Abstract

Transportation infrastructure is of fundamental importance and must be regularly assessed to ensure its safety and serviceability. The assessment of ageing reinforced concrete bridge stock may need to consider corrosion and cracks, as the likelihood of deterioration increases with age. This work accordingly investigates the incorporation of pre-existing anchorage zone corrosion cracks into the finite element modelling of reinforced concrete beam structural behaviour. Three methods of accounting for cracks were applied: (1) modifying the bond stress–slip relation, (2) weakening elements at the position of the crack, and (3) weakened discrete crack elements. The results show that modifying the bond stress–slip relation results in accurate predictions of the ultimate capacity when one-dimensional reinforcement bars are used in the model. Weakening elements at the position of the crack provides reasonable results when the anchorage is modelled with three-dimensional reinforcement bars and a frictional bond model. The implementation of discrete cracks was found to be unsuitable for the studied load situation, as compressive stresses formed perpendicular to the crack. It was concluded that the capacity of the studied case could be well estimated based on visual measurements, without knowledge of the exact corrosion level.

摘要

交通基础设施至关重要，必须定期评估以确保其安全性和适用性。老化钢筋混凝土桥梁材料的评估可能需要考虑腐蚀和裂缝，因为老化的可能性随着年龄的增长而增加。因此，这项工作研究了将预先存在的锚固区腐蚀裂缝纳入钢筋混凝土梁结构行为的有限元建模。应用了三种计算裂纹的方法：(1) 修改粘结应力-滑移关系，(2) 裂纹位置处的弱化单元，以及 (3) 弱化离散裂纹单元。结果表明，当模型中使用一维钢筋时，修改粘结应力-滑移关系可以准确预测极限承载力。当使用三维钢筋和摩擦连接模型对锚固进行建模时，裂缝位置处的弱化单元提供了合理的结果。发现离散裂纹的实施不适用于所研究的载荷情况，因为压缩应力垂直于裂纹形成。得出的结论是，可以根据目视测量很好地估计所研究案例的容量，而无需了解确切的腐蚀水平。