港珠澳大桥青州航道桥工程特点及关键技术

Engineering Characteristics and Key Techniques of Qingzhou Ship Channel Bridge of Hong Kong-Zhuhai-Macao Bridge

港珠澳大桥青州航道桥为双塔双索面钢箱梁斜拉桥,该桥设计采用了多项新材料、新技术、新工艺,对其工程特点及关键技术进行总结。该桥充分利用相邻非通航孔桥相同结构类型的钢箱梁进行配重,外边跨不设置斜拉索,因地制宜,综合优势明显;结构支承体系采用三向支承体系,保证全桥结构性能最优;桥塔采用"中国结"造型的钢剪刀撑,与混凝土塔柱采用"承压-传剪"复合传力模式的连接箱连接,性能安全可靠;基础采用变直径钢管复合桩,钢管与钢筋混凝土组成组合截面共同受力,经济合理;桥墩墩身采用节段预制、现场安装的方案,节段连接采用75mm的预应力粗钢筋;钢箱梁采用优化的扁平流线型断面和正交异性钢桥面板,抗疲劳性能优越;斜拉索采用抗拉强度为1860MPa的平行钢丝索。

The Qingzhou Ship Channel Bridge of the Hong Kong-Zhuhai-Macao Bridge is a steel box girder cable-stayed bridge with double pylons and double cable planes. In the design of the bridge, a variety of the new materials, new techniques and new workmanships have been applied. In this paper, the engineering characteristics and key techniques of the bridge are summarized. On the bridge, the steel box girders of the same structural types of the adjacent non-navigable span bridges are fully used as the counterweight and on the outer side spans of the bridge, the stay cables are not installed. The arrangement of the bridge in such a way is well appropriate to the local conditions of the bridge site and has notable comprehensive advantage. The structural support system of the bridge is the three-way system that can ensure the structural performance of the whole bridge to be optimal. The pylons have the crisscross steel struts of the ＂Chinese Knot＂ configuration, which are connected with the concrete pylon columns via the connecting bo- xes in a combined force transmitting mode of ＂ compression-shear＂ and the performance of the steel struts and connection is safe and reliable. The foundations for the bridge are the composite piles of variable diameter steel pipes and together with the reinforced concrete in the steel pipes, the composite sections of the piles that are to jointly bear the loads and are cost-saving and rational are formed. The pier shafts are formed by the precast segments. The segments are installed at the site and are connected each other by the 475 mm thick prestressing bars. The steel box girders are of the optimized streamlined flat sections topped with the orthotropic steel deck plates and the fatigue performance of the girders are quite superior. The stay cables are the ones made up of the parallel steel wires and having tensile strength of 1 860 MPa.