Abstract:

A full-process analytical program for the simply-supported normal-strength concrete (NSC) and high-strength concrete (HSC) beams subjected to high temperature is proposed, in which the explosive spalling of HSC is approximately taken into consideration. The reliability of the program is validated by the test results provided by former researchers. Then, the effects of the main parameters on the fire resistance of simply-supported NSC and HSC beams are investigated and compared, by selecting 288 simply-supported beams with different load ratios, thicknesses of concrete cover, span-depth ratios and reinforcement ratios for the high-temperature response analy-sis. Based on the simulation results, simplified ways to quantificationally determine the fire resistance of simply-supported NSC and HSC beams are presented. The results show that the explosive spalling at a high temperature significantly influences the fire resistance of simply-supported HSC beams, and that the fire resistance of both HSC beams and NSC beams can be effectively improved by strictly controlling the load ratio and properly increasing the thicknessof concrete cover.

Key words: normal-strength concrete, high-strength concrete, simply-supported beam, high temperature, fire re-sistance, explosive spalling