弯箱梁桥横截面上预应力钢束张拉次序研究

The tension sequence of prestressing steel strands for curved box girder bridges

针对润扬大桥世业洲互通D匝道桥,采用有限元进行预应力束模拟张拉。设计了多种可能张拉方案,通过计算分析这些不同张拉次序下曲线箱梁应力变化规律,按照使混凝土尽可能不出现拉力及应力变化最小的原则,比选确定预应力钢束的张拉先后次序。通过针对预应力张拉次序对箱梁变形及结构受力影响的理论分析,并结合计算结果,给出了针对弯箱梁预应力张拉施工的"先外后内,对称均衡"的弯箱梁横截面上的张拉次序原则。通过施工过程中的监控及后期监测,效果较好,研究成果对弯箱梁桥预应力钢束张拉具有一定的参考价值。

Tension modeling of ramp D of the Shiyezhou interchange of the Runyang Yangze River Highway Bridge was carried out by using the finite element method. Several tension plans were designed. Through analysis of stress variation of the box girder under different tension plans, proper tension sequence was confirmed based on the principle that the concrete should bear no tensile stress at all or the lowest possible tensile stress if necessary. Based on the computational results and the theoretical analysis of the effects of the tension sequence on the stress and deformation of the box girder, the transversal tension sequence principle of ‘outer first, then inner, symmetrical and balanced＇ was put forward. Through construction monitoring and long - term monitoring of the bridge, the results were proved useful and could be applied to similar projects.