基于伺服式倾角仪的桥梁挠度和转角监测技术的研究

【作者】 何先龙；

【导师】 杨学山； George C. Lee；

【作者基本信息】 中国地震局工程力学研究所 ， 防灾减灾工程及防护工程， 2012， 博士

【摘要】 由于塌桥事故的不断出现，各国对桥梁健康监测逐步重视起来。桥梁挠度和转角是桥梁常规检测和健康监测的重要内容，是桥梁健康状态评估的重要指标。虽然现在存在多种测试桥梁动挠度的设备，但是都无法用来长期在线监测一些桥梁的动挠度，特别是横跨较宽江面或深峡谷的大跨度桥梁的动挠度。目前由于没有成熟的、高精度的转角仪器可测试梁端转角，主要是基于测试出的挠度来换算出梁端转角，存在较大误差。在此背景下，本论文研究基于伺服式倾角仪来实现在线同时监测桥梁的动挠度和梁端转角。为此本文主要做了以下几个方面的工作：1.分析了基于倾角仪监测桥梁动挠度和梁端转角的可行性本文对各种桥梁挠度和梁端转角测试技术从原理上进行了分析，指出了各种方法的不足与优势。基于倾角仪测试挠度的方法从原理上看，相比其它方法，可以同时测试挠度和转角，且不需要静态的参考点和安装方便等优点，可用于对桥梁的动挠度和梁端转角进行长期在线监测。2.建立了由转角计算梁式桥梁挠度的数学模型和分析了倾角仪的优化布置基于倾角仪测试挠度的方法是一种间接测试挠度的方法，因此需要基于所测试桥梁的结构特点建立相应数学模型来逼近桥梁的挠度曲线函数，然后基于若干测点的转角计算出所测跨的挠度。数学模型能否很好地逼近真实挠度曲线函数直接影响到此方法的测试精度。本文从下面三个准则出发来研究用倾角仪测试梁式桥梁的挠度时，倾角仪的优化布置和数学模型的建立：(1)使用更少的倾角仪；(2)重要位置的挠度计算结果误差要小于5%；(3)基于数学模型计算挠度的计算效率要高，能满足在线计算的要求。基于以上三条准则，本文通过对一座简支箱梁的有限元分析，提出了采用5台均匀布置的倾角仪和由简单的离散正交多项式函数组构成的数学模型1来测试梁式桥梁的挠度和转角的方法，即采用5台倾角仪分别布置在所测跨的两桥墩附近、L/4、L/2、3L/4处时，依后基于这5个测点的转角由数学模型1计算出所测试跨的挠度曲线。为了检验此方法的可靠性，本文通过对一座预应力混泥土连续箱梁主跨在不同受力情况的挠度和转角的分析，检验了用此方法测试连续箱梁的挠度也是可行的。3.建立了由转角计算复杂结构桥梁挠度的数学模型和分析了倾角仪的优化布置本文基于简单的离散正交正弦和余弦函数建立用于逼近复杂结构桥梁挠度曲线函数的数学模型2，推导了此数学模型的求解方法，然后通过对一座中承式拱桥和一座独塔式斜拉桥的有限元分析，检验了数学模型2的可靠性和分析了倾角仪的优化布置。4.综述了小波分析和小波提升分解理论本文概述了小波分析的基本理论和推导了小波提升分解步骤。由于传统小波分析需要在时域和频域进行大量的计算，无法满足工程上对小波在线分析的需求，而小波提升分解只在时域进行，提高了小波分析的计算效率，可满足对工程测试信号进行小波在线分析的要求。5.研究了如何基于小波提升分解从QY倾角仪输出信号里提取出有用的转角信号QY倾角仪是一种高精度的伺服式倾角仪，但是当动态荷载经过桥梁时，QY倾角仪既能感应到桥梁竖向转角，也能感应到桥梁的纵向振动加速度。因此，需要从QY倾角仪输出信号里消除纵向振动加速度信号，才能得到桥梁的竖向转角信号。本文提出采用小波提升分解技术来实现在线、快速地提取出竖向转角信号。6.通过实际桥梁挠度测试的对比实验来检验本文研究结果的可靠性为了在实际测试中检验本文建立的两个数学模型和转角信号提取方法的可靠性，本文首先基于研究结果开发出实物G01NET桥梁挠度测试和监测系统，然后采用此系统分别做了以下几个实验：(1)、简支梁的静态挠度测试对比实验；(2)、连续铁路桥梁的静态挠度测试对比实验；(3)、预应力混泥土简支箱梁的动态挠度测试对比实验；(4)、预应力混泥土连续箱梁的动态挠度测试对比实验；(5)、下承式拱桥的动态挠度测试实验。通过以上的几个实验，很好地在实际测试中检验了本文的研究结果的可靠性，表明了基于本文研究结果所开发的实物G01NET桥梁挠度测试和监测系统可用于实际挠度和转角的测试或监测中。更多还原

