火灾后碳纤维布约束混凝土棱柱体受力性能试验研究及分析

目前,火灾后CFRP约束混凝土棱柱体应力-应变关系模型尚未发现,给混凝土受压构件火灾后碳纤维布加固力学性能的研究带来了极大的不便。该文综合考虑多种影响因素,对火灾后CFRP约束混凝土棱柱体应力-应变关系进行了试验研究。试验结果表明,火灾后CFRP约束混凝土棱柱体能大幅提高其强度;火灾后CFRP约束混凝土棱柱体在曾达最高温度,转角半径、CFRP用量相同的情况下,布幅宽因素对其特征参数和应力-应变全曲线的影响较小;温度因素、用量因素以及转角半径因素对火灾后CFRP约束混凝土棱柱体的特征参数均有不同程度的影响。根据试验结果提出的火灾后CFRP约束混凝土棱柱体的应力-应变关系模型与试验曲线大致吻合,具有较好的精度,为混凝土结构火灾后加固的精确计算奠定了可靠的基础。

EXPERIMENTAL STUDY ON STRESS-STRAIN RELATIONSHIP OF CFRP-CONFINED CONCRETE PRISM AFTER FIRE

The stress-strain relationship model of concrete prism confined by CFRP after fire is scarce, which gives great trouble after fire to the study of mechanical properties of compressed concrete member strengthened by CFRP. Based on some influencing factors, stress-strain relationship of concrete prism confined by CFRP after fire is analysed. Experimental results indicate that strength of concrete prism after fire have a large certain extent increase as the result of the action of CFRP. Fabric breadth has a little influence to its characteristic parameters and stress-strain curve, when the greatest temperature, fillet radius and quantity of CFRP don’t change. Temperatures, quantity of CFRP and fillet radius have different extent influence to its characteristic parameters. Based on the experimental results, the stress-strain relationship model of the concrete prism confined by CFRP after fire has been proposed, which is nearly consistent with experimental curves and has better precision. This has established a reliable foundation for the accurate calculation of concrete structures strengthened by CFRP after fire.