walls is very significant,and the bearing capacity and energy dissipation of steel plate shear walls increase with the increase ofη_s value;When the cross stiffener rib stiffness ratioη_s>30,its influence on the hysteretic behavior of steel plate shear walls is not significant.（5）The influence degree of height-thickness ratioλon the hysteretic behavior of steel plate shear wall is greater than that of width-height ratioαon the hysteretic behavior of steel plate shear wall.Based on the theoretical analysis,experimental research and parametric analysis of the cross-stiffened stainless steel plate shear wall were carried,the restoring force model of the cross-stiffened stainless steel plate shear wall was proposed.This model is a directional"Triple line"model,and the applicable range is:height-thickness ratio 100≤λ≤600,width-height ratio0.5≤α≤2.0,cross stiffener rib stiffness ratio 30≤η_s≤60,edge stiffener rib stiffness ratioη_f≥max{30,η_s}.The simplified model and simplified design method that are easy to be used in engineering design were also proposed.Comparing the calculation results of the SAP2000simplified model with the calculation results of the ABAQUS finite element shell model,the accuracy of the simplified model was verified.