预应力混凝土组合桁架拱桥主要参数分析

Parameters Analysis of Trussed Combination Arch Bridge

组合桁拱是桁架拱和桁架梁的继承和发展，它结合了桁架拱和桁架梁的优点，组合成一种新型的组合桁拱体系，它既有桁架梁的受力特点，又发挥了桁架拱的优势，并利用预应力技术，使组合桁拱的杆件断面设计得既轻巧又美观，跨越能力更大，在大跨径桥梁结构中占有一席之地．目前最大跨径为３３０ｍ．为此以浙江省千岛湖石门大桥为工程背景，对影响组合桁拱结构受力性能的设计参数进行了分析，结合组合桁拱桥施工方法。

Trussed combination arch bridges are the inheritance and development of arch bridges and truss bridges. With the advantages of trussed arch bridges and trussed beam bridges combined in one system, the internal forces of superchord and subchord are distributed reasonably, avoiding such disadvantangous situation that the axial tension force of superchord in truss beam bridges and the moment in vault and abutment tend to be too large. With the implementation of prestress technology the member sections of trussed combination arch can be designed slimly and beautifully and are suitable for long span bridges, which makes trussed combination arch a good type of structure for long span bridges. The largest span of this structure up to now is 300 m. Based on Shimen Bridge in Qiandao Lake, Zhejiang province, this paper studies a new structure of prestressed concrete trussed combination arch, compares the mechanical properties of the trussed arch with truss and trussed combination arch, and analyses design parameters which influence the mechanical properties of the trussed combination arch. This paper puts forward the reasonable design parameters for trussed combination arch bridges.