时效变形对城市轻轨高架桥二期施工的影响分析

Influence of Time-dependent Deflection on the Second Construction Stage of Urban Railway Transit Line

以北京城市轻轨线某预应力混凝土高架桥连续箱梁的实桥应变观测试验为基础．利用实验数据进行回归分析，阐述了梁体时效变形的发展规律及其对轻轨道路二期施工的影响,实验结果表明：以应变发展规律得出的时效变形系数在数值上能够很好地估算梁体的后期变形增量，合理安排二期施工时间，在该高架桥预应力筋张拉2～3个月后安装桥上轨道设施，梁体后期变形相对增量最大值约为3～4mm左右，可完全满足钢轨扣件调节量要求．本试验分析为轻轨桥梁时效变形预测及施工控制提供参考．

On the base of strain site tests of a continuous box-girder on urban railway transit line in Beijing,a statistical regress method was used to analyze the time-dependent law of deflection. The influence of time-dependent flexibility on the second construction stage of the viaduct was discussed. The coefficient extracted from time-dependent strains was effective to estimating the time-dependent defelection. We found that the time of second construction stage became a key factor to keep the flexibility increment in the range provided by the rail fastener. The results gave references of estimating the time-dependent deflection and controlling the construction phases.