在既有跨河公路桥上新建高架桥基础吊装设计与施工

跨越金清港河道的(35+60+60+35)m新建高架桥,正下方为正常使用的麻车大桥。受航道等级的影响,施工过程中无法采用大型浮吊进行吊装作业,麻车大桥也无法承载大型吊装设备的直接吊装施工。综合比选了“钢平台+履带吊”、“钢平台+卷扬机”与“钢平台+起重支架”吊装方案,确定采用“钢平台+起重支架”法进行新建高架桥基础的吊装施工。先利用麻车大桥辅助搭设钢平台,钢平台钢管桩入土稳定后安装起重支架,形成钢平台+起重支架系统,利用该系统完成了基础钢筋笼的起吊、安装;施工期间实时监测支架及桥梁地面变形,确保了基础吊装施工安全。

Design and Construction of Foundation of a Viaduct over Existing River-Crossing Highway Bridge

A newly-built viaduct crossing the Jinqinggang waterway has span distribution of 35,60,60 and 35 m,under which is the normally in-service Mache Bridge.Limited by the shipping grade of the river,the large floating crane cannot be used for the construction of the viaduct,and the Mache Bridge is also not capable of carrying large-scale lifting equipment.Three schemes were compared,including the scheme of using steel platform and crawler crane,the scheme of using steel platform and winches,and the scheme of using steel platform and lifting frames,and the third one was finally chosen for the lifting and installation of the foundation of the newly-built viaduct.First,the Mache Bridge was relied to install the steel platform,when the steel piles of the steel platform were stable in soil,the lifting frames were installed to form a steel platform and lifting frame system,via which the reinforcement cages of the foundation were lifted and installed.During the construction,the deformation of the lifting frames and the ground at the bridge site were monitored in real time to ensure the safety of the foundation construction.