摘要
混凝土拱桥由于其结构特点和材料性能,运营后期不可避免会产生残余下挠变形,直接影响到结构受力和行车安全。以某一在建的铁路大跨度混凝土拱桥为对象,系统研究了3种典型施工方法(悬臂拼装法、悬臂浇筑法和劲性骨架法)的可行性,分析了不同工法对结构长期残余变形和受力的影响,获得了3种工法中采用劲性骨架法的结构长期残余变形最大;采用悬臂拼装法和悬臂浇筑法的结构,主要控制截面成桥后的应力发展趋势基本一致,且变化幅度基本相同,采用劲性骨架法施工的拱脚、L/4和拱顶截面后期应力明显降低。研究结果表明:采用劲性骨架方法形成的拱圈,由于顶、底板应力分布不均匀加剧了后期的残余变形;较短的工期会造成悬拼法成拱的结构后期残余变形较大,应适当延长混凝土节段预制时间;劲性骨架施工法由于骨架的存在使得混凝土的徐变内力进行重分布,混凝土受力减小。
Due to the structural characteristics and material properties of concrete arch bridges,residual deformation is inevitable in the later operation period,which directly affects the structural behavior and driving safety.In this paper,the feasibilities of three typical construction methods(cantilever assembling method,cantilever casting method and stiff-skeleton method)are systematically studied for a railway long-span concrete arch bridge under construction,and the influences of different construction methods on the long-term residual deformation and stress are analyzed.Of the three methods,the maximum long-term residual deformation is obtained by using the stiff-skeleton method.With cantilever assembling method and cantilever casting method,the development trends of residual stress for the main control section are basically the same,and the same is true for the changing amplitude.The stresses of arch foot,L/4 and the vault are significantly reduced in the later stage with the rigid skeleton method.The results show that the residual deformation of the arch ring formed by the stiff-skeleton method is aggravated due to the uneven distribution of stress on top and bottom.As shorter construction period will result in a larger residual deformation when cantilever assembling method is adopted,the precast time of concrete segment should be extended appropriately.Due to the existence of the skeleton in the stiff-skeleton method,redistribution of internal forces results in a reduction of the concrete stress.
作者
王业飞
杨国静
WANG Yefei;YANG Guojing(China Railway Signal&Communication Research&Design Institute Group Co.,Ltd.,Beijing 100160,China;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu 610031,China)
出处
《铁道标准设计》
北大核心
2021年第5期107-112,117,共7页
Railway Standard Design
基金
四川省科技计划项目(2018GZ0052)。
关键词
铁路桥
拱桥
残余变形
悬臂拼装法
悬臂浇筑法
劲性骨架法
railway bridge
arch bridge
residual deformation
cantilever assembling method
cantilever casting method
stiff-skeleton method
