火灾后钢筋混凝土柱剩余承载力研究

进行了3个IS0834标准火灾作用后钢筋混凝土柱力学性能试验和3个常温下的对比试验，考察火灾作用对钢筋混凝土轴心受压柱和偏心受压柱破坏形态、变形特点及剩余承载力的影响．试验结果表明：火灾后钢筋混凝土柱在荷载作用下的破坏形态和常温下基本相同：在混凝土强度和升温条件相同的情况下，随着偏心率的增加，试件的承载力降低；火灾后偏压柱的截面应变分布基本符合平截面假定，但试件的抗弯刚度和极限承载力显著降低，经历90min的火灾作用后，试件的剩余承载力大约只有常温下极限承载力的25％～37％．

Experimental Study on Residual Load Bearing Capacity of Reinforced Concrete Columns after Exposure to Fire

By tests on three reinforced concrete columns after exposure to ISO834 standard fire and three other columns at room temperature without exposure to fire. The mechanical properties of reinforced concrete columns after exposure to fire are experimentally studied. Test results show that the failure mode of reinforced concrete columns after exposure to fire is basically the same with that at room temperature. With the same concrete strength and heating condition, the load bearing capacity of specimens reduces as the eccentricity increases. Strain along the section height of eccentric columns after exposure to fire is basically in agreement with the plane section assumption, while the flexural rigidity and ultimate load bearing capacity of that decrease notably. The residual load bearing capacity of reinforced concrete columns after exposure to ISO834 standard fire for about 90 minutes is only about 25% to 37% of that at room temperature.