Numerical Simulation On Seismic Performance Of Concrete-Filled Steel Tube Confined Superimposed Slab Shear Walls

As the main part of the structural lateral resistance in high-rise buildings,shear walls are attracted by the academic circles to study its seismic performance continuously.This paper presented a composite shear wall with concrete-filled steel tube edges.The steel tube was filled with concrete as the edge restraint member,and between the edge restraint members were prefabricated superimposed slab shear walls,which relied on shear connectors to increase the integr ity of the shear wall.The steel tube filled with concrete can greatly enhance the bearing capacity,and the superimposed slab shear wall can be prefabricated in advance in the factory,reducing the wet operation on site and shortening the construction period.In this paper,a numerical analysis model for concrete-filled steel tube confined superimposed slab shear walls was proposed using OpenSees software.According to the existing tests,the proposed analysis model was validated.The high degree of fitting between the numerical analysis results and the experimental results indicated that the proposed numerical analysis model had good rationality and accuracy.Using the proposed numerical analysis model,the shear wall forms designed in this subject were numerically simulated and analyzed.The influences of axial compression ratio(0.3～0.6),section forms,concrete strength,steel tube strength,steel tube thickness and cross-section steel ratio on the seismic performance of shear walls were emphatically studied.A method for calculating the bearing capacity of the shear walls was proposed.The results showed that the increasing of axial compression ratio,the strengthening of concrete and steel tube,the increase of steel tube thickness and steel ratio all increased the bearing capacity of shear walls in different degrees.The increase of axial compression ratio would accelerate the damage behavior of concrete and the overall strength degradation.The increase of steel strength and section steel ratio increased the energy dissipation capacity.The thicker steel tube wall showed more full hysteretic behavior.Increasing the steel tube thickness could improve the strength of confined concrete and restrain the strength degradation of concrete at the same time.Steel bracing,cast-in-situ concrete superimposed slab shear walls and concrete-filled steel tube confined superimposed slab shear walls were placed in a typical three-story steel frame to form three diferent frame systems.20 ground motion records under the baseline design earthquake were selected and applied to each frame system one by one.The inter-story displacement angles of the first and top floors and the time-history responses of displacement under selected seismic waves were analyzed emphatically.The results showed that the proposed concrete-filled steel tube confined superimposed slab shear walls could exert better deformation control effect and exhibit excellent seismic performance.