A形混凝土中塔多塔悬索桥设计与拓展应用研究

为提升悬索桥的连续跨越能力,以瓯江北口大桥为背景,结合长江上已建成的3座三塔悬索桥,对三塔悬索桥的设计理念、设计要点、适用性等进行研究。在此基础上,对采用A形混凝土中塔的不同跨数和不同主跨跨度的多塔连跨悬索桥方案进行受力分析和拓展应用。研究发现:三塔悬索桥的性能关键在于中塔,中塔的刚度对桥梁整体刚度起决定性作用;采用增设全竖隔板的新型中主索鞍,主缆钢丝与鞍槽间名义摩擦系数可达到0.3;采用A形混凝土中塔的三塔悬索桥大幅提高了结构整体刚度和抗风稳定性能;A形混凝土中塔应用于多塔连跨悬索桥时,其主要力学指标变化幅度有限,影响主缆滑移的显著因素是恒载与活载的比率。

Research on Design and Extended Application of Multi-Tower Suspension Bridge with A-Shaped Concrete Middle Tower

In order to improve the continuous spanning capacity of suspension bridges, we studied the design concept, key points, and applicability of the three-tower suspension bridges by taking the Oujiang River North Estuary Bridge and the other three three-tower suspension bridges located in Changjiang River as research objects. On the basis of the research results above, we analyzed the mechanical behavior and application of the multi-tower suspension bridges adopting A-shaped concrete middle tower with different span numbers and different main spans. The results demonstrate that the performance of the three-tower suspension bridge depends on the middle tower, whose stiffness plays a decisive role in the overall stiffness of the bridge. The nominal friction coefficient between the main cable steel wire and the saddle groove can reach 0.3 by adding a new type of medium main cable saddle with full vertical diaphragms. The overall stiffness and wind stability of the three-tower suspension bridge can be greatly improved by using the A-shaped concrete middle tower. When the A-shaped concrete middle tower is used in multi-tower suspension bridges, the variation range of main static indicators is limited, and the significant factor affecting the slip of main cables is the ratio of dead load to live load.