混凝土收缩徐变效应对矮塔斜拉桥索力的影响

Effect of Concrete Shrinkage and Creep Effection on the Cable Force of Extradosed Cable-stayed Bridge

矮塔斜拉桥是介于斜拉桥和连续梁桥(刚构)之间的过度性桥梁,收缩徐变通过改变主梁竖向位移,影响拉索伸长量大小,从而改变拉索内力。选取了中国、欧洲、美国、日本规范推荐使用的混凝土收缩徐变六种常用模型,对云南境内一座在建的矮塔斜拉桥进行建模分析。研究发现由于收缩徐变效应的影响,在运营阶段斜拉索索力都有不同程度的减小,各国模型的计算差异较明显,中国现行的04桥规的计算结果并不是所有规范中最不利的情况,建议运营阶段适当提高索力的安全系数。

Extradosed Cable-stayed Bridge is a transitional bridge between cable-stayed bridge and continuous girder bridge.Shrinkage and creeping of concrete by changing the vertical displacement of girder influences the size of elongation and changes the cable force.This article selects six kinds of com-monly used concrete shrinkage and creeping models that have been recommended by China,Europe,the United States,Japan specification to analyse extradosed Cable-stayed Bridge under construction located in Yunnan province.According to research,we can know that because of the influence of shrinkage and creeping,the cable force of every staye cable has reduced in different degrees in the operational stage. The differences between the calculation of all models are obvious.The cable stay tension calculation re-sults of specification of China in 2004 is not one of the most unfavorable situation,so this article suggest that we should appropriatly enhance the safety coefficient of the cable force in the operational stage.