火灾下双钢板-混凝土组合墙抗冲击机理分析与挠度预测OACSTPCD

Steel-concrete composite wall(SC wall)has been widely employed as the main structural components in nuclear power plants and high-rise buildings.Its performance under accidental loads is a key index for its utilization.In this paper,the mechanical behaviors of SC walls under coupled fire and impact loads are investigated and corresponding design recommendations are given.Firstly,a finite element(FE)model of SC walls under combined fire and impact loads is developed.After validating the FE model,the response mechanism of SC walls under combined fire and impact loads is analyzed.Afterwards,effects of axial force,fire duration,material strength,impact energy and type of shear connectors on the impact resistance performance of components under fire condition are studied.Finally,simplified formula for predicting the maximum mid-span deflection under coupled fire and impact loadings is proposed.In view of the failure pattern,the outer steel plate on the surface exposed to fire presents wavy buckling.With the increase of fire duration,the deformation mode of SC walls changes from local punching deformation to overall flexural deformation.Under combined fire and impact loads,concrete is observed to be the main energy consumption component within the SC walls.The peak membrane force and the maximum mid-span deflection are employed to analyze the impact resistance of the SC walls.Test results show that the fire duration has a significant effect on the impact resistance.The peak membrane force of the SC walls reduces by approximately 36％under 90 min fire duration,while the maximum mid-span deflection increases by 50％.The concrete strength,axial force and type of shear connectors also obviously affect the impact resistance of the SC walls,while the influence of the yield strength of steel plate is moderate.The proposed formula can reasonably predict the maximum deflection of the SC walls under combined fire and impact loads.