跨铁路咽喉区箱梁悬臂板切割工艺和应力测试

Cantilever Slab Cutting Technique and Stress Test of Box Girder Overpassing Railway Throat Area

北横通道新建2期工程位于上海市中心城区,为城市繁忙干道跨越铁路咽喉区的关键节点工程,共跨越8条铁路股道和轨道交通3、4号线。该项目施工影响因素极为复杂,对安全性的要求高。因此介绍了复杂受限条件下既有连续梁悬臂板切割工艺,包括切割方法、施工顺序、预应力再锚固工艺,以及施工防护平台的设计。同时对桥面板横向预应力进行了现场测试,了解了其永存预应力的情况。该案例可为类似上跨铁路桥梁新建、拆除工程施工提供借鉴,并揭示了运营多年后桥面板横向预应力的情况。

The new phase Ⅱ project of Beiheng passageway,locates in the downtown of Shanghai,is a key node project of busy urban roads crossing railway throat area.It crosses a total of eight railway tracks and rail transit line 3/4.Its'influencing factors of project construction are very complex and the safety requirements high.In this paper,the cutting technique of cantilever plate of continuous beam under complex and limited conditions,including the cutting method,construction sequence,prestressed re-anchoring technique,and the design of construction protection platform are introduced.At the same time,the transverse prestress of bridge deck is tested on site to know the permanent prestress.The paper can provide reference for new construction and demolition projects of similar overpass railway bridges,and show the situation of transverse preslress of bridge deck after many years of operation.