Experimental Study On Seismic Behavior Of T Section Concrete Short Pier Shear Wall With High-strength Steel Bars

Short-leg shear wall structure system has good service performance,but its seismic performance is relatively poor,so its application in earthquake area is strictly limited.How to improve the seismic performance of short-leg shear wall structure system and make full use of the favorable characteristics of short-leg shear wall is an important task for design researchers,and is also the basis for the application and promotion of the structure system.In this paper,six T-section short-leg shear wall members with high-strength steel bars were tested under low-cycle cyclic loading,and some seismic characteristics of high-strength steel short-leg shear wall members were obtained by comparing with the results of the research group.The energy dissipation performance,peak load and ductility of these high-strength steel short-leg shear wall members are compared and analyzed.At the same time,the failure modes of the members are recorded and analyzed in detail,and the effects of the mechanical parameters and material factors on the seismic performance are compared and analyzed.The main contents and conclusions are as follows:1.By comparing the hysteretic curves and skeleton curves of the test group,we can see that the energy dissipation capacity and ultimate load of the short-leg shear wall members with high-strength steel bars in this batch have been significantly improved.However,compared with the original control test,the ductility of the components in this batch has decreased,because the original control test used # 4 ultra-high strength stirrups.This shows that the mechanical properties of stirrups have a great influence on the ductility of members,and the strength of longitudinal bars has a direct impact on the ultimate load and energy dissipation capacity of members.This indicates that the high strength steel bars belong to the rigid anti-seismic scheme.2.the quality of concrete at the bottom of the slab has great influence on the energy dissipation performance and the positive ultimate load of the component.Therefore,in order to ensure the seismic performance of short-leg shear wall members,great attention should be paid to the strength and quality of web(especially the end)concrete.3.With the increase of axial compression ratio,the ductility of components decreases,but the ultimate load increases.When the section thickness ratio is small and the axial compression ratio itself is not too large,the influence of longitudinal reinforcement ratio on ductility is greater than that of axial compression ratio.4.With the increase of the height thickness ratio,the positive and negative peak load increases significantly.When the section thickness is relatively small(< 6.5),the reverse peak load is obviously greater than the forward corresponding value.When the height-thickness ratio of the cross-section is close to 6.5,the positive and negative peak loads are close,and the members can achieve better energy dissipation performance and ductility.When the section thickness is large(> 6.5),the forward peak load is obviously larger than the reverse value.5.The failure of short-leg shear wall members begins at the end of web,and there may be no obvious phenomenon of flange plate at the end of failure,but the failure characteristics of web are always very obvious.The failure modes on the sides of the T section members have good symmetry.Furthermore,it can be found from the strain evolution diagram that the T-section short-leg shear wall members can well conform to the plane section assumption during the failure process.6.The crack distribution pattern of short-leg shear wall members has a certain regularity.Vertical short cracks and oblique cracks are dominant at the end of web and observation surface respectively,while vertical or horizontal cracks are dominant at the outer flange plate.7.Hoop reinforcement slightly improves ductility of members,but has no significant effect on ultimate bearing capacity and energy dissipation capacity of members.Moreover,hoop reinforcement has no obvious effect on the relative time of delaying the occurrence of the first web crack.It may be more obvious that a smaller spacing of dense spiral hoop or section steel is arranged at the end of the web.Contrast effect.