滨海互通承台无封底钢混组合吊箱围堰施工关键技术

Key Technology for Construction of Steel-concrete Composite Suspending Cofferdam without Bottom Cover for Platform of Coastal Intercommunication Project

杭甬(杭州至宁波)高速公路复线宁波段一期滨海互通工程桥墩众多,受桥址处潮汐影响,高桩承台采用无封底吊箱围堰施工。综合对比了施工难度、安全、成本、工期等多方面因素,吊箱围堰底板采用水泥底板。无封底钢混组合吊箱围堰采用钢壁板+预制水泥底板结构,分块壁板之间采用螺栓连接。钢混组合吊箱采用后场预制底板及壁板,在钢护筒上焊接承重牛腿,将预制底板分块吊装到钢护筒牛腿上,浇筑预制底板间湿接缝,然后安装侧板,焊接剪力板,浇筑垫层,最后进行承台施工。在项目施工过程中,优化了壁板与底板的连接方式,从精轧螺纹钢吊杆连接改为钢筋对拉,提高了施工效率。

Many bridge piers were built in the Coastal Interconnection Project of the Ningbo Section of the Hangzhou-Ningbo Expressway Double Line.Affected by the tides at the bridge site,the high pile caps are constructed using a suspending cofferdam without a bottom cover.Based on the consideration of various factors such as construction difficulty,safety,cost and construction period,etc.,A cement structure is generally adopted as the floor of the suspended box cofferdam.The steel-concrete combined hanging box cofferdam without bottom cover adopts the structure of steel wall plate and prefabricated cement floor,and the partition wall plates are connected by bolts.The steel-concrete composite suspending cofferdam adopts the prefabricated bottom plate and wall plate.The construction sequence is listed as follows:First,weld the load-bearing corbel on the steel casing,and then hoist the prefabricated bottom plate to the steel casing corbel in blocks.Pour the wet joint between the prefabricated bottom plate and install the side plate.After that,pour the cushion after welding the shear plate.Finally,carry out the construction of the cap.During the construction of the project,the connection method between the wall plate and the bottom plate was optimized.The connection of the fine-rolled rebar hanger rod was changed to the steel bar pair pulling,which improved the construction efficiency significantly.