光纤传感器在土木工程健康监测中的发展与应用

结构健康监测系统的关键因素之一是其系统内部的传感元件.光纤传感器的出现并以其优于其他传感器的特点,已经成为结构健康监测系统的首选传感器.本文将简单综述两类光纤传感器——FBG传感器和基于布里渊散射分布式光纤传感器在土木工程健康监测中的发展和最新的应用状况,并对BOTDR测试系统提出改进方案,以实现对平面分布信息的传感.     

光纤光栅传感技术在水工结构监测中的应用研究

应用新型光纤光栅传感技术,结合常见水工混凝土结构物的结构特征,采用结构测试、损伤评估等理论,建立了结构健康监测体系,对新型光纤光栅传感器在水工结构健康监测中的应用进行了相关研究,以此解决水工结构监测系统实际应用存在的基本构架技术问题。     

混凝土结构埋入式光纤应变传感器的耐用性解决方案

埋入式光纤应变传感器在混凝土结构的健康监测中应用日益广泛,但其有效寿命远低于结构的使用寿命,不能实现对结构的全周期监测。基于可更换的思路,提出了一种新型的传感器设计方案,通过对老化的主要应变传感部件(光纤光栅、基底和传输光纤)进行更新来使应变监测得以长期连续进行,从而简便可靠地解决了埋入式光纤应变传感器的耐用性问题。     

无线传感器网络在桥梁健康监测中的应用

阐述了结构健康监测系统的基本概念和构成体系.通过无线传感器网络的建设,对桥梁结构进行静载试验和动载试验,利用静态测试数据的传感技术和实时动态监测的信号来对结构损伤部位进行分析,使无线传感器监测系统满足结构的健康监测要求.     

大佛寺长江大桥健康监测系统

介绍了大佛寺桥的健康监测系统,该健康监测系统由本地子系统和远程监测子系统构成。其中本地子系统包括:(1)光纤应变传感子系统,(2)挠度位移测量子系统,(3)温度传感子系统,(4)动力学测量子系统等四个传感子系统及本地控制和数据处理子系统:而远程监测子系统则包含通信与传输子系统以及远程服务器群等;监测结果通过Internet传送到远端的管理中心。介绍了静态参数监测系统的设计、实施,并给出了各传感子系统的部分监测结果。     

土木工程健康监测无线测试信号同步性研究(Ⅱ)

无线传感技术应用到土木工程结构健康监测系统中需解决的重要问题之一,是传感器在数据采集过程中的同步性问题。本文从时延误差的产生入手,用频域内的峰值拾取法(PP)和时域内的特征系统实现算法(ERA),通过理论分析和数值模型实验考察了不同算法识别的结构动力参数的精度以及对包含时延的测试数据的处理情况,以此来判断其对整体结构分析带来的误差,并针对不同的系统识别方法提出了处理意见。     

混凝土结构埋入式传感器的耐久性研究

埋入式传感器在混凝土结构的健康监测中应用日益广泛,但其有效寿命远低于结构的使用寿命,为了解决这一问题,尽管学者们对传感器的封装和保护方法做了很多研究和探讨,但是若不解决埋入式传感器的更换问题,对结构的全生命周期监测实际上是不可能的.本文介绍了作者最近完成的有关混凝土结构埋人式传感装置的新型专利技术,通过对老化的传感装置进行替换来使应变监测得以长期连续进行,从而简便可靠地解决了埋人式传感器的耐久性问题.为验证专利技术的可行性,设计了相关试验以证明其可行性和实用意义.本文所介绍的专利技术不仅可以实现传感器的替换,而且可以保证替换过程中的连续监测及替换后的测量精度.     

土木工程健康监测无线测试信号同步性研究(Ⅰ)

无线传感技术应用到土木工程结构健康监测系统中需解决的重要问题之一,是传感器在数据采集过程中的同步性问题.本文从时延误差的产生入手,用频域内的峰值拾取法(PP)和时域内的特征系统实现算法(ERA),通过理论分析和数值模型实验考察了不同算法识别的结构动力参数的精度以及对包含时延的测试数据的处理情况,以此来判断其对整体结构分析带来的误差,并针对不同的系统识别方法提出了处理意见.     

钢管混凝土拱桥吊杆损伤分布式识别

随着工程结构的日益大型化和复杂化,结构损伤检测时需要布置大量的传感器.传统的集中采集和处理的技术将难以胜任海量数据的处理要求.有利于降低成本,密集布置的无线智能传感器就成为大型结构健康监测系统的最佳选择.采用分布式损伤识别方法是密集布排的无线传感测试系统的必然要求.针对拱桥吊杆损伤的问题提出应用于无线传感网络的分布式识别技术.以一混凝土钢管拱桥为实验平台,松动吊杆端部锚具制造不同程度的松弛损伤,对损伤前后拱桥进行振动测试,按照网络拓扑情况,利用功率谱密度曲率差法进行损伤识别分析.结果表明:分布式损伤识别技术能够成功识别拱桥吊杆损伤,并且该方法可以应用到其他密集布排无线传感器的大型复杂结构的健康监测和检测中.     

