Experimental Study On Seismic Behavior Of High-strength Manufactured Sand Concrete-filled Shear Walls With Ring Stirrups

The rapid development of high-rise and super high-rise buildings is depended on the development of the structural components that have high carrying capacity and excellent seismic performance and can increase using space as well.The shear wall has become the main anti-lateral force component of high-rise building structure due to its large lateral stiffness and strong bearing capacity,but the application of ordinary reinforced concrete shear walls are restrained by the height of the building.On the other hand,high-strength manufactured sand concrete has the characteristics of high brittleness and high strength,and it is difficult to use directly as structural force members.This research proposes a new type of combined shear wall that is the “high-strength manufactured sand concrete-filled shear walls with ring stirrups”.It can effectively improve defects of the brittleness of high-strength manufactured sand-concrete through compound constraint of ring-stirrups and steel tubes,which can bring into full play to its strength advantage.At the same time,placing the steel tubes at the end of the new combined shear wall and setting ring stirrups in the full section to improve its seismic performance.Seismic behaviors of the high-strength manufactured sand concrete-filled shear walls with ring stirrups have been studied in this paper.The studying is about the aspects of the hysteresis curve,skeleton curve,bearing capacity,deformation capacity,stiffness and strength degradation,and energy consumption.Introducing the stiffness degradation indicators for performance evaluation as well.The main research contents are as follows:(1)Four high-strength manufactured sand concrete-filled shear walls with ring stirrups with shear-to-span ratio of 2.125 are designed according to the variation parameters of axial compression ratio,steel content and volume hoop ratio.The quasistatic test is performed.The apparent morphological evolution of the new composite shear wall specimens under low cyclic loading is observed.Emphatically observing the development of cracks.The failure mechanism is studied.(2)The hysteresis curve and skeleton curve characteristics of the high-strength manufactured sand concrete-filled shear walls with ring stirrups are studied.The effects of axial compression ratio,volumetric hoop ratio and steel content on the seismic performance of the bearing capacity,deformation capacity,stiffness degradation and strength degradation of the members are analyzed,and the key influence parameters are obtained.(3)With reference to the norm and the calculation formula of the bearing capacity proposed by the relevant scholars,the bearing capacity of the high-strength manufactured sand concrete-filled shear walls with ring stirrups are calculated by the two different methods.The calculated values compare with the experimental values to check the applicability of the formula.In addition,a formula for the pressure distribution of the combined shear wall axis is proposed,and the reliability is verified by comparing the calculated value with the experimental value.(4)The performance level of the high-strength manufactured sand concrete-filled shear walls with ring stirrups are divided,and the criteria for the four-level performance level of basic intact,minor damage,medium damage and severe damage are defined.The stiffness degradation index is used to calculate the index values of different performance levels,and the influence of different parameters on the index values is analyzed.On this basis,the threshold value of the performance level of the new combined shear wall is suggested.