Abstract: The spatial mechanical effect of continuous girder bridge with wide box structure is obvious. Based on the actual project of single box three chambers continuous girder bridge with a top slab width of 25.4m, the spatial effect of single box three chambers continuous girder bridge under transverse temperature gradient and eccentric vehicle load was investigated. Based on the data fitting of the field measured temperature, the transverse temperature gradient was obtained. Midas/FEA finite element software was used to establish the solid finite element model of the whole bridge. The effect of the transverse temperature gradient and the eccentric vehicle load were analyzed, and the load effects of the two were combined. The results show that the measured characteristic value of the transverse temperature gradient obtained by fitting is much higher than the reference value of the current specification. When the effect of transverse temperature gradient is combined with the effect of eccentric vehicle load, the longitudinal stress and the transverse stress at the bottom slab of middle-span of the central span of single box three chambers continuous girder bridge no longer meet the crack resistance requirements of class A partially prestressed concrete structures under the short-term effect combination in the specification.

Key words: bridge engineering, single box three chambers continuous girder bridge, finite element analysis, transverse temperature gradient, eccentric vehicle load, load effect combination

摘要： 宽箱结构连续梁桥的空间力学效应明显。依托顶板宽度达25.4 m的某单箱三室连续梁桥实际工程，探究了单箱三室连续梁桥在横向温度梯度作用与汽车偏载下的空间效应。基于现场实测温度数据拟合得到实测横向温度梯度作用；利用midas/FEA有限元软件建立全桥实体有限元模型，分析横向温度梯度作用效应和汽车偏载效应，并将二者进行荷载效应组合。结果表明：拟合得到的实测横向温度梯度作用特征值远大于现行规范参考值；当实测横向温度梯度作用效应与汽车偏载效应组合后，单箱三室连续梁桥中跨跨中底板处纵向应力、横向应力不再满足规范中关于作用短期效应组合下A类部分预应力混凝土结构的抗裂性要求。

关键词: 桥梁工程, 单箱三室连续梁桥, 有限元分析, 横向温度梯度作用, 汽车偏载, 荷载效应组合