超长服役期正交异性桥面板主梁力学性能评估

Evaluation of mechanical properties of orthotropic deck girder with super long service life

为明确超长服役期正交异性桥面板主梁的力学性能,以运营33年的某钢主梁斜拉桥为例,基于现场检测结果,结合有限元模型,对正交异性桥面板的承载能力、刚度退化特征,以及疲劳性能进行了系统性的研究。结果表明:主梁承载能力依然可以满足规范要求,主梁节段连接处纵向连接减弱及桥面折角病害主要是由于节点处因锈蚀、开裂、连接盖板脱落导致的刚度下降,在汽车荷载反复疲劳作用形成的。纵肋-顶板焊缝以及横隔板-纵肋起焊点横向焊缝存在较高开裂风险。

To clarify the mechanical properties of of orthotropic deck girder with super long service life, a steel girder cable-stayed bridge with 33 years of service was taken as an example. Based on the field test results, combined with the finite element model, the bearing capacity, stiffness degradation characteristics and fatigue performance of the orthotropic deck were systematically studied. The results show that the bearing capacity of the main girder still meet the codes requirements. The weakening of longitudinal connection at the connection of main beam segments and the damage of bridge deck corner are mainly caused by the stiffness reduction at the joints due to corrosion, cracking and the falling off of connecting cover plates, which are formed under the repeated fatigue effect of vehicle loading. There is a high cracking risk in longitudinal rib roof weld and transverse weld of transverse diaphragm longitudinal rib starting point.