Abstract: In view of cracks in the webs and deflections in the middle of span widespreadly existing in the current large span continuous ridge-frame bridge,the Xitan Qijiang bridge has been taken as an example,and a new prestressing system——the internal and external prestressing technique has also been introduced.The right bridge is designed with internal and external prestressing,whereas the other one is designed with internal prestressing.The results of two bridgos have been compared to gain the differences in suffering.From aspects of controling ramp cracks,repressing deflections in the middle of span and economy,the advantages of the internal and external prestressing technique have been discussed.

Key words: external prestressing, continuous ridge-frame bridge, comparative analysis

摘要： 针对目前大跨度预应力连续刚构桥普遍出现的腹板开裂和跨中下挠的情况,以新滩綦江大桥为工程背景,介绍了一种新的配索体系——体内外混合配索。通过对左幅体内预应力桥和右幅体内外混合配索桥的有限元对比分析,总结出两幅桥的不同受力特点;并从控制斜裂缝的开展、抑制跨中下挠和经济性3方面,对体内外混合配索的优势进行了探讨。

关键词: 体外预应力, 连续刚构桥, 对比分析