正交异性钢桥面板纵肋与横隔板交叉构造细节疲劳开裂快速加固方法

为研究钢桥面板疲劳开裂局部区域引入钢或高性能材料加固构件的装配式加固方法，以钢桥面板纵肋与横隔板交叉构造细节为研究对象，采用足尺模型试验对钢桥面板纵肋与横隔板交叉构造细节疲劳性能劣化及其疲劳开裂的栓接角钢装配式快速加固相关关键问题进行了试验和理论研究；基于断裂力学探究了纵肋与横隔板交叉构造细节三维疲劳裂纹的扩展特性、疲劳寿命预测及装配式快速加固方法的加固效果。研究结果表明：纵肋与横隔板交叉构造细节的疲劳裂纹萌生于焊趾并沿纵肋腹板进行扩展，其对结构力学特性的影响范围和程度随着裂纹的扩展而逐步加剧；加固后相应开裂部位关键测点和裂尖各测点的应力应变降幅分别达57%和80%，装配式加固构件与既有结构协同受力性能良好，能够有效抑制局部疲劳裂纹扩展；数值断裂力学分析表明，加固后裂尖应力强度因子降幅达90%，可有效抑制疲劳裂纹的进一步扩展。

Rapid Reinforcement Approach for the Fatigue Cracking of Longitudinal Rib-to-diaphragm Detail in Orthotropic Steel Bridge Deck

To study an assembly rapid reinforcement approach by introducing components of steel or high-performance materials for fatigue cracks in an orthotropic steel bridge deck, the welded details of longitudinal rib-to-diaphragm are taken as the subject investigated; Two full-scale test models were used to study fatigue performance degradation and assembly rapid reinforcement method for fatigue cracks in the longitudinal rib-to-diaphragm welded joint. Numerical fracture mechanics was adopted to investigate the three-dimensional fatigue crack propagation, fatigue life prediction, and reinforcement effect of assembly rapid reinforcement method in the longitudinal rib-to-diaphragm welded joint. The results indicate that the fatigue crack is initiated from the toe of the longitudinal rib-to-diaphragm welded joint and expands along the longitudinal web, and the impact area and extent of its structural mechanical properties are gradually exacerbated. The stress and strain of typical testing points and the crack tip is reduced by 57% and 80%, respectively, after reinforcement; the reinforcement of the assembly reinforcement method works in good agreement with the existing structure and effectively inhibits the local fatigue crack propagation. The numerical fracture mechanics analysis demonstrated that the stress intensity factor is decreased by 90% and effectively prevents fatigue crack propagation.