斜拉桥索塔低回缩环向预应力锚固结构研究

Study of Low Retracting Ring Prestressed Anchorage Structure in Pylon of Cable-Stayed Bridge

为设计一种新型的斜拉桥索塔锚固区预应力锚固结构,避免采用常用环向预应力索塔锚固结构带来的局限性,在调查分析了已有研究成果的基础上,从锚固区环向预应力损失的原理出发研究减少预应力损失的措施,提出了新型的低回缩环向预应力锚固结构方案。以韩家沱长江特大桥索塔锚固区为研究对象,设计了索塔低回缩环向预应力锚固结构和U形环向预应力锚固结构,并对这2种方案的有效预应力及预应力作用下索塔锚固区混凝土应力进行计算,结果表明,采用低回缩环向预应力锚固结构可显著减少预应力损失且有效应力沿程分布均匀,索塔锚固区的混凝土应力分布也更加均匀。

To design a new type of the prestressed anchorage structure for anchorage zone in pylon of cable-stayed bridge and to avoid the limitations caused by utilization of the common ring prestressed anchorage structure in the pylon of the bridge, the related measures for reducing prestress loss were studied and a new type of the low retracting ring prestressed anchorage structure was developed on the basis of investigation and analysis of the existing research achievements and in accordance with the principle of ring prestress loss of the anchorage zone. By taking the an- chorage zone in the pylon of Hanjiatuo Chnagjiang River Bridge as the research object, the low retracting ring prestressed and the U-shape ring prestressed anchorage structures were designed and the effective prestress of the two types of the structures and the stress of concrete of the anchor- age zone in the pylon under the action of prestressing were calculated. The results of the calculation demonstrate that the utilization of the low retracting ring prestressed anchorage structure can significantly reduce the prestress loss, the distribution of the effective stress on path is uniform and the distribution of the stress of concrete of the anchorage zone in the pylon is still more uniform.