Mechanical Behavior And Catenary Action Of Restrained Steel Beam Under Fire

To investigate the mechanical behavior and catenary action of restrained steel beam under fire, experiments were performed on five H-section restrained steel beams exposed to ISO-834 standard fire. At first, mechanical property tensile tests were performed on 3 room-temperature specimens and 8 high-temperature specimens, and variation laws of the material properties of steel materials with temperature rising were investigated by the high-temperature steady-state tests. Through the fire experiments, the temperature data, mid-span deflections and failure modes of all specimens were obtained. The experimental results show that: (1) a restrained steel beam is prone to in-plane buckling failure under fire; (2) the loading ratio n and axial restraint stiffness Kx have great influences on the catenary action of restrained steel beam under fire; (3) when the loading ratio n is constant, the greater the axial restraint stiffness Kx, the later the catenary action occurs; when the axial restraint stiffness Kx is constant, the greater the loading ratio n, the earlier the catenary action occurs. Copyright (C) 2021 by The Hong Kong Institute of Steel Construction. All rights reserved.