鄂东长江公路大桥设计关键技术

Key Techniques for Design of Edong Changjiang River Highway Bridge

鄂东长江公路大桥主桥为主跨926m的双塔双索面半飘浮体系混合梁斜拉桥,主梁采用分离式双箱PK断面形式,中跨为钢箱梁,边跨为PC箱梁,钢-混凝土结合段设于中跨距桥塔中心12.5m处。为使钢结构与混凝土结构平稳过渡,钢-混凝土结合段采用PBL剪力连接器的多格室传力构造。索塔锚固采用在塔柱内置钢锚箱的构造,为控制锚固区混凝土裂缝开展,在锚固侧混凝土塔壁内设置12фs15.24预应力束。为增强结构耐久性和使用寿命,进行钢筋混凝土耐久性及钢结构防腐设计;采用全寿命设计理念,设置桥梁各主要构件检查维护通道,提出构件检查、维护周期及更换标准、工艺及技术要求。

The main bridge of Edong Changjiang River Highway Bridge is a semi-floating system hybrid girder cable-stayed bridge with double pylons,double cable planes and with a main span 926 m.The main girder of the bridge was designed as the PK（Pasco-Kennewick Bridge） cross section of separated twin boxes,of which the part of the girder for the central span is of the steel box girder,the parts of the girder for the side spans are of the prestressed concrete（PC） box girders and a steel and concrete joint section was set on each side of the central span at a distance of 12.5 m to the center of a pylon.To ensure a smooth transition between the steel and concrete structure,the multi-cell force transmission structure with PBL shear connectors was used for the joint section.The cable-to-pylon anchorage is the steel anchor box structure built in the column of a pylon.To control the development of concrete cracks in the anchorage zone in the pylon,the prestressing strands of 12фs15.24 were set in the concrete pylon wall on the side of the anchorage.To enhance the structural durability and service life,the durability of reinforced concrete and corrosion protection of steel structure were designed and the life cycle cost concept was applide to the design.The inspection and maintenance accesses for all principal components of the bridge were provided and the inspection and maintenance cycles,replacement criteria,workmanship and technical requirements were formulated as well.