宁波舟山港主通道北通航孔桥主墩承台封底关键技术

宁波舟山港主通道北通航孔桥为(125 十260 十125)m的钢-混凝土混合梁连续刚构桥.主墩承台下设13根φ3.5 m/3.0 m变径钻孔灌注桩,承台采用40 mX22.6mX8m的永久性防撞钢套箱施工,防撞钢套箱下放后进行封底混凝土施工.利用MIDAS Civil软件建立防撞钢套箱结构整体有限元模型,对承台施工阶段...

Key Pile Cap Base Sealing Techniques for Main Piers of North Navigational Channel Bridge of Ningbo-Zhoushan Port Main Link

The north navigational channel bridge of Ningbo-Zhoushan Port Main Link is a steel-concrete hybrid girder continuous rigid-frame bridge with three spans of 125,260 and 125 m.The pile cap of the main pier is supported by 13 bored piles of 3.5 m diameter(varying 3.0 diameter locally).A permanent anti-collision steel box cofferdam with dimension of 40 m×22.6 m×8 m was utilized for the pile cap construction.When the anti-collision steel box cofferdam was lowere d into position,the base-sealing concreting work began.The global model of the anti collision steel box cofferdam was established by MIDAS Civil,to predict the loading condition of base sealing concrete under different forces in different construction stages of the pile cap.According to the calculation,the thickness of the C30 concrete base was determined at 2.21 m.The concrete was fed by hoppers.During the base-sealing concreting,a working platform was built,feeding points were arranged,and the concreting was carried out and moved from one feeding point to another,inwardly circling and extending from center towards edges.Though challenged by the harsh marine environment,the base-sealing concreting work was a success,with no water permeating and leaking phenomenon observed.