Nonlinear Fem Analysis On Cold-formed Steel Concrete Composite Shear Walls

Shear walls are widely used in multi-layer buildings and high-rise buildings of reinforced concrete structures which are major lateral force resisting structural members.Ground floor shear walls of high-rise buildings suffers greater axial force and seismic force,their ductility is poor,especially I-shaped shear walls,which become the weak part of the seismic system for their poor seismic performance.It is necessary to study constructional measures of shear walls to improve their seismic performance,such as shear walls with embedded cold-formed steel framework,etc.Though current research on cold-formed steel concrete composite shear walls has made some achievements,it is still lack of systematic analysis on them.Therefore,study on axial load ratio,shear span ratio and different forms of cold-formed steel frameworks' impact on the shear walls'forced performance is conducted systematically.The paper first analyzes the current situation of the study on composite shear walls with embedded cold-formed steel and lay a good foundation for conduct the study on the topic.Based on shear wall structures of this type and their mechanical characteristics,nonlinear FEA calculation models are created.In order to analyze the impact of the relative slippage between the cold-formed steel embedded and concrete shear wall on forced performance of composite shear wall,the nonlinear FEA models of shear wall specimens considering bond-slip and not considering bond-slip are created.The result shows that the results considering the slippage and not considering the slippage are similar and they agree with the experiment result by nonlinear FEA calculating.So there is a good bonding property between steel and concrete,the impact of bond and slip on the forced performance of shear walls can be ignored.In order to systematically analyze the forced performance of concrete shear walls with embedded cold-formed steel,the paper also analyzes shear wall structure embedded with cold-formed steel frames of three different forms with nonlinear FEA.The result indicates that the stiffness,ductility,carrying capacity of composite shear walls with embedded steel forms which has braces is higher than others.Therefore,braces are necessary.has braces is higher than others.Therefore,braces are necessary.The paper also analyzes the axial compression ratio,shear span ratio and other parameters'impact on the performance of shear walls with the variety of parameters,concludes the disciplines of the parameters' impact,and lay a necessary foundation for the promotion and application of shear walls.