大跨径预应力混凝土梁桥长期挠度控制分析

王法武，石雪飞

（同济大学桥梁工程系，上海，200092）

摘要：目前国内大跨径预应力混凝土梁桥存在的主要病害是跨中下挠过大和箱梁梁体裂缝。本文对跨中下挠过大的主要原因进行了分析，介绍了施工控制中线形控制的方法，然后用恒载零弯矩理论给一座已建的95+160+95m连续刚构桥重新配置预应力束，并对原设计和恒载零弯矩配束从内力、位移、预应力筋用量三方面作一比较，最后提出了控制跨中下挠过大的一些措施。

关键词：大跨径梁桥，跨中下挠，长期挠度控制，恒载零弯矩

      Study on Long-term Deflection Control of Large Span Prestressed     Concrete Girder Bridge

WANG Fa-wu, SHI Xue-fei

Abstract: At present, main problems of large span prestressed concrete girder bridges in our country are excessive midspan lag and cracks in box girder. In the paper, main causes of excessive midspan lag are analysed, and line control method during construction is introduced. Then prestress tendons of a continuous rigid frame bridge with a span of 95+160+95m is redesigned using zero bending moment method, and internal force, displacement, amount of prestress tendons are compared between two methods. In the end, some measures to control excessive midspan lag are given. 

Keywords: Large span girder bridge, Midspan sag, Long-term deflection control, Zero bending moment of dead load