HRB500级钢筋配箍的混凝土梁受剪性能试验研究

Experimental study on the shear failure of reinforced concrete beams with grade HRB500 steel stirrups

利用一刚性试验系统,进行18根钢筋混凝土梁受剪性能试验。试验分为两个系列,一个系列采用HRB500级钢筋配箍的有腹筋梁,另一个系列为对应的无腹筋梁。主要试验变量为剪跨比和混凝土抗压强度。试验得到试验梁包括下降段在内的荷载-挠度全曲线。根据试验结果,分析梁的斜截面受剪承载力和变形性能。通过试验数据分析,发现剪跨比对有腹筋梁和无腹筋梁的受剪性能都有较大的影响,有腹筋梁的剪切破坏不属于脆性破坏,有腹筋梁使用阶段的斜裂缝宽度可以满足正常使用极限状态的要求。不同强度等级和不同剪跨比的混凝土梁,采用HRB500级钢筋作为箍筋,其受剪承载力可按现行《混凝土结构设计规范》有关公式进行计算,所得结果偏于安全。

An experimental investigation of the shear behavior of 18 reinforced concrete beams was conducted with a stiff test facility. Two series of beam tests were performed, with one series of beams being reinforced with grade HRB500 steel stirrups and the other series without web reinforcement. Primary parameters were the shear span-depth ratio and concrete compressive strength. The complete load-midspan deflection curves, including the post-peak portion, were obtained. Based on the experimental data and observations, the shear capacity and ductility of the beams are analyzed. It is shown that the shear span depth ratio significantly affects the shear behavior of the beams with or without web reinforcement, the failure of the beams with web reinforcement should not be considered as brittle, and the diagonal crack width of the beams with web reinforcement in service is within the criterion of the current Chinese design code. The shear capacity of beams with various grades of concrete and shear span depth ratios reinforced with grade HRB500 web reinforcement can be conservatively predicted with the formula in the current Chinese code.