（同济大学建筑工程系， 上海 200092）

［摘要］对4根体外预应力筋加固的混凝土简支梁进行了单调静载试验，研究了其荷载-挠度曲线、裂缝开展情况以及破坏特征。结果表明：整个加载过程可分为初期弹性工作阶段、带裂缝工作阶段、卸载后张拉预应力钢筋阶段、再加载至原有裂缝重新展开阶段和破坏阶段；试件的破坏源自非预应力钢筋的受拉屈服，破坏时变形明显，为延性破坏；相比加固前，加固后低强度混凝土（C15）梁承载力平均提高了1-08倍，而对比混凝土（C35）梁承载力则平均提高了1-94倍；低强度混凝土梁裂缝开展情况与对比混凝土梁类似。采用预应力筋对低强度混凝土梁进行体外预应力加固起到了预期的加固效果。

［关键词］体外预应力加固； 低强度混凝土； 试验研究

中图分类号：TU375-1文献标识码：A文章编号：1002-848X(2018)06-0031-04

Experimental study on low strength concrete simply supported beam reinforced by external prestressing

Cai Huiju, Zhou Jianmin

(Department of Building Engineering, Tongji University, Shanghai 200092, China)

Abstract:The monotonic static load test of 4  concrete simply supported beams strengthened with external prestressing tendons was carried out. The load-deflection curve, crack propagation and failure characteristics were studied. The results show that the whole loading process includes the initial elastic working stage, working stage with the crack and the stage when to stretch the prestressed tendons after unloading to redevelop the original cracks in re-loading stage, and failure stage. Specimen damage comes from the tension yield of non-prestressed tendons, and the ductile failure deformation is obvious. Compared with ultimate load before the reinforcement, bearing capacity of low strength reinforced concrote (C15)   beams after reinforcement is improved by 1-08 times, while the bearing capacity of concrete(C35)  beam  is improved by 1-94 times. The crack development of low strength concrete beam is similar to comparison beams. The external prestressing reinforcement on low strength concrete beams realizes the expected reinforcement effect.

Keywords:external prestressing reinforcement; low strength concrete; experimental study

*国家重点研发计划项目（2016YFC0700700）。

作者简介：蔡惠菊,硕士,讲师，Email:caihuiju@tongji.edu.cn。