都香高速金沙江大桥总体设计

都香高速金沙江大桥主桥采用跨径布置为(340+72+48+32)m的独塔斜拉桥。主梁采用钢-混混合梁,主跨为分离式双边箱的PK钢箱梁,边跨为整体式混凝土箱梁,钢-混结合面位于主跨距桥塔中心线12.4m处。桥塔采用钻石形混凝土结构,总高197.6m,其下布置整体式承台,钻孔灌注桩群桩基础。斜拉索按空间扇形双索面布置,每个空间索面设20对斜拉索,斜拉索采用1 770MPa高强度低松弛平行钢丝束。塔上索距为2.0~4.0m;梁上索距在钢箱梁段为16m,在混凝土箱梁段为8m、4.5m两种。塔端采用预应力锚固,梁端采用钢锚箱锚固。该桥桥塔采用爬模法施工,钢梁采用悬臂拼装法施工,混凝土箱梁采用支架现浇施工。

Overall Design of Jinsha River Bridge on Duyun-Shangri-La Expressway

The main bridge of the Jinsha River Bridge on Duyun-Shangri-La Expressway is designed as a (340+72+48+32) m single-pylon cable-stayed bridge. The main girder is composed of steel-concrete hybrid girder, the main span of which consists of PK steel box girder with separated double edge boxes, and the side span of which consists of integral concrete box girder. The steel-concrete interface is located at the main span, 12.4 m from the center line of the bridge pylon. A diamond-shaped concrete structure is adopted in the bridge pylon with a height of 197.6 m. An integral pile cap and a pile group foundation of bored piles are set under the pylon. The stay cables are arranged in spatial fan shape in double cable planes. Each spatial cable plane includes 20 pairs of stay cables. The stay cables are made of 1 770 MPa high-strength and low-relaxation parallel steel wire strands. The cable distances on pylon are 2.0 m to 4.0 m, while the cable distances on girder are 16 m in the steel box girder sections and 8 m or 4.5 m in the concrete box girder sections. The stay cables are anchored by prestressing at the pylon, while they are anchored by steel anchor boxes at the girder. In the process of construction, the methods of climbing formwork, cantilevered assembling, and support cast-in-place building are employed for constructing the pylon, the steel girder, and the concrete box girder, respectively.