甬江铁路斜拉桥索塔塔梁同异步施工方法对比分析

Comparative Analysis of Synchronous and Asynchronous Construction of Tower and girder of Yongjiang Railway Cable Stayed Bridge

甬江特大桥为国内首座铁路大跨度钢箱混合梁斜拉桥,钻石形索塔高177.91 m。通过建立索塔与下横梁同、异步施工有限元模型,模拟分析同、异步施工对索塔受力状态及线形的影响。对比分析表明,同、异步施工的索塔受力及线形略有差异,均能满足设计要求,而异步施工较同步在工期上有较大优势。根据对比分析及南岸索塔工期滞后的实际情况,甬江特大桥南北岸索塔分别采用了塔梁异步与塔梁同步的施工方法,最后实现工期的同步,收到了良好的经济与社会效益。

The extra-long bridge of Yongjiang River is a domestic first large-span railway cable-stayedbridge with hybrid girder and 177.91 m diamond-type tower. In order to analyze the impact of synchronous and asynchronous constructions of tower and girder on the stress state and linearity of the tower, a finite element model is established to simulate the entire construction process. The comparative analysis reveals that the stress and line of the tower resulted from the two construction methods are of some difference, and both methods meet design requirement, but the asynchronous construction methodcan save much time. According to the comparative analysis and the actual lagging of the south cable- tower, the south tower and the north tower employ synchronous and asynchronous construction methodsrespectively, and as a consequence, the synchronization of progress and good economic and social benefits are obtained.