桥梁健康监测之传感器优化布置

讨论了以桥梁健康监测为目标的传感器优化配置问题,以模态置信度MAC矩阵最大非对角元为目标函数,提出基于模拟退火算法对传感器的配置进行组合优化,并给出算法中各种参数的选取原则和具体的操作步骤,算例表明,该方法应用于桥梁健康监测系统的传感器优化配置是切实可行的。     

Optimal sensor placement for structural health monitoring based on multiple optimization strategies

Careful selection and placement of sensors are the critical issue in the construction and implementation of an effective structural health monitoring system. A hybrid method termed the optimal sensor placement strategy (OSPS) based on multiple optimization methods is proposed in this paper. The initial sensor placement is firstly obtained by the QR factorization. Then, using the minimization of the off‐diagonal elements in the modal assurance criterion matrix as a measure of the utility of a sensor configuration, the quantity of the sensors is determined by the forward and backward sequential sensor placement algorithm together. Finally, the locations of the sensor are determined by the dual‐structure coding‐based generalized genetic algorithm (GGA). Taking the scientific calculation software matlab (MathWorks, Natick, MA, USA) as a platform, an OSPS toolbox, which is working as a black box, is developed based on the command‐line compiling and graphical user interface‐aided graphical interface design. The characteristic and operation method of the toolbox are introduced in detail, and the scheme selection of the OSP is carried out on the world's tallest TV tower (Guangzhou New TV Tower) based on the developed toolbox. The results indicate that the proposed method is effective and the software package has a friendly interface, plenty of functions, good expansibility and is easy to operate, which can be easily applied in practical engineering. Copyright © 2011 John Wiley & Sons, Ltd.     

结构健康监测中基于多重优化策略的传感器布置方法

如何在满足测试要求的前提下确定所需传感器的数目并优化其布设位置,已成为结构健康监测中亟待解决的问题。提出一种基于多重优化策略的传感器分步布设方法,首先以模态向量矩阵列主元正交三角分解得到传感器的初始布设位置;然后以模态置信度矩阵的最大非对角元为目标函数,采用逐步累积法,逐步增加可降低此初始布置模态置信度矩阵非对角元的传感器测点,并考虑非对角元均值的变化幅度,确定所需传感器的数量;最后通过基于二重结构编码的广义遗传算法优化传感器的布设位置。以600m高的广州新电视塔为例,分析了传感器优化布置方案,发现对于刚度有突变的结构（如电视塔的塔身和天线）,应对两者分开考虑传感器的布设。     

基于变形的城市桥梁健康监测系统初探

国内外不断发生的桥梁跨塌事故,引起人们对桥梁健康监测的日益重视。大跨径桥梁健康监测系统通常大而全且成本高昂,探索研究适合城市桥梁的健康监测系统具有一定的理论价值和现实意义。本文基于某城市桥梁的变形监测和定期检测,尝试提出基于变形的城市桥梁健康监测系统,工程实践表明,该系统操作方便,投资少,能及时进行桥梁安全与预警,可供目前广泛开展的城市桥梁健康状态评估参考借鉴。     

Optimization of bridge maintenance strategies based on structural health monitoring information

Highway bridges are subjected to strength degradation processes. Under budget constraints, it is important to determine the best maintenance strategies. Optimized strategies, based on prediction models, are already considered for the maintenance and operation of highway bridges. Prediction models are updated both in space and time by using non-destructive testing methods. Nevertheless, there is an urgent need for the efficient inclusion of structural health monitoring (SHM) data in structural assessment and prediction models. Indeed, SHM allows keeping strength degradation processes under control and should be included in life-cycle cost models. The lifetime reliability of structures is characterized by survivor functions. The SHM data enable to update the probability density function of time to failure through a Bayesian process. The aim of this paper is threefold: (a) to include SHM data in a bridge life-cycle cost analysis, (b) to determine optimal maintenance strategies based on monitoring information, and (c) to show the benefits of SHM. Optimal strategies are determined considering the cases without and with including monitoring results; the benefit of monitoring is then highlighted. The proposed concepts are applied to the I-39 Northbound Bridge over the Wisconsin River in Wisconsin, USA. A monitoring program of that bridge was performed by the ATLSS Engineering Research Center at Lehigh University.     

