客运专线简支箱梁徐变发展研究

采用不同徐变计算模型对客运专线预应力箱梁终张拉完成后顶底板不同位置徐变应变进行了计算分析。在箱梁几个关键截面埋设钢弦式应变计,监测了梁体长期应变。长期监测结果表明,梁体终张拉完成后60d内徐变发展曲线斜率大,徐变增长迅速,60d后徐变增长速率明显放缓,150d后徐变发展趋于平稳。GL2000模型和CEB-FIP(1990)模型徐变计算结果在预应力作用初期均偏大,但长期徐变发展曲线与实测结果符合较好。对于徐变预测,在不同加载龄期合理采用不同的计算模型能够提高徐变预测的准确性。

Research on the Creep of Simply Supported Box Girder in Passenger Dedicated Line

Different creep computation models were used to analyze the creep of different position of top slab and bottom slab of prestressed box girder after final tensioning in passenger dedicated line.Vibrating wire strain gauges were embedded in several key sections to monitor the long-term strain of concrete.Long-term monitoring result shows a big slope of creep growth curve in the first 60 days after the final tensioning.Creep grows rapidly at this period.The creep growth rate slows down obviously after 60 days and tends to stable after 150 days.Both the GL2000 model and CEB-FIP(1990)model calculate a bigger creep result than experimental monitoring values in early stage after the final tensioning,but the two models present a better result in long term.For accurate creep prediction,it is reasonable to use different computation models in different load age.