双幅同步转体矮塔斜拉桥设计

广州市增城区新新公路跨广深铁路桥采用(114+96)m双幅预应力混凝土矮塔斜拉桥分幅跨越既有铁路。该桥主桥为塔墩梁固结体系,主梁采用单箱三室截面斜腹板变高箱梁,为平衡跨度不对称引起的不平衡重,主跨与边跨板厚采用不对称设计。桥塔采用顺桥向人字形独柱混凝土塔,桥面以上高31.0 m;斜拉索采用强度为1860 MPa的钢绞线拉索,单索面双排扇形布置;主墩采用矩形实体混凝土墩,群桩基础。采用转体过程角度控制图指导双幅桥同步转体施工,转体结构最大悬臂长114 m,设计转体吨位为3.2万吨。经验算,结构各项性能指标均满足设计要求。

Design of Synchronized Rotation Construction of Twin-Deck Extradosed Bridge

The section of Xinxin Highway crossing the Guangzhou-Shenzhen Railway in Zengcheng District,Guangzhou is designed as a twin-deck prestressed concrete extradosed bridge with two spans of 114 m and 96 m.The bridge is of a fixed pylon-pier-girder system.The superstructure consists of variable-depth box girders containing three cells and inclined webs.For structural balance,the slabs in the main span and the side span are in different thickness.The pylon is a concrete structure shaped like the Chinese character“人”,rising 31.0 m above the deck.The stay cables,which are made of 1860 MPa steel strands,are fanned out in single cable plane on each side of the pylon.The main pier is a rectangular solid concrete pier supported on group pile foundation.Following the rotation process control chart,the synchronized rotation construction of the twin-deck bridge was conducted,with a maximum rotation cantilever of 114 m and rotation weight of 32000 t.The calculation results show that all the performance indexes of the structure can meet the design requirements.