准分布FBG钢绞线对混凝土梁预应力损失的监测  

Prestress loss monitoring in concrete beams using quasi-distributed FBG sensors steel strands

作　　者：覃荷瑛[1,2] 雷静 汤鹏飞 罗伯光[1,2] QIN Heying;LEI Jing;TANG Pengfei;LUO Boguang(Guangxi Engineering Research Center of Intelligent Structural Material,Guilin University of Technology,Guilin 541004,China;Guangxi Key Laboratory of Geotechnical Mechanics and Engineering,Guilin University of Technology,Guilin 541004,China)

机构地区：[1]桂林理工大学广西壮族自治区智慧结构材料工程研究中心,广西桂林541004 [2]桂林理工大学岩土力学与工程重点实验室,广西桂林541004

出　　处：《铁道科学与工程学报》2023年第7期2740-2750,共11页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52068014);广西创新驱动发展专项(科学AA20302006);广西重大科技创新基地建设项目(2018-242-G02)。

摘　　要：预应力损失是预应力构件设计及张拉施工的关键参数,同时也决定构件服役时的受力状态。然而,目前沿构件全长的预应力损失分布基本是依据理论公式和工程经验获得,难以通过实测求证。针对这一难题,提出将多点准分布FBG耦合于混凝土梁中预应力钢绞线中心丝的技术,并进行实验,以探求预应力损失影响规律及其沿构件全长的分布。实验结果表明:相比准确率低、失效概率大的应变片,多点准分布FBG存活率为100%,监测数据有良好的线性度,可实现预应力损失及其分布的监测。FBG对短期预应力损失的监测值与规范推荐的理论值变化规律一致:离张拉端距离越大,σ′l1越大而σ′l2越小,但监测数据整体比规范值少2%~10%。孔道形状对短期预应力损失影响较大,对长期预应力损失影响较小:直线孔道梁中短期预应力损失占总损失的40%~50%,短期损失率约为6%,曲线型孔道梁中其值分别为70%~73%及13%;直线孔道梁中长期预应力损失占总损失的50%~60%,长期损失率约为8%,而曲线型孔道梁中其值分别为27%~30%及6%。对总预应力损失而言,直线型孔道各测点其值小于曲线型孔道,前者总损失率约为14%,短期和长期预应力损失各半,而后者总损失率约为19%,并以短期预应力损失为主。通过多点准分布FBG对预应力损失监测试验,为预应力构件的设计、张拉施工及受力分析提供试验参考和技术支持。Prestress loss is a key parameter in the design and tension construction of prestressed components,it also determines the stress state of components in service.However,the distribution of prestress loss along the length of the component is basically obtained according to theoretical formula and engineering experience,which is difficult to verify by actual measurement.To overcome this problem,this paper put forward the technology of coupling multi-point quasi-distributed FBG to the center wire of prestressed steel strand in concrete beams,and carried out experiments to explore the influence law of prestress loss and its distribution along the length of components.The experimental results are as follows.Compared with strain gauges with low accuracy and high failure probability,the survival rate of multi-point quasi-distributed FBG is 100%.The monitoring data have good linearity,which can realize the monitoring of prestress loss and its distribution.The monitoring value of shortterm prestress loss by FBG is consistent with the theoretical value recommended by the specification.The greater the distance from the tensile end,the greater ofσ′l1 and the smaller ofσ′l2,but the monitoring data are 2%~10%smaller than the standard value.The shape of the channel has a great influence on the short-term prestress loss,but has little influence on the long-term prestress loss.The short-term prestress loss accounts for 40%~50%of the total loss in the straight channel beam,while the short-term loss rate is about 6%.The values in the curved channel beam are 70%~73%and 13%,respectively.The long-term prestress loss accounts for 50%~60%of the total loss in the straight channel beam,while the long-term loss rate is about 8%.However the values in the curved channel beam are 27%~30%and 6%,respectively.For the total prestress loss,each measuring point in the linear channel is smaller than that in the curve channel.The total loss rate of the former is about 14%,in which the short-term and long-term prestress losses are equal.The total

关 键 词：FBG传感器 预应力钢绞线 预应力损失 监测 

分 类 号：TU375[建筑科学—结构工程]