正交异性钢桥面板足尺节段疲劳模型试验研究

Experimental study on fatigue features of orthotropic bridge deck through full-scale segment models

正交异性钢桥面板疲劳问题突出,试验研究是评估其疲劳性能并揭示其疲劳特性的重要途径。以港珠澳大桥钢箱梁为研究对象,通过足尺节段模型对于正交异性钢桥面板的疲劳强度及其疲劳性能评估的关键问题进行试验和理论研究。采用足尺节段模型对多个关键疲劳易损部位进行疲劳试验研究;通过多点异步加载模拟行车效应对于结构疲劳特性的影响;采用在模型不同位置加载的方式验证各关键疲劳易损部位在设计寿命期内的抗疲劳安全性;在此基础上对于重要疲劳易损部位的疲劳性能进行试验和理论研究,探讨关键疲劳易损部位的疲劳强度及其疲劳性能评估的名义应力法和热点应力法。研究结果表明,港珠澳大桥正交异性钢桥面板的疲劳性能满足设计要求且有一定的安全储备;各关键疲劳易损部位的疲劳特性和疲劳强度存在显著差异,热点应力法适用于正交异性钢桥面板关键疲劳易损部位的疲劳性能评估。

Model test is an important approach to evaluate fatigue resistance and reveal the fatigue characteristics of steel orthotropic bridge deck. Taking the steel box girder of the Hong Kong-Zhuhai-Macao Bridge as research objects,the key issues of fatigue strength and fatigue performance evaluation of steel orthotropic bridge deck were studied by full-scale girder segment model tests and theoretical study. The full-scale girder segment model were designed to study multiple fatigue details simultaneously. The influence of vehicle loading effects on structure fatigue was studied by a multi-point asynchronous loading scheme. The fatigue properties of vulnerable details were verified by the way of loading on different positions of model in design lifetime. Furthermore,fatigue properties tests and theoretical study on typical fatigue vulnerable details were carried out. Then the fatigue strength and fatigue properties evaluation of typical fatigue vulnerable details were investigated by the hot spot stress method. The results indicate that the fatigue properties of orthotropic steel decks of the Hong Kong-Zhuhai-Macao Bridge satisfy the requirements of design and have a certain safety margin. The fatigue strength and fatigue properties of typical fatigue vulnerable details are significantly different.The evaluation of fatigue resistance of typical fatigue vulnerable details of steel orthotropic bridge deck is feasible by hot spot stress method.