CFRP加固T形截面RC连续梁试验与理论研究

Experimental and theoretic study of RC continuous beam with T-section strengthened by CFRP

对4根CFRP同时加固正、负弯矩区的T形截面两跨连续梁进行了试验,对CFRP加固连续梁的承载能力、裂缝开展、变形及碳纤维和钢筋的应力、应变情况进行了研究。结果表明:通过CFRP加固,连续梁的极限弯矩和屈服弯矩均得到较大提高;增强了连续梁的抗弯刚度,连续梁挠度至少减小60%;延缓了裂缝的出现,有效地减小了裂缝宽度、间距;U形箍可以保护底部CFRP,并提高CFRP的使用效率。验算了CFRP加固受弯构件的抗弯承载力计算公式并对其提出修改建议;对CFRP加固的连续梁进行了延性分析;分析了CFRP加固连续梁后的内力重分布情况并提出弯矩调幅系数。

Flexural loading tests were carried out on 4 RC continuous beams with T-section strengthened by CFRP in both positive moment and negative moment areas.The flexural capacity,cracks,strain and deformation of the beams were discussed.The results show that the ultimate moment and yield moment of the beam are increased sharply;the flexural stiffness is increased and the deflection is reduced by at least 60%;the width and the distance of cracks are reduced;the U-shaped hoop can protect the CFRP from stripping and raise its efficiency.The calculation formula of flexural capacity of continuous beams strengthened with CFRP is verified and modified with suggestions.The ductility of continuous beams strengthened with CFRP is studied.The redistribution of internal forces of strengthened beams is analyzed and the modified moment factor is proposed.