独塔对称自锚式悬索桥简化解析解研究

Simplified analytical solution of symmetrical self-anchored suspension bridge with single tower

自锚式悬索桥在初步设计阶段,需频繁修改设计和变更计算参数,工作量大,迫切需要一种快速求解的方法,使设计人员迅速了解桥梁受力状态及其随参数变化的情况。为此,根据独塔对称自锚式悬索桥的受力特点,基于最小势能原理,提出一种求解内力和变形的简化解析方法。将自锚式悬索桥分离为加劲梁体系和主缆体系,分别计算恒载和活载作用下的吊索力。根据加劲梁梁端与主缆锚固点在顺桥向变形协调条件,求出活载作用下主缆水平分力,由此推导出独塔对称自锚式悬索桥内力和变形的简化解析解。并以主跨(150+150) m九乔路自锚式悬索桥为算例,分别采用本文方法和有限元法进行对比计算分析。研究结果表明:2种方法的计算结果吻合较好,且分布规律基本一致,竖向挠度和索力的计算值2种方法相差在15%以内。本文提出的简化方法可为独塔对称自锚式悬索桥的初步设计及其优化提供参考。

In the preliminary design stage of self-anchored suspension bridges, the design and calculation parameters need to be frequently modified, which leads to huge workload. There is an urgent need for a quick solution method so that designers can quickly understand how the bridge’s stress state changes with parameters.Based on the force characteristics of a single-tower symmetrical self-anchored suspension bridge, this paper proposed a simplified analytical method for solving internal forces and deformations based on the principle of Minimum Potential Energy. The self-anchored suspension bridge was divided into a stiffened beam system and a cable system, and the sling force under the dead load and the live load were respectively derived.According to the deformation coordination conditions of the stiffening beam end and the anchor point of the main cable along the bridge direction the horizontal component force of the main cable under the live load was obtained, and a simplified analytical solution of the internal force and deformation of the single-tower symmetrical self-anchored suspension bridge was derived from the condition. Taking the main span(150+150) m Jiuqiao Road self-anchored suspension bridge as an example, the method in this paper and the finite element method were used for comparative analysis. The results show that the calculation results of the two methods are in good agreement, and the distribution law is basically the same. The difference between the two methods of calculating vertical deflection and cable force is basically within 15%, which verifies the applicability of the simplified analytical solution. The method proposed in this paper can provide a reference for the design of a single-tower symmetrical self-anchored suspension bridge.