连续钢箱梁桥正交异性板疲劳寿命预测

正交异性板以其重量轻、承载能力大、施工速度快和维护成本低等优点而广泛应用于各类桥梁中,然而与其优异性能相对应的是在车辆荷载作用下,复杂的构造和众多的焊缝引起的疲劳问题,进而影响到结构的安全性、适用性和耐久性。该文以某两跨连续钢箱梁桥为工程背景,通过建立全桥Midas-civil梁单元模型,运用子模型技术,建立Ansys节段子模型,采用《规范》中的疲劳荷载模型Ⅲ对钢箱梁正交异性板进行加载,得到3个疲劳关注点的应力历程,最后采用雨流计数法得到3个关注点的应力谱。按照Miner线性累积损伤理论,预测3个关注点的疲劳寿命均超过100年,满足设计要求。

Orthotropic plate is widely used in all kinds of bridges because of its light weight,large bearing capacity,fast construction speed,low maintenance cost and so on.However,its excellent performance corresponds to the fatigue problems caused by complex structure and numerous welds,which further affect the safety,applicability and durability of the structure.In this paper,taking a two-span continuous steel box girder bridge as the engineering background,the Midas-civil beam element model of the whole bridge is established,and the Ansys segment sub-model is established by using the sub-model technology.The fatigue load modelⅢin the Code is used to load the orthotropic plate of steel box girder,and the stress history of three fatigue concerns is obtained.Finally,the stress spectra of three concerns are obtained by rain flow counting method.According to Miner's linear cumulative damage theory,the fatigue life of the three concerns is predicted to be more than 100 years,which meets the design requirements.