混凝土收缩徐变效应对含叠合梁段混合梁斜拉桥主梁受力行为的影响

Effect of concrete shrinkage and creep effection on the main girder′s mechanic behaviors of hybrid girder cable-stayed bridge with superposed beam

以某双塔混合梁斜拉桥为工程背景,利用桥梁专业软件Midas/Civil建立了全桥三维有限元模型;对比分析了在成桥阶段混凝土收缩徐变作用对斜拉桥主梁内力行为的影响.分析结果表明:混凝土收缩徐变效应对叠合主梁弯矩的影响较大,使其发生了内力重分布,对正弯矩具有削峰作用,造成负弯矩值有较大的增加,对混凝土主梁影响较小;收缩徐变效应对主梁轴力及剪力的影响均较小;混凝土的收缩徐变效应对叠合梁的受力影响较大,使叠合梁中钢梁与混凝土桥面板之间应力发生重分布,靠近钢-混凝土结合段处的混凝土主梁应力改变较大,其余位置改变量不明显.

The 3D finite element model of a hybrid beam cable-stayed bridge with double pylons located in china is established. Compared with the concrete beam, the effect of shrinkage and creep of concrete on the superposed beam is studied during finished state. And it turns out that the effect of shrinkage and creep of concrete on the superposed beam is much larger than the concrete beam as it leads to bending redistribution and curving pare peak that the negative bending increased. While, it has little effect on the axial force and shear force. Consequently, the stress of superposed beam is redistributed and the stress change of concrete segments near the steel-concrete composite structure is much larger while the others＇ is slight.