小剪跨比锈蚀钢筋混凝土梁受剪性能试验研究

钢筋混凝土梁中箍筋发生锈蚀易导致结构性能退化以至失效破坏，为此针对HRB400钢筋作为箍筋发生锈蚀后的钢筋混凝土梁在剪跨比为1.5以下的受剪性能的退化展开研究。制作8根钢筋混凝土梁，按照剪跨比为1.5和1分成两组进行试验，比较未锈蚀和锈蚀后的钢筋性能以及试验梁的受剪承载力。研究结果表明：定义箍筋竖直段的锈蚀率为有效锈蚀率进行分析，能够有效反映箍筋的锈蚀程度和截面损失情况；箍筋有效锈蚀率小于20%时钢筋混凝土梁受剪承载力下降并不明显，当箍筋有效锈蚀率大于30%时受剪承载力下降明显，且剪跨比越大钢筋混凝土梁受剪承载力下降幅度越大；剪跨比小于1.5时，锈蚀箍筋性能退化对钢筋混凝土梁受剪承载力下降影响较小，受剪承载力下降主要是因为箍筋锈蚀引发锈胀裂缝导致核心混凝土整体性下降所致。

Experimental study on shear behavior of corroded reinforced concrete beams with low shear span ratio

Corrosion of stirrups in reinforced concrete beams can easily cause performance deterioration and even failure of concrete structures. This paper presented an experimental study on the shear performance of concrete beams which had corroded stirrups of HRB400 and low shear span ratios that were less than 1.5. A total of eight concrete beams was casted and divided into two groups according to the shear span ratio of 1.0 and 1.5. After the tests of these beams, a comparison of the performance of steel bars and load carrying capacity of beams without and with corrosion in stirrups was made, which led to the following conclusions. The effective corrosion ratio of stirrups should be defined according to the extent of corrosion of the bars in the vertical parts of stirrups, which can more accurately reflect the performance and section loss of corroded stirrups. The shear load carrying capacity of concrete beams does not significantly decrease when the corrosion ratio is less than 20%, while the shear capacity drops significantly when the corrosion ratio is beyond 30%. When the shear span ratio of these experimental beams is less than 1.5, the corroded stirrups has little effect on the decrease of shear capacity of beams, which is mainly because the corrosion cracks in the beams lead to the deficiency of integrity of the core concrete surrounded by stirrups.