Fire resistance of axially restrained Q690 H-shaped welded steel columns: Test, simulation and design

Abstract

Six fire resistance tests of axially restrained Q690 high strength steel (HSS) columns were conducted in this paper to obtain its fire response and failure pattern. Slenderness, axially restraining stiffness, and load ratios were considered in the tests. The furnace temperature, specimen temperature, specimen deformation, and internal force were recorded during the tests. Furthermore, the critical temperature, fire resistance, failure pattern, and post-buckling behavior were determined based on the test results. Test results showed that increasing the load ratio, axial restraining stiffness ratio, and slenderness would reduce the critical temperature of the specimens. After that, numerical models incorporating residual stress and non-uniform temperature field were developed and calibrated with the test results. Finally, parametric analyses were performed, and a simplified design method was proposed to evaluate the critical temperature of restrained Q690 HSS columns.