宁波机场路南延工程为公轨一体化双层高架工程，根据目前大力发展预制结构和注重环保的工程建设要求，进行精细化设计，重点在快速施工、减振降噪、U型轨道梁顶疏散平台等方面进行设计研究。结合宁波机场路南延工程，从精细化设计的角度介绍公轨一体化双层高架桥的设计要点。通过上、下层分别梁上运梁、共用一套架桥机的工艺创新，实现双层预制梁结构应用，即在闭口型框架桥墩的上下层均采用预制轨道梁，极大地提高了双层高架桥的施工速度。减振降噪措施方面涉及U型轨道梁构造优化、声屏障设置、减振降噪伸缩缝等。研究U型轨道梁内腹板顶兼作疏散平台时，平台与车厢底板的位置关系。

The south road extension of Ningbo Airport Road is a project that involves a double-deck viaduct with an expressway and rail integration. According to the requirements for developing precast structures and the demands of environmental protection, refined designs are needed. This study focused on designs for rapid construction, noise reduction, and top evacuation platforms of U-shaped track girders. In view of the refined design method, this investigation introduced key points for a double-deck viaduct with highway and rail integration. By sharing technological innovations of a bridge erection machine, a double precast beam can be built, i.e. the lower deck also uses a precast track beam on a closed-frame pier. This method significantly improves the construction speed of a double-deck viaduct. The measures of noise reduction involve the optimization of a U-shaped track beam structure, setting a noise barrier, and designing expansion joints that decrease vibration and noise. The paper also investigated the position relationship between the platform and the floor of the carriage when the web roof of the U-shaped track beam is used as an evacuation platform.

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