火灾后型钢混凝土柱加固试验研究

EXPERIMENTAL STUDY ON REHABILITATION OF SRC COLUMNS AFTER EXPOSURE TO FIRE

通过火灾后碳纤维布和外包角钢加固型钢混凝土柱的静力加载试验及常温与火灾后未加固试件的对比试验,研究了碳纤维布和外包角钢加固对火灾后型钢混凝土柱承载力与刚度的修复效果。试验结果表明:火灾后经碳纤维布和外包角钢加固后,型钢混凝土柱破坏时变形发展更充分、延性更好。碳纤维布加固,能在一定程度上提高火灾后型钢混凝土柱的承载力,但对火灾后型钢混凝土柱刚度的修复效果不明显。外包钢加固对火灾后型钢混凝土柱承载力的修复效果比碳纤维布加固更加显著,能将火灾后型钢混凝土柱的承载力修复至常温未受火以前的水平,但外包钢加固也仅对火灾后长细比较大的试件的刚度有一定的提高作用,对长细比较小的试件的刚度修复效果不明显。

By tests on some SRC （steel reinforced concrete） columns strengthened with CFRP （Carbon Fiber Reinforced Polymer） and external steel clad after exposure to fire and some other comparable SRC columns without being strengthened after exposure to fire as well as at normal room temperature without exposure to fire, the rehabilitating effect of fire-damaged SRC columns are experimentally studied. Test results show that because of the confinement effect of CFRP and external steel clad, the failure process and distortion development of SRC columns after exposure to fire are more adequate when strengthened with CFRP and external steel clad, and the ductility of those columns are better than that without being strengthened. The load-bearing capacity of fire-damaged SRC columns can be enhanced to some extent, while the stiffness of SRC columns after exposure to fire can not be enhanced apparently when strengthened by CFRP. The stiffness of fire-damaged SRC columns with a relative large slenderness ratio can be enhanced in a certain extent when strengthened by external steel clad, but the stiffness rehabilitating effect of external steel clad on fire-exposed SRC columns with relative small slenderness ratios is not apparent. Compared with CFRP, the rehabilitating effect of external steel clad on load-bearing capacity of fire-damaged SRC columns is more remarkable. The ultimate strength of fire-damaged SRC columns can be fully restored when strengthened with extemal steel clad.