IMPACT PERFORMANCE AND THE INFLUENCE FACTORS OF REINFORCED CONCRETE SLABS UNDER HIGH TEMPERATURES

When reinforced concrete (RC) structures are subjected to fire, they are often exposed to the secondary impact due to the fire-induced floor collapse, resulting in the coupling effect of high temperature and impact loading on RC slabs. This study examines the impact performance of RC slabs under high temperature considering the thermal mechanical coupling effect at elevated temperature and the strain rate effect under impact load. The established numerical model is validated by comparing the test results of fire resistance and impact resistance of RC slabs with the corresponding simulated results. The dynamic responses of RC slabs under different fire duration and different impact energy are obtained, and the influence of slab thickness and reinforcement ratio on the impact resistance of RC slabs under elevated temperatures is discussed. The results show that the high temperature caused by fire can significantly affect the impact resistance of RC slabs. The punching shear damage of RC slabs becomes severe with the increase of fire duration, and the mid-span peak displacement grows as well. The increase of slab thickness can significantly improve the impact performance of RC slabs under high temperature, while the rise of reinforcement ratio shows limited effect.