Research On Axial Behavior Of Innovative Composite Shear Wall With Steel Tubes And High-Strength Concrete

The current demand for urban constructing high-rise buildings and national nuclear power facilities is increasing further enhancing the seismic performance of buildings.As the main lateral force-resisting elements of building cores,shear walls have the advantages of high integrity,high lateral stiffness,flexible and diverse arrangement and can avoid the protrusion and exposure of beams and columns.However,traditional reinforced concrete(RC)composite shear walls also have some weaknesses,such as lower bearing capacity,poorer seismic capacity,complex structural design and calculation,and difficult for construction.In order to improve the performance of RC shear walls,a new type of innovative composite shear walls with steel tubes and high-strength concrete(ICSW)is proposed in this paper,in which wide flange H-beam,C-beam or channel,rectangular steel pipe are spliced into multi-partition steel tubes and high-strength concrete is casted in each partition.ICSW can give full play to the performance of both steel and concrete and improve the ductility of the component.However,the research on ICSW at home and abroad is still in the initial stage,and systematic research is lacked.Therefore,in this paper,the basic axial compression performance of ICSW is investigated as follows:(1)A total of seven specimens were designed to conduct push-out test,considering Width-thickness ratio and lateral confinement.The load-slip curves of the specimens were investigated and analyzed the composition of the interfacial bonding force of steel tubes.Finally,a constitutive model between multi-partition steel tubes and concrete was proposed.(2)An axial compression test was carried out on twelve on normal concrete and recycled aggregate concrete inside multi-partition steel tubes.The effect law of the confinement factor on the axial strength of concrete can be clarified and the calculation method of the axial compression mechanical properties of core concrete under the parallel connection of multi-partition steel tubes by observing the damage process of the specimens and analyzing the load displacement curve of concrete,respectively.(3)Three low ICSW were tested under axial compression to observe the damage modes,compare the axial load-displacement curves of the specimens and analyze how axial bearing capacity,stiffness performance and ductility performance were affected under different parameters such as height and aspect ratio.Finite element analysis of the specimens were subjected to analyze the mechanical behaviors of distribution law of the cross-sectional stress and the confinement effect of steel to the inner concrete.The variation law of the axial performance of the specimens under different parameters was evaluated and the method of calculating the vertical bearing capacity of the specimen was proposed,respectively.(4)The axial compression test study and finite element analysis of three high ICSW were carried out to observe the global failure model as well as local failure model of the specimen.