Experimental Study On Steel Lap Connection And Seismic Performance Of Prefabricated Concrete Shear Wall Based On Thin-Wall Steel Pipe

For prefabricated shear wall structures,the connection mode and seismic performance of the nodes are important factors to determine whether they can be popularized.The connection mode at the node position of the component should not only ensure the stable transfer of force between the upper and lower layers of the structure,but also require simple,convenient and quick construction during field installation.which is the decisive factor for the practical application of the shear wall structure system developed.Therefore,the project team proposed a prefabricated concrete shear wall structure system based on thin-wall steel pipe,which has the characteristics of convenient transportation and hoisting,simple site construction and good structural integrity.In order to study the mechanical properties of the shear wall structure,two types of specimens were designed and made to study the joint connection mode at the horizontal joint position and the seismic performance of the wall.(1)An indirect lap connection method of thin-wall steel pipe and steel bar is proposed.During field installation,the wall is hoisted and the positioning steel bar of the lower layer passes through the steel pipe hole set inside the wall,and then the connection between the upper and lower layers is realized by pouring concrete into the steel pipe hole.Two groups of lap joints were designed and made to study and determine the reliability and design principle of this kind of lap joints.The test results show that the failure mode of the two groups of specimens is the slip between the perforated concrete and the thin-walled steel pipe,and the connecting steel bar does not yield.The anchoring length of the connecting steel bar can not be determined according to the design specification of concrete structure.Based on the analysis of the test results,the actual lap length of the steel bar required by the specimen is deduced by theoretical calculation.At the same time,two schemes are proposed to improve the lap performance of the specimen,one is to increase the lap length of the connecting steel bar,and the other is to improve the bond strength between the perforated concrete and the thin-walled steel pipe.(2)One cast-in-place ordinary reinforced concrete shear wall specimen and two prefabricated concrete shear wall specimens based on thin-wall steel tubes were designed and manufactured.The failure modes and seismic performance indexes of the walls were studied.The test results show that the failure mode of thin-wall steel tubular shear wall specimens is the same as that of cast-in-place shear wall specimens,and the change law of hysteretic characteristic curve.The failure mechanism of two thin-walled steel tubular shear walls with different connection forms of vertically distributed steel bars is the same,and there is little difference in various seismic performance indexes.Reducing the vertical connection has little influence on the seismic performance of thin-walled steel tubular shear wall specimens.(3)The finite element analysis software ABAQUS was used to establish the mathematical model of the wall specimen for analysis,and the results of the numerical analysis were compared with the test results.The results of numerical analysis are in good agreement with the experimental results.