金马大桥主塔直束预应力筋设计技术与研究分析

斜拉桥塔柱是主要的受力构件之一,因为塔柱拉索区有斜拉索巨大的拉力存在,所以要用预应力筋加强锚固区。广东金马大桥的主塔设计中采用有别于传统环型预应力束的加强锚固区的锚固方式,即采用精轧螺纹钢筋直束加强塔柱拉索锚固区的技术,这在国内特大跨径斜拉桥中是首次。本文分别就传统的U型环束加强方式和金马大桥采用的直束加强方式对该桥桥塔进行详尽的有限元模拟计算,从塔柱内力和预应力钢束的损失两个方面进行计算分析和比较。此外为了优化预应力筋的布束方式,进行了阶段塔柱光弹试验,对这种直束加强技术进行了验证,为同类型的大跨度斜拉桥的主塔设计提供一定的参考和借鉴。

Design Tech and Research Analysis on Straight Prestress Strengthening of Main Tower of Jin Ma Bridge

The main tower is one of the primary structure members in cable-stayed bridge.There is great tensile force in the anchorage zone.Tendon is needed to reinforce the anchorage zone.In the main tower design of Jin Ma Bridge,linear finish rolling deformed bar,which is different from traditional annular tendon,is for the first time to be used in China,to reinforce the anchorage zone of the main tower.Detailed FEM computation is done on U-shaped traditional annular tendon and # shaped linear tendon of Jin Ma bridge.Analysis and comparison are made in terms of the internal force and loss of prestress.To optimize the disposal of tendon,photoelastic test is done on the main tower.This tech is proved and can be reference for similar long-span cable-stayed bridge.