先张法预制U形梁单端张拉预应力施工技术研究  

Research on the Single-End Prestressed Construction Technology of Prefabricated U-shaped Beam Pretensioned

作　　者：王鹏 李磊[2] 马磊[2] 陈轶鹏 龚陈冲 WANG Peng;LI Lei;MA Lei;CHEN Yipeng;GONG Chenchong(Nanjing Subway Construction Co.,Ltd.,Nanjing 210000,China;China Construction Eighth Bureau Third Construction Co.,Ltd.,Nanjing 210000,China;Beijing Urban Construction Design&Development Group Co.,Ltd.,Beijing 100000,China)

机构地区：[1]南京地铁建设有限责任公司,南京210000 [2]中建八局第三建设有限公司,南京210000 [3]北京城建设计发展集团股份有限公司,北京100000

出　　处：《现代交通技术》2020年第2期86-89,共4页Modern Transportation Technology

摘　　要：结合某轨道交通工程预制U形梁工程实例,采用一联多片式长线法,整体单端先张拉多根预应力钢绞线,一次张拉长度超过78 m,研究不同施工阶段梁体预应力的损失情况。研究结果表明:逐根单端先张拉预应力钢绞线至设计应力的15%,而后整体单端先张拉预应力钢绞线至设计应力的100%,混凝土浇筑60 d后,梁体预应力平均损失≤5%,应力及伸长值符合设计要求。根据研究结果,一联多片式长线先张法预制U形梁施工中,采用先逐根再整体的单端先张拉技术是稳定可行的。Combined with an example of a prefabricated U-beam project in a rail transit project,a single multi-piece long-line method is used to pull multiple pre-stressed steel strands at one end as a whole,and the length of one stretch exceeds 78 m.Then the loss of prestress in different stages is studied.The results show that the prestressed steel strands are first tensioned one by one to 15%of the design stress,and then the overall tensioned prestressed steel strands are used to 100%of the design stress.After 60 days of concrete placement,the prestress of the beam is averaged.The loss is≤5%,and the stress and elongation values meet the design requirements.According to the research results,it is proposed that in the construction of a prefabricated U-beam with a multi-piece long-line pre-tensioning method,the technique of pre-tensioning at the single end of the whole one-by-one is stable and reliable.

关 键 词：长线先张法 一联多片 单端张拉 预应力损失 

分 类 号：U24[交通运输工程—道路与铁道工程]