Based Servo Inclinometer Bridge Deflections And Rotations Monitoring Technology Research

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.