Experimental Study On Seismic Behavior Of Steel Tube Bundle-Concrete Composite Shear Wall With Stiffeners On Both Sides Of Steel Tube

The steel tube bundle-concrete composite shear wall,a new type of steel-concrete combined shear wall structure system,which has the advantages of assembly construction and flexible arrangement and adapt to the development of national industrial policy prefabricated building structures,it has been widely used in engineering,and access to significant social and economic benefits.Some studies have shown that under the reciprocating force of the steel tube bundle composite shear wall,local damage occurs on both sides of the bottom of the wall.Its failure characteristics are usually effective bond failure between steel and concrete,bottom steel plate buckling,concrete crushing,and reduced bearing capacity and ductility of components.In this paper,the failure mode of the root buckling of the end steel tube bundle is studied.Based on the concrete-filled steel tube column with stiffeners,a strengthening method with long stiffeners built into the steel tube bundles on both sides is proposed,and this reinforcement method can improve the buckling resistance of the steel tube bundles on both sides,thereby improving the seismic performance of the shear wall.(1)The quasi-static test is carried out on 2 pieces of ordinary steel tube bundle combined shear walls and 4 pieces of end steel tube bundles with stiffening rib steel tube bundle combined shear walls.Study the seismic performance of steel tube bundle shear walls with stiffeners at the end of the steel tube bundle,explore the principle of setting stiffeners in the tube wall of the end steel tube bundle to improve the buckling performance of the steel plate of the shear wall,analyze the effect of shear span ratio and axial compression ratio on stiffening ribs to improve the seismic performance of shear walls.The test result shows that the built-in stiffeners of the steel tube bundles on both sides can effectively improve the yield resistance of the steel tube bundles at the end of the wall,delay the buckling failure of the bottom of the shear wall,and improve the bearing capacity and ductility.When the shear span of the shear wall is relatively small,the shear deformation is dominant,and the effect of the stiffener is not obvious at this time.When the shear-span ratio of the shear wall increases,the transition from shear failure to bending failure will increase the bending deformation ratio of the wall.At this time,the effect of stiffening ribs on the internal concrete of the steel tube bundle is more obvious.After increasing the axial compression,the lateral deformation of the internal concrete increases,which makes the restraint effect of the steel tube bundle on the concrete stronger,and the effect of stiffening ribs to improve the shear wall is more significant.(2)On the basis of experimental research,combined with finite element numerical simulation,selecting appropriate constitutive relations,meshing and contact relations,the finite element analysis of the steel tube bundle shear wall with stiffening ribs at the end of the steel tube tie is carried out.Study the effects of shear span ratio,axial compression ratio,steel strength and steel plate thickness on its seismic performance.Simulation analysis shows that under the condition of larger shear-span ratio and axial compression ratio,the wall will fail in bending and compression,and the stiffeners can increase the buckling resistance of the steel pipe,thereby improving the wall performance more significantly.Increasing the strength and thickness of the steel plate is conducive to improving the elastic stiffness and peak bearing capacity of the shear wall,and has a significant impact on the seismic performance of this type of shear wall.