部分斜拉桥悬灌施工小节段与大节段方案设计研究

Schematic design study of small sections and large sections of suspension irrigation construction of part of cablestayed bridges

针对部分斜拉桥主梁挂篮悬臂浇筑施工方法施工工期相对较长、工艺较复杂的特点,为缩短项目工期,以武荆段新沟汉北河特大桥(111+208+111)m部分斜拉桥为研究对象,提出大节段悬灌施工方法。采用有限元软件对小节段悬灌施工及大节段悬灌施工进行全面分析,主桥结构受力及抗震性能,建立局部实体模型分析索梁锚固、索塔锚固等重点部位受力,研究主梁运梁工况的结构优化设计,研究主梁的竖向残余徐变控制措施。结果表明:采用(111+208+111)m三跨连续部分斜拉预应力混凝土箱梁桥式,结构体系为塔梁固结、主梁支座体系,斜拉桥由5m的小节段改为9m的大节段悬灌施工是正确的,能有效提高施工效率,缩短项目工期,可为类似桥梁设计提供参考。

In view of the characteristics of the relatively long construction period and complex process of the cantilever pouring construction method of the hanging basket of the main girder of some cable-stayed bridges,in order to shorten the project duration,the construction method of large-segment suspension irrigation was proposed by taking the Xingou Hanbei River Bridge(111+208+111)m part of the cable-stayed bridge in Wujing Section as the research object.The finite element software analysis was used to comprehensively analyze the suspension irrigation construction of small sections and large sections,the stress and seismic performance of the main bridge structure,the local solid model was established to analyze the stress of key parts such as cable beam anchorage and cable tower anchorage,the structural optimization design of the main beam transportation beam working condition was studied,and the vertical residual creep control measures of the main beam were studied.The results show that the(111+208+111)m three-span continuous part cable-stayed prestressed concrete box girder bridge type,the structural system is the tower girder consolidation and the main beam support system,and the cable-stayed bridge is changed from a small section of 5m to a large section of 9m suspension irrigation construction is correct,which can effectively improve the construction efficiency,shorten the project duration,and provide a reference for the design of similar bridges.