Research on the Residual Bearing Capacity of Square Hollow Concrete-filled Steel Tube After Fire

Abstract

In order to study the change of the residual bearing capacity of square hollow concrete-filled steel tube after fire, the finite element analysis software ABAQUS was used to establish the finite element model of square hollow concrete-filled steel tube under the ISO-834 standard fire heating condition, and the temperature distribution and deformation of the model were simulated and analyzed. Based on that, the influence of parameters such as the strength grade of concrete, the strength grade of steel, the calculated length of member and the hollow ratio of section on the residual bearing capacity of member after fire is simulated and analyzed. The results show that the temperature distribution of the component is mainly affected by the section size, concrete strength grade and steel yield strength, but is less affected by the calculated length. The temperature of the inner concrete and the inner steel tube decreases with the increase of the thickness of the member. The strength of steel and the size of section have more influence on the stress characteristics of the member after fire, but the strength grade of concrete and the length of the member have less influence. Among them, the increase of steel strength, concrete strength will enhance the fire-resistant limits of components. When the hollow ratio of the section increases, the fire resistance limit of the component increases first and then decreases. The increase of the calculated length will reduce the fire resistance limit of the member. The residual bearing capacity of the component decreases with the increase of fire time.