大体积混凝土结构长期应变监测系统

大体积混凝土结构长期应变监测系统是近年应用于建筑工程管理与维护的一项新技术,具有重要的工程价值。无线振弦传感器具有抗干扰强,精度高,传输距离远等特点,广泛应用于大体积混凝土结构中长期应变的测量。本文主要论述了大体积混凝土结构长期应变监测系统结构和无线振弦传感器工作原理,设计了振弦传感器内部的激振电路及测频电路,以及无线通讯模块,分析了无线振弦传感器的特性。无线的设计极大的方便了振弦传感器的使用,通过工程实际应用显示,本文设计的基于正弦传感器的大体积混凝土结构长期应变监测系统稳定、质量可靠、测量数据迅速准确。     

振弦传感技术的新进展及新型锚索测力计

扼要介绍在振弦传感技术方面的研究成果及其在大量程锚索测力计中的应用。研究成果包括高增益弱激发电路、新数学模型、高精度智能检测仪及间接测量式振弦锚索测力传感器。新型锚索测力计具有准确度高、重复性好、温度影响系数小、寿命长、长期稳定性好等优点,适用于混凝土预应力工程锚索测力及岩土工程加固锚索的张拉力监测。     

基于Zigbee的无线传感器网络在桥梁健康监测系统中的应用探究

桥梁的建设和维护是国家基础设施建设的重要组成部分,桥梁健康监测技术能有效的保证桥梁的安全运营,保障人民群众的生命财产安全。桥梁健康监测系统通过对桥梁结构状态的监测与分析,为桥梁在特殊气候、复杂交通环境下和桥梁结构状况异常时发布预警信号,为桥梁的管理、养护与维修提供科学的依据。目前国内外桥梁监测系统大多为有线网络系统,存在着网络安装布线成本高昂、设备移动和网络结构灵活性差、节点智能化程度低等问题。为此,本文提出并设计实现了基于Zigbee协议的无线传感器桥梁健康监测网络系统。与传统的桥梁监测系统相比该系统具有成本低、可靠性高、安装方便、维护更新费用低等优势。本文针对桥梁健康监测技术的发展现状和无线传感器网络技术的应用,阐述了无线传感器网络的结构、分层模型和关键技术,将Zigbee技术应用于桥梁健康监测的无线传感器网络。对TI的基于Zigbee2006标准的协议栈Z-Stack进行了剖析。设计了适用于桥梁健康监测的网络拓扑结构,结合系统监测指标,给出基于Zigbee桥梁健康监测系统总体方案。     

核电站筏基用振弦应变计失效分析与试验

振弦应变计常设置用于核电厂混凝土结构长期监测,近年来若干核电工程项目结构内,特别是筏基内振弦应变计出现频繁损坏,对核电站混凝土结构安全监测产生一定影响。本文从施工安装和技术参数两个方面分析故障可能原因,通过安装措施前后改进对比研究,首先排除了施工安装造成故障这一原因,再通过参考振弦应变计相关的国家标准和模拟筏基大体积混凝土浇筑内部温度工况,设计了系列对比试验和检测方案,对振弦应变计的各项技术参数进行验证,发现该振弦应变计稳定性和耐温性不满足标准要求,而耐温性不足最终导致其内部钢弦发生腐蚀破坏而失效,分析得到根本原因后采取针对性的技术和管理措施,可为后续核电站结构的振弦应变计选用和故障防范提供参考。     

SF—1型振弦测力仪的研制

ＳＦ－１型振弦测力仪是振弦式工程用测力传感器的配套仪器，是与传感器同期研制而在的。该仪器配合大吨位振弱测力传感器应用于工程中，直接测量工程量值，特别是在建筑顾应力工程中，直接读取工程量值，直观性了，利于现场评估。     