基于传感器网络的桥梁健康监测系统的研究与设计

本文主要通过传感器网络技术,将温度传感器、应变传感器、位移传感器等与动态称重系统进行系统集成,完成了对桥梁结构的安全监测,及时发现桥梁损伤,为桥梁维护管理提供技术依据,辅助桥梁日常交通管理,确保了桥梁的安全运营。本文主要对系统的整体架构、传感器网络系统、数据采集系统及软件系统的设计进行详尽的阐述。本文的论述,给桥梁工程领域提供了很好的健康监测应用案例,对从事该领域的工程技术人员具有重要的参考意义。     

Investigation of strain-sensing materials based on EM surface wave propagation for steel bridge health monitoring

This paper describes the exploration of a sensor concept for use in structural health monitoring. The sensor is based on the principle of electromagnetic (EM) surface wave propagation, and consists of a thin-layer of wave-guiding media attached to a metal base (e.g., steel bridge elements) and an EM wave emitter and receiver. Targeting at a low-cost and practical solution, various dielectric materials that facilitate EM wave propagation were examined. Low-density polyethylene was determined to have the most suitable dielectric properties and was selected for laboratory tests using tension coupon specimens. The tests of steel coupons with a low-density polyethylene strip indicated that the parameters of an EM wave (e.g., amplitude and phase) changed as the coupon specimens deformed. Therefore, the proposed sensor concept based on EM surface wave propagation can be a viable option for monitoring steel bridges.     

Long-term bridge health monitoring and performance assessment based on a Bayesian approach

This study presents a damage detection approach for the long-term health monitoring of bridge structures. The Bayesian approach comprising both Bayesian regression and Bayesian hypothesis testing is proposed to detect the structural changes in an in-service seven-span steel plate girder bridge with Gerber system. Both temperature and vehicle weight effects are accounted in the analysis. The acceleration responses at four points of the bridge span are utilised in this investigation. The data covering three different time periods are used in the bridge health monitoring (BHM). Regression analyses showed that the autoregressive exogenous model considering both temperature and vehicle weight effects has the best performance. The Bayesian factor is found to be a sensitive damage indicator in the BHM. The Bayesian approach can provide updated information in the real-time monitoring of bridge structures. The information provided from the Bayesian approach is convenient and easy to handle compared to the traditional approaches. The applicability of this approach is also validated in a case study where artificially generated damage data is added to the observation data.     

桥梁健康监测技术研究综述

本文介绍了桥梁健康监测的基本含义、研究开发的紧迫性和意义,综述了其研究现状、存在的问题,并对进一步的研究进行了展望。     

大型桥梁健康监测研究动态与发展趋势

大型桥梁健康监测是近些年来的研究热点之一。本文首先阐述了桥梁健康监测的内涵及意义,对健康监测系统的组成做了总结,然后从传感器的优化布设、信号处理与信息提取技术、损伤识别技术和安全评估方面对研究现状做了综述,最后针对目前存在的问题指出了未来的研究方向。     

基于健康监测系统的连续刚构桥模态识别技术研究

以一座实际连续刚构桥为例,利用为其架设的健康监测系统,对桥梁结构模态识别技术(FDD法)的应用进行了研究,并采用FDD法对该桥的模态信息进行了识别,结果表明:桥梁结构刚度较大,安全储备较高并且结构状态良好。     

