基于BOTDA-FBG智能钢绞线的预应力损失监测  

Experimental investigation of prestress loss in PC beams based on BOTDA /FBG smart steel strands

作　　者：兰春光[1,2] 刘航[1] 周智[3] 

机构地区：[1]北京市建筑工程研究院有限责任公司,北京100039 [2]北京交通大学,北京100081 [3]大连理工大学,辽宁大连116024

出　　处：《土木工程学报》2013年第9期55-61,共7页China Civil Engineering Journal

基　　金：国家自然科学基金(50978079);北京市博士后工作经费(2013zz-95)

摘　　要：预应力筋作为预应力构件中的关键受力部位,其受力状态和现存预应力的大小是评估预应力构件安全性的主要指标。传统的预应力损失监测传感器存在着长期耐久性和稳定性差、信号传输距离短、不能绝对测量、布设方式复杂等诸多不足,严重限制了其在实际工程中的应用。基于增强纤维光纤布里渊与光纤光栅(FRP-BOTDAOFBG)智能筋的特点,考虑钢绞线的工作环境,设计开发出一种新型的光纤布里渊与光纤光栅智能钢绞线结构。并将其与传统预应力损失监测用传感器一起布设到直线单筋预应力混凝土梁和直线多筋预应力混凝土梁中,分别采用智能钢绞线内的光纤光栅传感器和光纤布里渊分布式传感器对预应力筋的预应力损失进行监测,并与规范计算值和传统传感器的监测结果进行对比。研究结果表明,智能钢绞线的监测结果能够正确反映预应力损失开展的趋势,且与传统传感器的监测结果和规范计算值相吻合。该新型智能钢绞线具有工程布设简单、耐久性好、绝对测量和实时监测能力强等优点,适合于预应力混凝土结构预应力损失的监测需要。Prestress loss is critical to the safety of prestressed structures. Unfortunately, nowadays, there are no qualified techniques to treat with this issue due to the fact that monitoring sensors may not survive the harsh construction environments and the time-dependent service life of the large-span prestressed structures. In this study, a novel smart steel strand based on the technique of integrating the Brillouin with fiber Bragg gratings （FBG） signal was introduced. Two kinds of prestressed PC beams were used to verify the idea of monitoring prestress loss by using smart steel strands. The prestress loss data may be achieved by Brillouin and FBG sensors, respectively, and then the data were compared with those from conventional sensors. It was shown that the monitored data can reveal the entire process of prestress loss in the construction stage and service life, and the data agree well with those from the structural analysis and provide higher accuracy than the data from conventional sensors, indicating that such kind of smart steel strands may be conveniently used to monitor the prestressed reinforcement in prestressed concrete structures.

关 键 词：预应力损失 分布式布里渊技术 光纤布拉格光栅 智能钢绞线 

分 类 号：TU378[建筑科学—结构工程]