最小配箍率下钢筋混凝土简支梁受剪性能试验研究

为研究配置最小配箍率有腹筋梁的受剪性能,以配箍率、剪跨比和混凝土强度为变量,完成了集中荷载作用下36根钢筋混凝土简支梁(12根无腹筋梁和24根有腹筋梁)的受剪性能试验,对其裂缝发展、破坏形态、临界斜裂缝倾角、主斜裂缝荷载、受剪承载力及跨中挠度等进行了分析.结果 表明,最小配箍梁与无腹筋梁的裂缝发展、破坏形态差异较大,剪...

Experimental study on shear behavior of simply supported reinforced concrete beams with minimum stirrup ratio

In order to study the shear behavior of beams with web reinforcement and minimum stirrup ratio, the shear test of 36 simply supported reinforced concrete beams (12 beams without web reinforcement and 24 beams with web reinforcement) under concentrated loading was carried out. The test variables included the stirrup ratio, shear span ratio and concrete strength. The crack development, failure mode, critical inclined crack angle, main diagonal crack load, shear bearing capacity and mid-span deflection were analyzed. The results show that there is a great difference between the beams with minimum stirrup ratio and the beams without web reinforcement in terms of the crack development and failure mode. The shear span ratio has a significant influence on the angle of critical inclined crack, and the stirrup efficiency coefficient is not less than 1.1. Based on the calculation formulas of minimum stirrup ratio in ACI 318-19, CSA A23.3-14, and BS EN 1992-1-1, the rationality of the minimum stirrup ratio in GB 50010—2010 was analyzed. Based on the test results presented in this paper and the shear test results in previous studies, including those for beams without web reinforcement, 116 normal-strength concrete beams and 90 high-strength concrete beams with minimum stirrup ratio, the safety degree of the calculation formula provided in GB 50010—2010 for beams without web reinforcement and with minimum stirrup ratio was evaluated. It is found that nearly 30% of the test results are lower than the calculation values of the formula provided by the code. On this basis, the calculation formula of shear capacity of beams with web reinforcement and a low stirrup ratio was proposed. It is suggested to adjust the minimum stirrup ratio in the code on the basis of reliability calibration.