摘要
有效监测后张法有黏结预应力结构在施工过程中产生的短期预应力损失大小是评估整个预应力结构安全性的重要手段。基于对现有预应力损失监测难题及预应力损失计算的理论分析,提出了光纤光栅自感知钢绞线短期预应力损失的监测技术。基于此技术,有效监测了直线及曲线孔道梁的短期预应力损失,并与应变片监测值及理论计算值进行比较。监测结果表明:直线孔道梁短期预应力损失率约10%σcon(σcon为张拉控制应力),曲线孔道梁短期预应力损失约24%σcon;对比理论计算值,应变片的误差最大接近10.01%,且同一测点处不同应变片最大差值接近10%,数据离散型较大,而光纤光栅监测到的梁内最终有效应力误差最大仅为4.60%,且在监测过程中始终保持良好的监测性能,可见光纤光栅传感器相比电阻应变片更适合体内预应力监测。
Effectively monitoring the short-term prestress loss of post tensioned bonded prestressed structure during construction is an important means to evaluate the safety of the entire prestressed structure.Based on the theoretical analysis of the problems existing in prestress loss monitoring and calculation of prestress loss,a fiber grating self-sensing monitoring technology for short-term prestress loss of steel strands was proposed.Based on the technology,the short-term prestress loss of straight and curved tunnel beams was effectively monitored and compared with the results of strain gauges and theoretical calculations.The monitoring results show that the short-term prestress loss rate of straight channel beams is about 10% σ_(con)(σ_(con) is the tension control stress),and the short-term prestress loss rate of curved channel beams is about 24% σ_(con).Compared with theoretical calculations,the maximum error of strain gauges is close to 10.01%,and the maximum difference value of different strain gauges at the same measuring point is close to 10%,with relatively high data discreteness.In addition,the maximum error of the ultimate effective stress detected by the fiber grating is only 4.60%,and it always maintains good monitoring performance during the monitoring process,It can be seen that the fiber grating sensor is more suitable for the monitoring of internal prestress than the resistance strain gauge.
作者
覃荷瑛
石家辉
徐辉华
QIN He-ying;SHI Jia-hui;XU Hui-hua(College of Civil Engineering and Architecture Guilin University of Technology, Guilin 541004, China;Department of Civil Engineering, Guangxi Polytechnic of Construction, Nanning 530007, China)
出处
《科学技术与工程》
北大核心
2021年第32期13906-13913,共8页
Science Technology and Engineering
基金
国家自然科学基金(51768014)
广西科技重大专项(桂科AA18118008)
广西重大科技创新基地建设(2018-242-G02)。
关键词
短期预应力损失
光纤光栅
内嵌式智能钢绞线
监测性能
short-term prestress loss
fiber bragg grating
embedded smart steel strand
monitoring performance
