中文摘要：

对7根自密实混凝土（SCC）加固梁和2根对比梁进行二次受力下的抗剪性能试验。试验采用三面U型增大截面形式,在初始受力不变的情况下进行自密实混凝土加固。研究不同初始受力,不同加固厚度及不同新老混凝土界面处理方式下加固梁的受剪破坏特征、承载力和新旧钢筋应变的变化规律。试验结果表明：采用自密实混凝土加固钢筋混凝土梁,新老混凝土共同工作性好,能够显著地提高钢筋混凝土梁的抗剪承载力。根据试验结果,得到二次受力下自密实混凝土加固梁的受剪承载力计算公式,计算结果与试验结果吻合较好。

英文摘要：

Seven initially loaded beams strengthened by self-compacting concrete（ SCC） and two comparative beams were experimentally investigated. The beam cross sections were U-shaped enlarged form by self-compacting concrete under constant initially load. With different initial load,the shear failure characteristics,bearing capacity and the change law of strain in the old steels and new steels were analyzed under different enlargement thickness and different interface treatments. The results show that the co-operational performance of the old concrete and new self-compacting concrete is good,which can significantly improve the shear bearing capacity in self-compacting concrete strengthened beams. According to the test results,the shear capacity formula of the beams strengthened by SCC under secondary load was obtained,and it showed good agreement with the experimental results.