靖皋长江大桥南航道桥南塔防撞方案研究

The south navigation channel bridge of Zhangjiagang-Jingjiang-Rugao Changjiang River Bridge is a two-tower, steel box girder suspension bridge, featuring its two unequal suspended spans, with the length of the main suspended span reaching 2300 m. The river traffic beneath the bridge is heavy, with a great portion of large-tonnage ships, thus increasing the ship impact risk of the south tower that stands in the river, and the calculated collision forces are big. Hanging soft fenders on the outer surface of the cofferdam comprising interlocking steel piles is recommended, which can fulfill the collision protection demands better than using the traditional passive collision protection measures. The interlocking steel piles cofferdam is placed to enclose the pile cap to be apron walls, upon which the soft fenders are hung, and energy dissipating material is filled in the gap between the cofferdam and the pile cap to achieve collision protection and energy dissipation. The apron walls also serve as water retaining facilities, as well as permanent scouring protection and ship collision energy dissipation structure. Ship-bridge collision simulation was conducted to verify the collision protection performance of the recommended collision protection structure and select proper energy dissipation material. It was determined to use sand to fill the gap between the apron walls and the pile cap, which can reduce 36.68% of the collision forces on the pile cap. The proposed collision protection structure is easy to be installed and quite economical in the future maintenance, and the only maintenance concern is to handle the corrosion of the steel piles.