扭振应力测量装置标准化设计研究

标准化是进行产品开发、技术改造、确保产品质量以及提高产品市场竞争力的重要途径。目前,尚无无线扭振应力测量装置产品标准,故给该装置的设计带来一定的不确定性。本文在充分研究扭振测量原理、应用以及国内外相关电子产品规范基础上,提出了无线扭振应力测量装置标准化设计要求,基于此,设计开发了一套便携式无线扭振应力测量仪,对其原理和应用作了介绍。本文的论述,为无线扭振应力测量仪开发人员提供了重要的设计依据,对扭振应力测量工程人员具有重要的指导意义。     

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。     

光纤法珀传感器及其在桥梁应变监测中的应用

应变是反映桥梁健康状况的重要参数,将光纤法珀传感器埋入混凝土结构内部,作为桥梁应变的智能传感元件,它与光开关、光纤应变解调仪、计算机等组成应变测量系统,可以实现桥梁应变自动监测。目前,该系统已经安装在重庆大佛寺长江大桥上,监测数据表明光纤法珀传感器的稳定性和可靠性好,能够用于大桥应变的长期监测。     

提高振弦传感器工程监测精度的技术研究

介绍了振弦传感器的工作原理,以及在结构监测中影响其监测精度的因素。在这些因素里,既有生产工艺等因素带来的无法避免的误差以外,还有非工艺性误差。如在施工监控和结构健康监测时对振弦传感器的安装偏差、温度变化的影响以及选用不同数学模型来标定的传感器等,分别对这些因素进行分析,并给出修正的方法和建议。     

远程无线静力水准监测系统在城市立交桥健康监测中的应用

为了解决目前静力水准仪在桥梁变形监测中存在施工难、数据反馈不及时、自动化性能差、施工速度慢等缺点,提出采用一套远程无线静力水准监测系统对桥梁进行自动化监测。本文着重介绍了远程无线静力水准监测系统中硬件设备设计,其提高了远程无线静力水准监测系统在工程现场施工、安装与调试的便捷性。通过对某立交桥监测数据进行分析,可说明本文提出的远程无线静力水准监测系统具有精度高、稳定性强等特点,在桥梁变形监测领域具有实用价值。     

A preliminary research on wireless cantilever beam vibration sensor in bridge health monitoring

According to specific bridge environment, optimal design piezoelectric cantilever beam structure by using results of theoretical calculations and simulation, verify natural frequencies of piezoelectric cantilever beam and production ability of data by experiment, thus formed a complete set of design method of piezoelectric cantilever beam. Considering natural frequency of vibration and intensity of the beam body, design a new type of piezoelectric cantilever beam structure. Paper analyzes the principle of sensor data acquisition and transmission, design a hardware integration system include signal conversion module, microcontroller module and wireless transmission module, test local read and wireless transmission for the combination structure of cantilever beam and data collection card, experimental verification of the radio piezoelectric vibrating cantilever vibration response is intact, the beam produced signal by vibration, acquisition card converts and wireless transmit data, this proved a good and intuitive linear response in simulation of bridge vibration test. Finally, the paper designed a kind of new wireless sensor of vibration cantilever beam, suitable for small bridge health monitoring based on Internet of things.     

Wireless Monitoring of a Multispan Bridge Superstructure for Diagnostic Load Testing and System Identification

Abstract: This article focuses on the deployment of a wireless sensor system (WSS) developed at Clarkson University for structural monitoring purposes. The WSS is designed specifically for diagnostic bridge monitoring, providing independent conditioning for accelerometers, strain transducers, and temperature sensors in addition to high‐rate wireless data transmission and is capable of supporting large‐scale sensor arrays. A three‐span simply supported structure was subjected to diagnostic load testing as well as ambient vibration monitoring. A total of 90 wireless and several wired sensors, including accelerometers and strain transducers were used in the deployment. Strain measurements provided capacity and demand characteristics of the structure in the form of neutral axis locations, load distributions, and dynamic allowances which ultimately produced an inventory and operating load rating for the structure. Additionally, modal characteristics of the structure, including natural frequencies and mode shapes, were derived from measured accelerations and discussed briefly.     

