马鞍山长江大桥中塔钢-混凝土叠合段施工关键技术

Key Construction Techniques of the Steel/Concrete Hybrid on the Middle Tower of Maanshan Yangtze River Bridge

马鞍山长江大桥中塔设计为钢-混凝土叠合塔,叠合段处于钢-混凝土结构过渡部分,钢塔荷载通过混凝土顶面直接传递,混凝土顶面与钢塔柱底座板接触的密贴性是保证结构安全的关键.通过试验确定叠合段混凝土配合比、施工工艺,开展1/4模型试验验证施工工艺的可靠性.在离钢塔柱2m处设置后浇混凝土叠合段,采用195cm自密实混凝土+5cm高性能砂浆,成功解决了叠合段混凝土浇筑难题.最后进行钢混接头无粘结预应力的张拉,确保了钢塔柱与混凝土塔柱之间无缝连接.

The design type of middle tower of Maanshan Yangtze River Bridge is steel/concrete hybrid tower.The hybrid part was located in the transition region of steel-concrete structure.The force of steel tower transfers directly to the top surface of the concrete,The adhesiveness between bottom surface of steel tower and top surface of concrete is critical to ensure the structural safety.Concrete mix proportion and construction technology were determined by experimental testing.1/4model test was conducted on site to verify the reliability of construction technology.Setting the post pouring concrete hybrid part at 2mdistance from steel tower,Using 195 cm self-compacting concrete and 5cm high performance mortar solved the concrete pouring problem of hybrid part successfully.Finally,unbonded prestressed were tensioning in steel concrete joint,made the steel pylon and concrete pylon connected seamlessly.