正交异性钢桥面铺装层表面裂缝应力强度因子分析

Analysis of Stress Intensity Factor of Surface Crack in Pavement on Orthotropic Steel Bridge Deck

首先建立了正交异性钢桥面系三维断裂力学有限元模型,计算并对比了开裂铺装层与完好铺装层表面最大拉应变值,结果发现铺装层开裂后会使表面拉应变值减小,表明铺装层表面最大拉应变不适合作为带裂缝铺装层的设计指标,因为铺装层的疲劳破坏是由裂缝前沿的奇异应力场强度,即应力强度因子的大小所决定;接着计算了铺装层表面纵向裂缝和横向裂缝的应力强度因子值,分析了应力强度因子随荷载作用位置变化的规律,确定了轴载作用的最不利荷位。

This thesis presented the three-dimensional fracture-mechanics finite element model of the orthotropic steel bridge deck system, calculated and compared the maximum tension strain in the surface of the intact pavement and the cracked pavement.The comparison showed that the controlling index of the pavement fatigue is not the maximum tension strain, but the local singular stress or strain field, which is the stress intensity factor, Then, the stress intensity factors of the longitudinal and transverse cracks on the pavement surface were calculated. Based on the change of the stress intensity factor along with the change of the loading position of the axle-load, the worst loading position of the axle-load on the cracking pavement of the steel bridge deck was asceaained.