中文摘要：

预应力CFRP加固技术是近年来得到重视的新型加固方法,但目前国内外关于预应力碳纤维CFRP加固混凝土受弯构件的二次受力性能方面的研究较少。通过2根长7.2 m的大型钢筋混凝土梁试件预应力CFRP二次受力加固的试验研究,考察预先加载至钢筋屈服后再采用预应力CFRP加固的钢筋混凝土梁的力学性能,比较非预应力CFRP加固构件的一次受力性能与预应力CFRP加固构件的二次受力性能,分析预应力CFRP加固在抗弯刚度、延性、材料强度利用率等方面的优势。试验结果表明：在试件预先加载至纵向受力钢筋屈服的条件下对其进行加固,试件的承载能力仍然与没有加载历史的非预应力加固试件相当;虽然截面刚度极大削弱,试件变形仍与对比试件相近,说明结构严重超载后经预应力CFRP板加固,可恢复相当程度的抗弯刚度。

英文摘要：

Prestressing CFRP technique is a new retrofit method which gained more and more attention in recent years,but there is little research on the secondary load behavior of flexual member strengthened using prestressed CFRP plate at home and abroad.In this paper 2 reinforced concrete beams,which have a length of 7.2 m,were retrofitted with non-prestressed CFRP and prestressed CFRP respectively,and then were tested to investigate their secondary load performance.Based on the experiment result,the comparison of behavior between beam with non-prestressed CFRP plate and beam strengthened using prestressed CFRP after pre-loading was conducted.Furthermore,the advantages of flexual stiffness,ductility and material strength ratio were obtained through analyzing.The experiment result indicated that although having been loaded to its steel yielding before being strengthened,the specimen with prestressed CFRP plate had a bearing capacity no less than that with non-prestressed CFRP plate.Despite the degradation of its section,the defletion of the secondary load specimen was almost the same as the control specimen,which showed that strengthening reinforced concrete beams pre-loaded severely using prestressed CFRP plate could recover their flexural stiffness significantly.