长联大跨刚构-连续组合梁顶推合龙计算分析

Analysis on the Calculation of Jacking Closure of Long Span and Long Unit Rigid-frame Continuous Composite Beams

长联大跨刚构-连续组合梁合龙段的施工对桥梁结构的变形和后期受力有非常重要的影响。合龙顺序、顶推力及压重的确定,可以优化长联大跨刚构-连续组合梁在施工阶段和使用阶段结构的变形,改善桥梁结构的受力。文章结合某铁路桥工程实例,进行长联大跨刚构-连续组合梁顶推合龙的计算,并对各种合龙方案的变形及应力进行对比分析,选择最佳的施工方案,并为类似工程的设计提供借鉴,即在优化合龙顺序及顶推力后结构计算指标仍不满足规范要求时,可以在跨中合龙之前悬浇段上施加一定的压重,不仅简单可行,而且效果明显、操作方便。此方法最大的优点是:提高了梁体截面尺寸的利用率,节省了工程材料,且成桥后梁体的线型更加合理。

The closure segment construction of the long span and long unit continuous composite beams has very important influence on the deformation and the post stress of bridge structure. Determining the closure order,jacking force and weight can optimize the structure deformation in the construction phase and operational phase of the long span and long unit continuous composite beams,it can also improve the stress of the bridge structure. On the basis of practical projects of a railway bridge,the author conducted calculation on the closure jacking force,and compared and analyzed the deformation and stress for all kinds of the final closure plan,selected the best construction scheme,and provided a reference for similar projects. If optimization of the final closure order and jacking force,structural calculation index still could not meet the requirements of specification,a certain pressure on the suspend segment could be applied before the final closure. This construction method,which has telling effects,is not only simple and feasible,but also easy to operate. The advantages of the method are： it improves the utilization rate of beam section size,saves the engineering materials and optimizes the girder linetype of the bridge.