锚下预应力衰减及拉脱法测试时机研究  

Study on the Attenuation Law of Effective Prestress under Anchorage and Test Timing of Lift-Off Method

作　　者：赖用满 谢发祥[2] 杨腾飞 Lai Yongman;Xie Faxiang;Yang Tengfei(Nanjing Public Infrastructure Construction Center,Nanjing Jiangsu 210019,China;College of Civil Engineering and Transportation,Hohai University,Nanjing Jiangsu 210098,China)

机构地区：[1]南京市公共工程建设中心,江苏南京210019 [2]河海大学土木与交通学院,江苏南京210098

出　　处：《城市建筑》2021年第35期163-166,共4页Urbanism and Architecture

基　　金：江苏省自然科学基金项目(BK2012412)。

摘　　要：拉脱法是检测后张法锚下预应力的有效方法。由于预应力筋放张后衰减明显,为提高预应力检测精度,需要分析导致预应力损失的不同因素的时变特征。本研究采用足尺梁实测的方法,获得了不同时间段内的预应力损失,采用相应的数学模型、实现温度、钢绞线松弛、混凝土收缩、徐变等影响因素的分离。利用获得的不同影响因素的解析模型,建立有效预应力衰减的时变模型,同时找到了48h内有效预应力相对稳定的测试时机。论文研究成果对衰减规律和拉脱法检测精度的提高有着重要的工程实践意义。The lift-off method is an effective way to detect prestress under post-tensioned anchorage.Due to the obvious attenuation of prestressed tendons after stretching,it is necessary to analyze the time-varying characteristics of different factors causing prestress loss in order to improve the accuracy of prestressing detection.In this paper,the prestress loss during different time periods was obtained by measuring the full-scale beam.The corresponding mathematical models were proposed to separate the influencing factors such as temperature,strand relaxation,concrete shrinkage,and creep.By using the analytical models of different influencing factors,the time-varying model of effective prestress attenuation was obtained,and the appropriate testing of relatively stable effective prestress within 48 hours was obtained.The research results of this paper have important engineering practice value for improving the attenuation law and the detection accuracy of the lift-off method.

关 键 词：拉脱法 检测 有效预应力 徐变 收缩 

分 类 号：TU921[建筑科学—建筑设计及理论]