Integrated Learning and Research:The Accelerated Construction Self-Sensing Project

To minimize travel delay impact,the US Department of Transportation(USDOT) has been pushing for Accelerated Construction(AC) techniques for public transportation construction.Contrast to traditional construction techniques,AC technology involves extensive applications of pre-fabricated components.This change in construction philosophy offers a great opportunity to introduce the concept of integrating full monitoring of structural construction/aging processes with AC technology via embedded sensors.The resulting structure can be quickly built and is able to self-sense health conditions throughout its service life.In order to introduce the concept and encourage synergistic learning,a joint course between Construction Management course in Engineering Technology(ET) department and Nondestructive Testing course in Civil Engineering(CE) department, has been developed with the course content designed to engage students to research on the Smart Monitoring of Accelerated Construction(SMAC ) in a two-stage(ET-CE-ET) project.This innovative approach generates synergies amongst students and encourages them to self-learn new techniques.

基于光纤光栅感测技术的桥梁挂篮施工期应力应变监测方法

针对桥梁内部应力与应变传统监测技术耐久性差、测量繁琐等技术不足,提出1种基于光纤光栅感测技术的桥梁挂篮施工结构健康监测方法。以跨常合高速分离式立交桥为研究对象,选取施工期活载作用下桥梁受力最不利截面,在桥墩处起步梁段的箱梁顶板、底板与腹板中心线交汇点植入光纤传感器监测其应力、应变,分析起步梁段箱梁在挂篮施工期的应力、应变的变化规律,评估桥梁挂篮施工期的内部结构健康状态。结果表明:提出的方法可用于监测桥梁内部受力变化,起步梁段顶板应力、应变增长主要受预应力张拉影响,底板应力、应变增大主要受混凝土浇筑影响;中跨合拢段箱梁浇筑后,中跨梁段不再呈现上拉下压现象;顶板应力、应变均在边跨合拢段前一个梁段预应力张拉后达到峰值,底板应力在边跨合拢段前一个梁段浇筑后达到峰值,而底板应变在边跨合拢段预应力张拉后达到峰值。建议桥梁挂篮施工过程中,应重点监测边跨合拢前一个梁段施工至施工结束这几个阶段的应力、应变变化。

基于DFOS的船闸水工结构监测研究

基于分布式光纤感测(DFOS)在大型工程结构监测方面的技术优势,将其应用于船闸水工结构的安全健康监测中,运用以布里渊光时域分析(BOTDA)和布拉格光纤光栅(FBG)应变感测技术对船闸闸首和闸室结构在施工中的应力、应变过程进行了监测;运用以光时域反射(OTDR)和拉曼散射光纤感测技术为原理的ROTDR系统对船闸闸首底板浇筑过程中混凝土水化热的释放进行了监测,并由此对应变监测结果进行了温度补偿。根据监测结果,综合分析了混凝土水化热释放过程和上部荷载双重作用下船闸闸首结构内部混凝土和钢筋的应力、应变过程,并验证了分布式光纤感测技术在船闸等大型水工结构施工安全监测中的可行性。