钢管混凝土柱火灾后剩余承载力的试验研究

通过对6个圆形截面和6个方形截面钢管混凝土柱按ISO-834和GB9978-88规定的标准升温曲线升温作用后承载力的试验研究,研究钢管混凝土柱在标准升温曲线作用后力学性能和剩余承载力的变化规律。考察了构件长细比和荷载偏心率等因素对承载力损失率的影响。研究结果表明:在本次试验参数范围内,火灾后裸钢管混凝土柱的承载力损失严重,带护保护层的构件次之。在其它条件相同的情况下,与常温下的承载力相比,长细比越大,构件火灾后承载力的损失率越高。荷载偏心率则对火灾后构件承载力的损失率影响不大。本文的研究成果可为有关钢管混凝土工程进行火灾后修复加固时提供参考。

TESTS ON THE RESIDUAL STRENGTH OF CONCRETE FILLED STEEL TUBULAR COLUMNS AFTER EXPOSURE TO FIRE

The behavior of concrete filled steel tubular columns subjected to axial or eccentric loads was experimentally investigated. Both protected and unprotected concrete filled steel tubular columns were tested and the results are presented in this paper. The fire attacks in the test are those prescribed in the ISO-834 and the China National Standard GB-9978. The tested specimens included six circular columns and six square columns. It was found that the loss of the strength of unprotected specimens is significantly greater than that of protected columns. The slenderness ratio has a significant influence on the strength loss ratio, and large loss of strength is expected for specimens with large slenderness ratios. It was also observed that the load eccentricity ratio has little influence on the strength loss ratio. The results in this paper may serve as a reference for practical design.