【Abstract】 People began to pay attention to the bridge health remote monitoring assome bridges broken down in recent years. The deflection and slope angle ofbridge are important part of bridge general measurement and health remotemonitoring. There are some equipments can measure dynamic deflection, butnone can be used to online-monitor dynamic deflection of some bridges for along time, especially some bridges crossing widen river or canyon. There arenot good equipments can be used to measure slope angle of Beam ends, sonormally according deflection to calculate slope angle of Beam ends. Thisway has big error. Under such background, this paper wants to research howto monitor deflection and slope angle online at the same time with servo-slopesensors. The results are summarized as following.1. Researched the feasibility of using slope sensors to monitor deflectionand slope angle of bridgesResearched some technology of bridge deflection and slope anglemeasurement equipments, and realize their advantages and disadvantages.Comparing with other deflection measurement equipments of principle, theway of using slope sensor to measure deflection and slope angle has someadvantages, such as can measure deflection and slope angle at the same time,do not need static reference point and easy to install and so on. So slopesensors can be used to monitor deflection and slope angle of kinds of bridgesonline and for a long time.2. Building up a mathematic model to calculate the deflection ofgirder-bridges basing on slope angle and researched the optimize-install ofslope sensorsBasing on slope sensors to measure deflection is an indirect deflectionmeasurement method, so there should build up a mathematic model tocalculate deflection with slope angle of some points. Whether mathematicmodel can close in upon the real deflection function of bridge would affect themeasure-results of this method. Research in this paper base on the followingthree rules to build up mathematic model and optimize slope sensorsinstallation:(1) Using few slope sensors;(2) The error should small than5%in some important measurementpoints of bridge;(3) Model should has high calculated efficiency, can meet the need ofcalculating deflection of bridge online. According these three rules, build a simply box-girder and analyze it bySAP2000software, then based on the analyzing results bring forward amathematic model to calculate deflection of bridge. In this model, somesimple discrete-orthogonal functions form the mathematic model, just needfive slope sensors install evenly on the girder. Then basing on these fivemeasurement slope angle and using this mathematic model to calculate thewhole deflection of girder. Research in this paper aims to verify the feasibilityof this mathematic model, building up a Prestress Concrete continuousbox-girder, and using this mathematic model to calculate the deflection underadding different force to girder. The calculate results show that using thismodel to calculate such bridge deflection can get accurate results.3. Building up a mathematic model to calculate the deflection of complexstructure bridges basing on slope angle and researched the optimize-install ofslope sensorsResearch in this paper uses some simple discrete-orthogonal sine andcosine functions to form a mathematic model to close in upon some deflectionfunction of complex structure bridges, mainly research how to solve theunknown parameters based on slope angle of some points of bridge. Thenbuilding up one arch bridge and cable-stayed bridge by SAP2000software toverify the feasibility of this mathematic model to calculate deflection andresearch how to optimize slope sensors installation when measure suchbridges. The results of analyze show that it is feasible using this model tocalculate the deflection of complex structure bridges with few number slopesensors.4. Review the theory of wavelet analyze and upgrade wavelet analyzeResearch in this paper aims to review the theory of wavelet analyze andthe steps of upgrade wavelet. Wavelet analyze need calculate in time domainand frequency domain causing it calculating slowly and can’t meet the need ofwavelet analyze online. But wavelet upgrade decomposition just finishes intime domain, and improves the calculation efficiency of wavelet analyze.Therefore, can use wavelet upgrade decomposition to analyze measurementsignal online.5. Research how to use wavelet upgrade decomposition to pick up theuseful slope angle signal from the output signal of QY slope sensorsQY slope sensor is a type of high accurate servo-slope sensor, but it canpick up vertical slope angle signal and portrait-accelerate signal. Therefore,portrait-accelerate signal is noise signal and should be eliminated from theoutput signal of QY slope sensor. Research in this paper put forward some rules to use wavelet upgrade decomposition to pick up the useful slope anglesignal online and automatically from the output signal of QY slope sensor.6. Verify the accurate and feasibility of research in this paper by someexperiments on some typical bridgesResearch in this paper do several typical deflection measure experimentson some bridges with the G01NET bridge deflection measurement andmonitoring system which is the production of this paper:(1) The static deflection comparing measurement on simple Beam.(2) The static deflection comparing measurement on continuous railwaygirder-bridges.(3) The dynamic deflection comparing measurement on prestressconcrete simple box-girder-bridges.(4) The dynamic deflection comparing measurement on prestressconcrete continuous box-girder-bridges.(5) The dynamic deflection measurement on arch bridges.The results of these experiments show that the research results in thispaper are feasible and G01NET bridge deflection measurement andmonitoring system can get accurate results of bridge deflection. These alsoshow that G01NET bridge deflection measurement and monitoring system canbe used to monitor the deflection and slope angle of kinds of bridges.更多还原