Research On Mechanical Performance Of Cold-Formed Steel-Concrete Shear Wall

Cold-formed steel-concrete shear wall is a new type of composite shear wall formed by a cold-formed steel framework wrapped with steel membrane mesh and filled with ordinary concrete.Compared with the existing light steel-lightweight concrete composite shear wall,the cold-formed steel-concrete shear wall has the advantages of large bearing capacity and strong seismic performance,thus can be used as the main force-bearing member in the high-rise building structure system.This paper studies the seismic performance of cold-formed steel-concrete shear walls.The specific work is as follows:(1)Based on ABAQUS finite element analysis software,the fine finite element model of cold-formed steel-concrete shear wall under low reversed cycle loading is established.The parameters,such as concrete constitutive model,steel material constitutive model,member size,element type,structural reinforcement,boundary condition,cold-formed thin-walled steel structure form and spacing used in the establishment of the finite element model,are detailedly introduced.(2)Based on the results of the finite element analysis on the cold-formed steel-concrete shear wall,the stress mechanism of the cold-formed steel-concrete shear wall was studied in depth,and the change low of failure mode and the stress transfer mechanism of the wall at different stages were determined.The change law of the transmission mechanism.In addition,the influence of parameters such as concrete strength,steel bar spacing,steel bar structural shape,and shear span ratio on the mechanical properties of the wall is studied.The results show that:improving the concrete strength level and using triangular punched steel can significantly enhance the bearing capacity and lateral stiffness of cold-formed steel-concrete shear walls,but the size of the steel bar spacing has little effect on it;and increasing the shear span ratio is detrimental to the ultimate bearing capacity of the wall.(3)Based on the above analysis of the force-transfer mechanism and stress-transfer path of the cold-formed steel-concrete shear wall,a softened strut-and-tie model for calculating the bearing capacity of the cold-formed steel-concrete shear wall is established.The calculated value of the model is in good agreement with the test results and the numerical analysis results.(4)Based on the above-mentioned softened tension-compression model of cold-formed steel-concrete shear wall,the calculation formula of shear bearing capacity of cold-formed steel-concrete shear wall is established by using force balance theory;According to the analysis,the formula for calculating the shear capacity of the inclined section of a cold-formed steel-concrete shear wall with a standardized form is suggested.The above calculation results are in good agreement with the test results and numerical analysis results.