多跨刚构-连续组合桥合龙方案及顶推性能分析

Closing scheme and pushing performance analysis of multi-span rigid structure-continuous composite bridge

多跨刚构-连续组合桥的合龙和顶推方案决定了桥梁结构的内力和线形。为选择董家潭湘江特大桥(70+5×120+70) m的最佳合龙顶推方案,采用有限元软件建立不施加顶推力时4种不同合龙方案的有限元模型,通过对比分析成桥后主梁的位移和应力,初选2种较优合龙方案;在此基础上分析顶推方案并得到3种顶推工况,以消除墩顶水平位移为原则分别确定各工况下的顶推力,对施加顶推力的3种工况进行力学分析,选出最佳合龙顶推方案;最后,针对最佳合龙顶推方案进行顶推局部建模分析。研究结果表明:由边跨向中跨依次对称合龙,在中跨合龙前施加1 900 kN顶推力为该桥最佳合龙顶推方案,该方案的顶推局部应力和变形均满足要求。

The closing and pushing scheme of multi-span rigid structure-continuous composite bridge determines the internal force and linear shape of the bridge.In order to choose the best closing and pushing scheme of Dongjiatan Xiangjiang River Bridge(70+5×120+70)m,finite element models were established with finite element software for four different closing schemes when no pushing force was applied.The displacement and stress of the main beam after bridge completion were analyzed by comparison,and two optimal closing schemes were selected.On this basis,three kinds of pushing conditions were obtained by pushing scheme analysis.Under the principle of eliminating the horizontal displacement of the pier top,the pushing force in each working condition was determined.The best closing and pushing scheme was selected by mechanical analysis of the three working conditions under which pushing force was applied.Finally,the local modeling analysis of pushing was carried out for the best closing and pushing scheme.Research results indicate that symmetrically closing the bridge from the side span to the middle span and applying a pushing force of 1900 kN before the closure of the middle span is the best closing and pushing scheme for the bridge.The local stress of pushing and deformation of the scheme meet the requirements.