光纤布拉格光栅传感器用于混凝土结构施工监测

采用与土木工程施工特点相适应的操作工艺与保护方法,将自行研制的光纤布拉格光栅(FBG)应变传感器与温度传感器埋入一幢5层钢筋混凝土结构的大楼中,用以监测该建筑在施工过程中梁、柱的应变与温度变化.研究结果表明,埋入的FBG传感器可以方便地监测施工过程中混凝土结构内部温度与应变的变化,为混凝土结构的健康监测提供依据;自行研制的FBG传感器传感性能良好,成活率高,寿命长,为基于FBG传感器长期的混凝土结构健康监测奠定了基础.     

斜拉桥结构健康监测系统的设计与实现(I):系统设计

结构智能健康监测愈来愈成为重大工程结构健康与安全的重要保障技术,也愈来愈成为重大工程结构损伤积累乃至灾害演变规律的重要研究手段。斜拉桥健康监测系统是由传感器子系统、数据采集与传输子系统、结构分析子系统和数据管理子系统组成的,不同系统的谐调运行需要通过系统集成技术来实现。首先从监测内容、等级和功能等方面研究健康监测系统的总体设计原则;然后,分局部监测变量和整体监测变量研究传感器的最优测点确定方法和原则,提出传感器的选型原则;提出数据采集系统的总线设计方法和方案,研究数据采集系统硬件和软件设计方法;提出数据传输系统的设计原则和方法;给出斜拉桥基于构件和基于结构体系的安全评定设计方法;提出斜拉桥施工监控、成桥试验、运营健康监测和养护管理四位一体系统的共享设计原则;提出系统集成技术的软件设计方法。     

结构健康监测中传感器布点优化的研究进展

传感器布点优化(OSP)关系到结构监测系统(SHM)所采集信息的准确性及可靠性,是结构模型修改、损伤识别、状态评估的基础,是SHM中一个至关重要及热点研究问题。从优化目标(即传感器布点准则)及优化算法的角度对目前SHM中OSP方法进行综述,最后提出了对此领域中需要进一步研究的几个问题。     

大跨缆索支承型桥梁健康监测与评估系统的设计研究

随着我国经济迅速发展,对于交通运输能力的要求不断提高,结构健康监测（Structural Health Monitoring,SHM）系统越来越成为大型桥梁运营、养护管理、安全评估与维护的重要技术支撑。本文针对目前国内外大跨桥梁结构健康监测系统中存在的问题,围绕“结构健康监测、日常养护检测系统、周期检测相结合,综合建立大跨桥梁结构状态识别与安全评估系统”的思想,主要就建立大跨缆索支承型桥梁结构健康监测系统中的问题进行了研究,提出了明确的系统的总体设计原则、构成以及功能目标,对系统设计与安全评估目标的关系问题进行了分析研究,阐述了监测项目选择、传感器子系统、数据采集与传输子系统、数据处理与控制子系统、结构状态识别与安全评估子系统的设计原则或思路。     

On the Value of Monitoring Information for the Structural Integrity and Risk Management

This article introduces an approach and framework for the quantification of the value of structural health monitoring (SHM) in the context of the structural risk and integrity management for systems. The quantification of the value of SHM builds upon the Bayesian decision and utility theory, which facilitates the assessment of the value of information associated with SHM. The principal approach for the quantification of the value of SHM is formulated by modeling the fundamental decision of performing SHM or not in conjunction with their expected utilities. The expected utilities are calculated accounting for the probabilistic performance of a system in conjunction with the associated structural integrity and risk management actions throughout the life cycle, the associated benefits, structural risks, and costs and when performing SHM, the SHM information, their probabilistic outcomes, and costs. The calculation of the expected utilities necessitates a comprehensive and rigorous modeling, which is introduced close to the original formulations and for which analysis characteristics and simplifications are described and derived. The framework provides the basis for the optimization of the structural risk and integrity management based on utility gains including or excluding SHM and inspection information. Studies of fatigue deteriorating structural systems and their characteristics (1) provide decision support for the performance of SHM, (2) explicate the influence of the structural component and system characteristics on the value of SHM, and (3) demonstrate how an integral optimization of SHM and inspection strategies for an efficient structural risk and integrity management can be performed.     

