Fire resistance of thin-walled steel tube confined reinforced concrete middle-length columns: Test and numerical simulation

Abstract

Steel tube confined reinforced concrete (STCRC) column is a new type of composite compressive member. In recent years, the structural performance of the STCRC columns has been widely studied to promote its application, and this paper presents experimental and numerical studies on the fire-resistance behaviour of the middle-length members. Parameters, including thickness of steel tube, loading mode (axial or eccentric), and load ratio, were considered in the tests. Moreover, the furnace temperature, column temperature, axial displacement, lateral displacement, and applied load were recorded during the tests, and the failure pattern was obtained after the tests. The finite element model (FEM) was developed by ABAQUS and validated against the test results. Through parametric analyses, the effects from eccentric ratio, load ratio, cross-section diameter, material strength, the thickness of steel tube, and reinforcement ratio on the fire resistance of the middle-length STCRC columns were further studied. It was found that increasing the section diameter, concrete strength, yield strength of reinforcement, and reinforcement ratio would enhance the fire resistance of the columns. However, increasing eccentricity, yield strength of steel tube, thickness of steel tube, and load ratio would reduce the fire resistance of the columns.