嘉绍大桥主航道桥为（70＋200＋5×428＋200＋70） m六塔七跨分幅式钢箱梁斜拉桥。为确保其顺利合龙，结合该桥六塔独柱（桥塔为弱柱结构）并设置竖向双排支座体系和跨中刚性铰等结构特点，按照结构运营状态达到设计理想状态为施工控制目标，采用有限元软件建立实体模型，对关键控制工况分别进行仿真分析，对其合龙工艺、合龙顺序进行研究。研究确定该桥按照无应力状态几何控制法进行顶推合龙施工的方案，7个合龙口按照边跨→中跨→次边跨→次中跨的合龙顺序进行逐次合龙，并对合龙过程中的顶推施工工艺、关键施工参数确定、主要控制手段及实施控制要点进行了阐述。实践证明，该合龙方案和合龙顺序高效、高精度地完成了该桥的顶推合龙施工。%The main navigational channel bridge of Jiashao Bridge ,with span arrangement of (70+200+ 5 × 428+200+70) m ,is a six‐pylon seven‐span steel box girder cable‐stayed bridge with left and right separated decks .The bridge pylons are single‐columned pylons ,belonging to flexible structure .The bridge has the salient features of using double‐row bearing system and in‐stalling rigid hinges in the midspans .The construction control aim is set ,assuming that the service condition of the structure reaches the ideal designed state .The finite element software was used to establish the solid model of the bridge to do simulation analysis of the key control load cases and study the closure techniques and procedures .According to the results of the study ,the pushing construction technique based on the unstressed state geometrical control method for the bridge was determined .The seven closure gaps were closed following the sequence of side span→intermediate span→subsidiary side span→subsidiary intermediate span .And the pushing technique ,determina‐tion of the key construction parameters ,main control measures and key control points in the imple‐mentation of the measures during the closing process were elaborated .The engineering practice proves that by applying the proposed closure scheme and sequence ,the pushing closure construc‐tion of the bridge were completed with high efficiency and precision .
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