城市轻轨高架桥连续箱梁时效变形试验

Time-Dependent Deflection Analysis of Prestressed Concrete Continuous Box-Beam in Urban Rail Transit Line

结合北京地铁13号线八达岭高架桥中预应力混凝土高架桥连续箱梁的实桥变形观测试验,以试验数据回归分析了基于综合时效的梁体后期变形.分析结果表明:统计回归所得的时效变形系数,其早期值比按我国铁路规范及ACI(American Concrete Institute)规范修正式计算所得的徐变系数略偏大,终极系数却偏小,同类轻轨高架桥梁结构后期变形按规范设计有足够的安全保证,但应严格控制早期时效变形.所提出的回归分析方法可为轻轨桥梁后期变形的预测提供参考.

Time-dependent deflection site tests of a continuous box-girder beam in urban railway transit line in Beijing are presented. The analysis is carried out on the patterns of beam＇ s deflection after prestressing, which is based on the test data of general deflection deformation. The results demonstrate that in early stage after prestressing, the time-dependent deformation coefficient derived from the statistical regression analysis is greater than the creep coefficient calculated according to the Code and that of ACI. But it＇ s reverse in final period. The similar urban rail viaduct designed in compliance with the Code has sufficient safety. However, the early time-dependent deflection should be controlled strictly.