火灾后混凝土连续构件的损伤与加固试验研究

为了研究受火后混凝土连续受弯构件的力学性能,进行了5个混凝土两跨连续板和7个两跨连续梁的系列试验.试验内容包括依据ISO 834标准升温曲线进行的混凝土连续构件受火试验,以及高温后受损构件和修复加固构件的静载试验.试验结果表明,高温对混凝土连续受弯构件的力学性能有明显的影响;随着受火程度的加重,混凝土构件力学性能呈下降趋势.分析试验结果可知,初始刚度降幅最为明显,正常使用承载力的降幅大于极限承载力的降幅;连续板试件的损伤大于连续梁试件.通过置换受损混凝土并采用碳纤维布加固受火后连续构件可使其承载力恢复到甚至超过受火前的状态,加固后初始刚度的提高并不明显.

Experimental Study on Damage and Rehabilitation of Reimforced Concrete Continuous Member After Fire

To study the mechanical performance of reinforced concrete continuous bending members after fire, a series of tests were carried out on 5 RC continuous slabs and 7 RC continuous beams, which included fire test on continuous members with the calefaction way of ISO834 and static test at ambient temperature on the fire damaged members and strengthened after fired members. The results demonstrate that high temperature has a obvious effect on mechanical properties of continuous bending member and along with an aggravated fire level, the mechanical properties showed decreasing trend. Based on the experimental data, the initial bending rigidity has the greatest reduction, the serviceability bearing capacity drops more than ultimate bearing capacity and the fire damage of continuous slabs is severe than that of continuous beams. Damaged concrete replacement and reinforcement with CFRP sheet can offset the loss of bearing capacity and even make it better than unfired state but has little effect on increasing the initial rigidity.