石板坡长江大桥混凝土收缩与徐变效应分析

Analysis of Concrete Shrinkage and Creep's Effect for Shibanpo Bridge over Yangtze River

石板坡长江大桥位于重庆主城区,结构采用连续梁与连续刚构混合连续体系,主跨跨度在同类型桥梁中居世界之首。结合该桥设计及施工特点,采用按龄期调整的有效模量法结合有限元步进法对石板坡长江大桥混凝土收缩与徐变效应进行了计算分析。计算结果表明预应力筋的张拉、混凝土的收缩徐变等对桥梁的竖向变形与轴向变形都有较大影响,混凝土的收缩徐变以及预应力损失使该桥混凝土梁的应力减小,钢梁的应力增加。

Shibanpo bridge lies in the main district of Chongqing , the structure adopting the combination system of rigid frame bridge and continuous beam bridge, the main span being the longest in the world. According to the particularity of the bridge in design and construction, with the age-adjusted effective modulus method and the finite element Step-by-Step method, the effect of concrete shrinkage and creep on structural deformation and stress of the bridge is analyzed. The results show that the tension of prestressed steel tendon, shrinkage and creep of concrete have important influence on the vertical and longitudinal deformation of the beam. Furthermore, the shrinkage and creep of concrete and loss of prestress can result in a reduction in stress of the concrete box girder and an increase in stress of the steel box girder.