Hoop Prestressing Technique on Pylons of Wuhu Changjiang River Rail-cum-Road Bridge on Shangqiu-Hefei-Hangzhou Railway

The main bridge of Wuhu Changjiang River Rail-cum-Road Bridge on Shangqiu-Hefei-Hangzhou Railway is a box and truss composite girder cable-stayed bridge with a main span of 588 m which consists of double pylons and double cable planes. The parallel steel cables are adopted and the maximum tension of a single cable is 16 000 kN. The combination of an anchorage system of steel anchor beam cable and an anchorage system of prestressed parallel wire ring is adopted in the cable anchorage zone, and the #-shaped prestressed anchorage is adopted in the single-layer prestressed system. Prestressed wire bundles with 36φ7 mm high strength and low relaxation, of which the tensile strength is 1 670 MPa and the modulus of elasticity is 2.05×105 MPa, are adopted for prestressing. During the construction of the bridge pylons, a metal corrugated pipe with an inner diameter of 90 mm is pre-embedded to serve as a channel for prestressing. Wire bundles should be braided in advance, and tension end heading should be upset in advance, so that wire bundles are pierced after tower column template is removed. After the steel wire is pierced, the fixed end anchor plate is installed and the fixed end is cut, and then the fixed end heading is upset. After the strength of concrete for pylon column meets the requirements of specifications, tension is prestreesed by a 250 t piercing hydraulic jack, thereafter, the prestressed hole grouting is carried out, and finally the prestressed anchor mouth is closed to complete the prestressing construction. © 2019, Journal Press, China Railway Bridge Science Research Institute, Ltd. All right reserved.