Parametric Studies on Restrained Steel Column in Fire (Ⅰ)：Under Axial Load Only

Abstract:

This paper investigates behaviors of the restrained column under axial load in fire through using a calibrated finite element method model.Presented results include the column axial force-temperature evolution curve,column bending moment-temperature evolution curve,failure temperature of restrained column,difference between failure temperature of unrestrained and restrainedcolumn,and difference between failure and bucklingtemperature of restrained column.Results of parametric study show that:①before the column buckles,the axial force in column increases linearly and bending moment only varies a little;②after the column buckles,the bending moment in column increase suddenly,and the column is loaded under combined axial force and bending moment;③the axial restraint reduces failure temperature of restrained column;and the reduction in failure temperature increases with increasing of axial restraint stiffness.However,there is a critical restraint stiffness ratio,above which no further reduction in column failure temperature occurs.