Experimental Research And Numerical Simulation On Seismic Behavior Of Cold-Formed-Steel-Framed Shear Walls Sprayed With Lightweight Mortar

The cold-formed-steel-framed structure sprayed with lightweight mortar is in line with the current new rural construction and urbanization in China.It not only has the advantages such as light weight,earthquake resistance,low-carbon environmental protection of the traditional light steel house with hanging plates at two sides,but also improves the structural performances such as thermal and sound insulation,fireproofing,lifting force and shock resistance,and upgrades the carrying capacity of the cold-formed thin-wall steel member and the structural performance of whole bearing horizontal force.In this paper,in order to research the seismic behavior of the cold-formed-steel-framed shear walls sprayed with lightweight mortar,through four full-scale tests under low reversed cyclic loading,the failure process and pattern were observed and recorded,the experimental results of hysteresis curves and envelope curves were obtained,and the detailed discussions on hysteretic loops,shear capacity and energy absorption were given.The results show that: the failure mode of the cold-formed-steel-framed shear walls sprayed with lightweight mortar mainly is compression buckling of end studs;Compared with cold-formed thin-wall steel framed walls with sprayed lightweight mortar on both sides,the walls with sprayed lightweight mortar on the face and calcium silicate board on the back has a relatively lower load bearing capacity and stiffness.Simulate the shear behavior of the tests with ANSYS,the calculated results agreed well with the test results.On this basis,the parameter analysis about the aspect ratio of walls,the yield strength of steel,the thickness of studs and the axial compression ratio of studs on the shear behavior of shear walls was carried.The analysis results indicate that the changes of yield strength and thickness of end studs had a great effect on the shear behavior of tests.There is an effective binding action between the steel framing and light mortar,and its integrity is stronger then the connection between all types of plates and steel skeleton by self-tapping screws;The aspect ratio of walls and the axial compression ratio of studs should also be considered in the process of structural design.In this paper,the stiffness variation laws of feature points of hysteresis curves were summed according to the results of tests.Then,based on the Richard-Abbott curve,the sectional nonlinear hysteretic model were established to similate the seismic behavior of the cold-formed-steel-framed shear walls sprayed with lightweight mortar,and model parameters of specimens were estimated by Origin software.This sectional nonlinear hysteretic model,which agreed well with the hysteretic loops of test specimens,could provide the theoretical basic for the time history analysis of the cold-formed-steel-framed shear walls sprayed with lightweight mortar.