佛山平胜大桥全桥模型试验研究

A total bridge model study of the Pingsheng Bridge in Foshan

广东佛山平胜大桥是世界首座独塔、单跨悬吊钢混结合梁的自锚式悬索桥,跨度达350m。本文利用全桥模型研究这种新型结构的体系转换过程和结构在荷载作用下的响应,重点介绍了该桥全桥静动力试验模型的结构设计及关键技术、试验过程和试验研究结果。自锚式悬索桥的试验模型在满足相似条件方面需要考虑加劲梁压缩变形的影响;在结构体系转换过程中,虽然主缆等的变形是几何非线性的,但由于结构的成桥内力状态与吊索张拉顺序无关,因此各种体系转换过程都能实现要求的线形。无应力长度控制法是确定自锚式悬索桥体系转换过程中的张拉力和结构状态较好的方法;在活载作用下,自锚式悬索桥的受力特性表现为线性的,自锚式悬索桥与地锚式悬索桥力学特性上既有一些相同的地方,又有较大的差异。

Pingsheng Bridge in Foshan is the first single-tower and single-span hybrid girder self-anchored suspension bridge with a main span of 350m. Making use of a total bridge model, the system transition process and structure response are studied. The structure design and key technologies, model test process and static and dynamic test results of the total bridge model are introduced. In the test model of the bridge, the influence of compression and deformation of stiffening girders must be considered to satisfy the similarity conditions. During the course of transition of the structural system, the main cable＇s deformation is nonlinear, whereas since the structural internal force is unrelated with the order of hanger tensioning, the demanded line shape can be realized for all the transitions. Control of the unstressed length is a proper method for determining the tensile force and the structure states in the course of transition of the self-anchored suspension bridge. Under live load, the mechanical properties of self-anchored suspension bridges are linear. Some mechanical properties of self-anchored suspension bridges and earth-anchored suspension bridges are alike, while others different.