桥梁健康无线监测系统

桥梁无线监测系统克服了传统的有线监测的造价高、抗干扰性差的缺点。介绍了无线监测的概念和基本构成,设计了一种桥梁监测无线数字传输系统并进行了应变测试实验。分析了该系统的自身供能方法,分析了振动供能,提出了一种无线监测压电陶瓷电源,进行了该电源能量的理论分析,分析了两种电源的应用场合,为桥梁无线监测系统的设计应用提供了参考。     

基于桥梁健康监测的振动传感器

提出一种基于桥梁监测的光纤光栅振动传感器的设计方法。监测系统是基于测量压力啁啾的光纤布拉格光栅(FBG)反射带宽和反射光功率达到实时监控的目的。该传感器是由单根FBG组成,为了模拟真实桥梁振动情况,使用简支梁模拟桥梁。将单根FBG斜向粘贴在简支梁侧面上进行模拟试验,梁的上表面中间粘贴偏心轮来产生振动。振动将作用到简支梁上造成梁弯曲。梁弯曲时,在不同厚度层上产生呈梯度分布的应变,进而引起FBG的啁啾效应,造成FBG带宽发生变化。试验结果将电阻应变片和基于FBG的振动传感器进行对比。由于FBG对反射带宽和光功率温度不敏感,传感测量完全避开了温度的交叉敏感效应。该传感器可以广泛应用于桥梁的健康监测中,具有实时性及成本低等优点。     

F-P光纤传感器在桥梁台后结构试验中的研究

分析了F-P光纤传感器的基本工作原理,利用F-P光纤传感器对桥台后结构应变进行了短期监测,并与钢弦应变计的监测结果进行了对比,分析表明:F-P光纤传感器成活率高,可信性高。     

Long-term performance assessment of the Telegraph Road Bridge using a permanent wireless monitoring system and automated statistical process control analytics

The purpose of this study is to advance wireless sensing technology for permanent installation in operational highway bridges for long-term automated health assessment. The work advances the design of a solar-powered wireless sensor network architecture that can be permanently deployed in harsh winter climates where limited solar energy and cold temperatures are normal operational conditions. To demonstrate the performance of the solar-powered wireless sensor network, it is installed on the multi-steel girder bridge carrying northbound I-275 traffic over Telegraph Road (Monroe, Michigan) in 2011; a unique design feature of the bridge is the use of pin and hanger connections to support the bridge main span. A dense network of strain gauges, accelerometers and thermometers are installed to acquire bridge responses of interest to the bridge manager including responses that would be affected by long-term bridge deterioration. The wireless monitoring system collects sensor data on a daily schedule and communicates the data to the Internet where it is stored in a curated data repository. Bridge response data in the repository are autonomously processed to extract truck load events using machine learning, compensate for environmental variations using nonlinear regression and to quantitatively assess anomalous bridge performance using statistical process control.     

伊犁河特大桥静动载试验分析与探讨

介绍了伊犁河特大桥成桥状态下评定大桥结构静动力特性的荷载试验,在静载试验应力应变的量测中,尝试用振弦式表面应交计替代电阻应变片,并比较两者间的效率和精度,对大桥的结构性能做出评价,并对荷载试验的发展提出建议。     

Vibration testing of a steel girder bridge using cabled and wireless sensors

Being able to significantly reduce system installation time and cost, wireless sensing technology has attracted much interest in the structural health monitoring (SHM) community. This paper reports the field application of a wireless sensing system on a 4-span highway bridge located in Wayne, New Jersey in the US. Bridge vibration due to traffic and ambient excitation is measured. To enhance the signal-to-noise ratio, a low-noise high-gain signal conditioning module is developed for the wireless sensing system. Nineteen wireless and nineteen cabled accelerometers are first installed along the sidewalk of two neighboring bridge spans. The performance of the wireless sensing system is compared with the high-precision cabled sensing system. In the next series of testing, 16 wireless accelerometers are installed under the deck of another bridge span, forming a 4 × 4 array. Operating deflection analysis is successfully conducted using the wireless measurement of traffic and ambient vibrations.