Fire-resistance performance of simply supported fire-resistant steel-concrete composite beams

Abstract:

To study the fire performances of the simply supported fire-resistant steel-concrete composite beams (FRSCCB), the simply supported FRSCCB with fireproof coating and fire-proof board under standard fire were simulated by the finite element (FE) software ABAQUS. The effects of the load-ratio, the fire-insulation of the steel beam, the strength of materials, the section profiles and the diameter of longitudinal rebars in the concrete slab on the fire performance of the simply supported FRSCCB were analyzed. It is shown that the two most important factors, which influence the fire resistance for the simply supported FRSCCB, are the load-ratio and the fire-insulation thickness of the steel beam. The thicknesses of the beam plates and the width of the beam flange have favorable effect on the FRSCCB performance, but the strength of materials, the height of the beam, the thickness of the slab and diameter of the rebars have less influence. The fire-proof board has better fire-proof protection effect than the fire-proof coating under the same condition. When load ratio is 0.5~0.7, the fire-resistance limitation is increased by over 35% and the fire-insulation thickness can be decrease by 30% when the FRSCCB is used. The simplified calculation method for predicting the fire resistance limit according to Chinese code (CECS 200:2006) is conservative compared with the FE results when the load-ratio is small.