在役简支钢箱梁桥承载力研究

STUDY ON BEARING CAPACITY OF CORRODED IN-SERVICE SIMPLY SUPPORTED STEEL BOX GIRDER BRIDGE

为考察在役中等跨径钢箱梁桥的受力性能,以104国道绍兴高桥立交桥工程中D匝道钢箱梁桥为研究对象,采用幂函数模型对工业大气环境下钢箱梁的腐蚀率进行定量预测,利用MIDAS CIVIL 2013有限元软件建立考虑腐蚀损失的全桥三维有限元板壳模型,并对不同腐蚀年限的模型进行计算。基于计算结果,研究腐蚀对整桥刚度、强度、局部稳定以及动力特性的影响。结果表明:工业大气腐蚀作用会导致整桥竖向抗弯刚度降低,竖向挠度增大;桥梁关键部位应力增大,承载能力降低;桥梁竖向一阶振动频率减小。

In order to investigate the mechanical performance of in-service medium span steel box girder bridge, a steel box girder bridge of D ramp of 104 National Highway overpass project in Shaoxing was taken as the research object, and power function model was used to quantitatively predict the corrosion rate of steel box girder under industrial atmospheric environment, meanwhile, finite element software MIDAS CIVIL 2013 was adopted to establish three-dimensional full-bridge finite element plate shell models, which the corrosion losses was considered and the models of different corrosion years were also calculated. Based on the results, the corrosive effect on stiffness, strength, local stability and dynamic characteristics of the entire bridge were studied. The results showed that the corrosive effect of industrial air could cause the vertical bending stiffness of the entire bridge decreases, vertical deflection and the stress of bridge key parts increases, the bearing capacity and the vertical first order vibration frequency of bridge decreases.