体外预应力在连续刚构桥中的应用

【作者】 林圣钧；

【导师】 顾安邦； 钟宁；

【作者基本信息】 重庆交通大学 ， 建筑与土木工程， 2007， 硕士

【摘要】 重庆市新滩綦江大桥(75+130+75m连续刚构桥)是西部开发省际公路通道重庆绕城高速公路南段上一座跨越綦江的大桥,也是交通部西部建设科技项目体外预应力桥梁设计施工技术研究的一个依托工程,是国内首次将体外预应力技术应用到大跨连续刚构并实施的桥梁工程。本论文以新滩綦江大桥右幅体外预应力桥作为背景工程,通过制定对比研究对象,确定与左幅桥的全体内预应力桥梁进行对比,在制定的以一期体内预应力筋保证施工,二期体外预应力筋保证使用,以便充分发挥体外预应力的优点的思想下,从体内预应力筋的用量到线型,到体外预应力筋的用量和线型的优化分析,最后到体外预应力技术中的关键部位如锚固点及转向点局部构造的分析,以确保设计成果的准确性。通过体外预应力在大跨连续刚构的实施,总结出体外预应力的施工工艺,以及施工中的重要点.通过总结新滩桥的体外预应力桥梁设计和施工经验,提出了体外预应力技术的应用过程中存在的问题和建议。相关的体外预应力桥梁设计技术研究的成果不仅直接支持和指导了依托工程的设计和施工,同时也为体外预应力技术在我国桥梁中的应用有很好参考和借鉴作用。更多还原

【Abstract】 With a three-continuous-span of 75+130+75m, the Qijiang rigid-frame bridge, crossing over Qijiang River in Chongqing, is financially supported by the Ministry of Communications of China, for the first time, with the external prestessing technology in practice.Two 16.75m-wide bridges, symmetrizing the transverse direction, constitute the Qijiang Bridge. One‘is designed with internal and external prestressing, whereas the other is internal, the results of them have been compared between two breadth bridges to gain the differences. The external prestressing bridge is studied in this thesis. The external prestressing tendons are only for the stage after all internal prestressing tendons have been tensioned and grouted.The optimized aim for the internal and external is that all the internal prestressing only for the self-weight and the construction loads, while the external ones for all other loads. The prestressing alignment and the amount and the supererogatory tendons have been analyzed.The key location including turning zones, anchorage zones and the end of the sidespan for the external tendons replacement workplace have been designed and analyzed with finite element method, and the results have been introduced in. detail. After the optimized design and results estimated, the finial design and the achievement have been introduced.The internal prestressed bridge has three direction tendons: longitudinal, transverse and vertical while the external prestressed bridge no vertical one. They have a similar stress situation, for the optimized external prestressing could provid more effective shear resistance and flexural capacity, although the total weight of all the longitudinal prestressing tondons is smaller than the internal prestressing bridge. Being no vertical tendons, high quality concrete can be obtained and more tendons can be saved.The design results of this bridge prove that more labor and finance could be saved for the optimal external tendons with the special rate to internal tendons. More effective structure behaviors, less amount of tendons, higher quality concrete and shorter construction time could be expected.更多还原