Predicting the shear strength of concrete beams with corroded rebar: a review and synthesis

The load-bearing mechanism in reinforced concrete beams with corroded rebar has not been clearly elucidated, impeding good shear strength predictions. A thorough literature review reveals the impact of rebar corrosion on the load-bearing mechanism of beams. A systematic validation confirms deficiencies in the current prediction approaches such as the failure to reflect changes in the load-bearing mechanism caused by rebar corrosion and insufficient consideration of the effects of key variables. Corrosion impact factors that reflect the enhancement of arch-action caused by main bar corrosion and the section loss of corroded stirrups are derived to better account for changes in the shear strength. The superiority of incorporating these impact factors into fundamental methods for intact beams is confirmed using ample published experimental data. Incorporating corrosion impact factors into Niwa’s formula is shown to yield the best predictions.

锈蚀钢筋混凝土梁的受力承载机理尚未得到清晰阐释，这极大制约了剪切强度的精准预测。本研究通过全面的文献综述，明确了钢筋锈蚀对梁体受力承载机理的影响。经系统性验证发现，现有剪切强度预测方法存在诸多不足：既未能反映钢筋锈蚀引发的受力承载机理变化，也对关键变量的影响考虑不足。本研究推导得到两类锈蚀影响因子，分别对应主筋锈蚀引发的拱作用（arch-action）增强效应，以及锈蚀箍筋的截面损失效应，以更好地适配剪切强度的变化规律。通过大量已公开的试验数据验证，将上述影响因子融入完好钢筋混凝土梁的基础剪切强度计算方法中，其有效性得到证实。进一步研究表明，将此类锈蚀影响因子引入Niwa公式后，可得到最优的剪切强度预测结果。