A wireless sensor system for structural health monitoring with guided ultrasonic waves and piezoelectric transducers

Piezoelectric transducers are widely used for structural health monitoring (SHM) applications. Low weight and small dimensions are only two of the several advantages of piezoelectric transducers. However, these advantages are weakened by using wired connections for supplying the piezoelectric transducers. Besides the additional weight, a long wire connection can have an influence on the measured capacitance. Due to the aforementioned disadvantages, researchers developed different wireless solutions for SHM applications in the last 10 years. In this paper, we present a wireless SHM system, which is designed for SHM applications with piezoelectric transducers and guided ultrasonic waves (GUW). The first part in this paper describes the different parts of the wireless SHM system. One novelty ofthe proposed wireless system is that every wireless signal-processing unit (SPU) in the network can be used for exciting the piezoelectric transducer and also for measuring the voltage signals coming from the piezoelectric transducer. Finally, the paper presents a laboratory test on an aluminium/hardfoam sandwich plate with a removable artificial defect to accurately assess the performance merits and weaknesses of the wireless sensor network.     

利用少量传感器信息与人工智能的桥梁结构安全监测新方法

分析了当前结构安全监测在工程应用中存在的诸多问题和挑战,提出应发展利用少量传感器信息及基于大数据与人工智能的安全监测新方法,来克服现有系统传感器繁多、造价昂贵、海量数据难以处理的问题。介绍了单测点信息的多维相空间方法和单传感器信息的重构相空间方法;在基于双传感器信息的移动互相关函数法基础上,提出了基于双传感器信息的移动传递熵方法;阐述了基于少量传感器信息的移动主成分分析法的物理意义及其工程应用的适用性和可行性。利用单传感器方法和移动主成分分析法,以及小波包能量法、二次协方差矩阵法对虎门大桥进行长达5年的安全监测。阐述了基于深度学习的结构安全监测人工智能方法及其发展概况,分析了基于结构动力学信息的深度学习方法及其巨大的应用潜力。在此基础上进一步思考了基于少量传感器和人工智能相结合的方法在结构安全监测应用中的发展思路。结果表明:单传感器信息的重构相空间方法更适用于实际工程;基于双传感器信息的移动互相关函数法和移动传递熵方法均能精确定位损伤;移动主成分分析法最适用于实际工程的实时监测。     

Improved visualization of infrastructure monitoring data using building information modeling

Abstract

With growing complex infrastructure, autonomous condition assessment of large-scale structures has garnered significant attention over the past few decades. Data-driven structural health monitoring (SHM) techniques offer valuable information of existing health of the structures, maintain the safety and their uninterrupted use under varied operational conditions by undertaking timely risk and hazard mitigation. Traditional approaches, however, are not enough to monitor a large amount of SHM data and conduct systematic decision making for future maintenance. In this article, building information modeling (BIM) is utilised as a promising computing environment and integrated digital representation platform of SHM that can organize and visualise a considerable amount of sensor data and subsequent structural health information over a prolonged period. A BIM-enabled platform is utilised to develop the proposed visualisation tool for a long-span bridge and enable automated sensor data inventory into the BIM environment. Such automated tool facilitates systematic maintenance and risk management, while avoiding manual errors resulting from visual inspection of the structures. The proposed method can be considered as a user-friendly and economic framework for condition assessment and disaster mitigation of structures from long-term monitored data.     

Analysis of the strain transfer in a new FBG sensor for Structural Health Monitoring

Structural Health Monitoring (SHM) is a topic of great interest in structural engineering due to the ageing of the built infrastructures and the growing use of innovative structural systems and construction materials. Although several sensing technologies have been developed for use in SHM systems, fiber optic sensors, especially Fiber Bragg grating sensors (FBGs), are now attracting much attention due to their advantages over other types of sensors.This paper presents a new FBG strain sensor with an unsymmetrical packaging configuration designed to be fixed to the surface of the monitored structure. A 3D Finite Element numerical analysis of the sensor, packaging and adhesive used to fix the system to the host structure was conducted to study the influence of (1) the thickness and mechanical properties of the adhesive, and (2) the configuration of the packaging on the accuracy of the sensor. The results obtained from the numerical models show that the strains measured by the proposed system and the actual strains in the host structure differ by less than 2.5% due to the fact that the packaging contains only one layer of composite material in an unsymmetrical configuration. The proposed design can thus be said to be an improvement compared to the typical configurations of optical fiber surface strain sensors.     

Structural Health Monitoring System for the Shandong Binzhou Yellow River Highway Bridge

Abstract:   Structural health monitoring (SHM) provides a useful tool for ensuring safety and detecting the evolution of damage and performance deterioration of civil infrastructures. A great number of civil infrastructures under construction can be used as test beds for SHM systems. The Binzhou Yellow River Highway Bridge is a cable-stayed bridge in Shandong Province, China. An SHM system has been implemented on this bridge during its construction for monitoring its health status and assessing its safety for long-term services. The system includes a sensor module, a data acquisition module, a wired and wireless data transmit module, a structural analysis module, a database module, and a warning module. It is integrated by using LabVIEW software and can be remotely operated via Internet. The database is available freely to all scientists and engineers in the SHM research area. This article introduces the deployment and functions of this system, and presents the measured responses of the bridge subjected to moving vehicle loads.