元洪航道桥墩旁托架施工关键技术

平潭海峡公铁大桥处于典型的大风海洋环境,其中元洪航道桥为双塔双索面钢桁-混凝土混合梁斜拉桥,边墩、辅助墩及主塔墩顶钢梁均采用浮吊起吊,并安放至墩旁托架上。墩旁托架不仅须承受斜拉索挂设前钢梁自重及架梁吊机的重量,还须满足钢梁纵移滑动、安装调整及抗台风等功能要求。面对平潭海峡恶劣的海洋环境,尽量减少现场作业工作量和时间,墩旁托架采用工厂制造成整体,再利用大型浮吊整体安装的施工工艺。为确保结构安全可靠,该文采取在墩旁托架柱头和柱脚内填充C50微膨胀混凝土进行加固,并在大小里程两侧墩旁托架中施加预应力等措施。

The Pingtan Strait Highway and Railway Bridge is in a typical windy marine environment,in which Yuanhong Channel Bridge is a double-tower and double-cable plane steel truss-concrete hybrid cable-stayed bridge.The side pier,the auxiliary pier and the steel beam at the top of the main tower pier are lifted by floating crane and placed on the pier bracket.The bracket beside the pier should not only bear the dead weight of the steel beam before the cable-stayed cable is installed and the weight of the crane,but also meet the functional requirements of longitudinal movement and sliding of the steel beam,installation and adjustment and typhoon resistance.In the face of the harsh marine environment of Pingtan Strait,the workload and time of on-site operation should be reduced as much as possible.The bracket beside the pier is made into a whole by factory,and then the construction technology of integral installation of large floating crane is used.In order to ensure the safety and reliability of the structure,measures such as filling C50 micro-expansive concrete into the head and foot of the bracket beside the pier are adopted,and prestress is applied in the bracket beside the pier on both sides of the mileage.