基于遗传算法与神经网络的桥梁结构健康监测系统研究初探

在前人研究工作的基础上，根据遗传算法和神经网络在处理复杂非线性问题时的各自特点，分别将其用于桥梁结构健康监测系统的不同部分，提出了建立基于遗传算法与神经网络的桥梁结构健康监测系统的基本设想。由于该项研究工作刚刚起步，文中的有些部分已经经过试验验证，而有些部分则尚处于理论研究阶段，需通过试验进一步证实。     

Structural health monitoring of innovative bridge decks

For more than a century, important civil engineering structures such as bridges, high-rise buildings, dams and marine platforms have contained iron or steel as the reinforcement for concrete or wood. The useful lives of such structures have often been severely limited by the corrosion of this ferrous component. Much thought has been given in recent years to constructing structures that are lighter, stronger and non-corrosive. These innovative structures are new and for these to be accepted by the engineering community monitoring is mandatory. ISIS Canada has been developing such structures and monitoring them. In this paper, innovative bridge decks that have been implemented are described.     

广州黄埔大桥南汊桥健康监测方案

采用有限元通用程序ANSYS对该桥进行静力与动力分析确定传感器的布设位置，并依据计算的前20阶动力特性结果，采用遗传算法（GA）进行传感器的优化布设，选用精度较高的光纤光栅传感器，能够满足对桥梁长期监测的需要。     

桃夭门大桥结构健康监测传感器布点设计

通过对桃夭门大桥结构特点、风险特征及理论计算的分析,结合交通运输部的《公路桥梁结构安全监测系统技术规程》推荐,探讨了桃夭门大桥结构健康监测系统的主要监测内容及有代表性的测点设计方案。通过具体的工程应用实例,阐述了斜拉桥结构健康监测系统设计的一般方法,为类似的工程提供借鉴。     

公路桥梁健康监测技术应用

公路桥梁在我国交通运输中占据重要的部分,其结构特性及工作状态需要符合设计标准和使用要求,才能保证日常的安全运营。通过对公路桥梁的安全状态进行健康监测,利用知物云在线监测平台进行施工期和运行期的实时数据安全预警监测,以及时有效的评价工程的质量、安全情况。     

基于WSN的农业大棚智能环境监控系统研究

文章研究了基于WSN的农业大棚环境监控系统,分别从环境监控系统的硬件设计、软件设计以及系统优化几个方面进行了分析和研究。以保定地区草莓种植基地作为测试环境,对本系统进行了为期3个月的测试。实验结果表明,本系统能够实时、准确地采集环境信息。     

南昌新八一大桥健康监测预警指标计算分析

为了保证桥梁健康监测系统的有效性和及时性,给桥梁管理者提供维修及加固的依据,以南昌市新八一大桥为工程背景,在有限元数值模拟结合传感器监测数据的基础上,建立了多指标并行预警的结构预警体系,阐述了预警指标、预警阈值和预警流程,并重点对索力、关键部位应力和挠度、疲劳车辆荷载、固有频率变化率等预警指标进行了计算分析。应用结果表明,在当前荷载作用下新八一大桥的各项预警指标的结果都正常,满足使用要求。     

BIM在桥梁健康监测中的应用研究

结合具体工程实例,基于BIM二次开发技术,开发了桥梁健康监测的附加模块,可以实现风速、变形、应力等信息的可视化展示,可以为桥梁在健康监测中的应用提供参考。     

Integration of structural health monitoring in a system performance based life-cycle bridge management framework

In this paper, an approach for integrating the information obtained from structural health monitoring in a life-cycle bridge management framework is proposed. The framework is developed on the basis of life-cycle system performance concepts that are also presented in this paper. The performance of the bridge is quantified by incorporating prior knowledge and information obtained from structural health monitoring using Bayesian updating concepts. This performance is predicted in the future using extreme value statistics. Advanced modelling tools and techniques are used for the lifetime reliability computations, including incremental nonlinear finite element analyses, quadratic response surface modelling using design of experiments concepts, and Latin hypercube sampling, among other techniques. The methodology is illustrated on an existing bridge in the state of Wisconsin.