Study On Bridge Deformation Monitoring Method And Experiment Based On FBG

China have a long history about bridges.Since ancient times,the bridge is an important part of the traffic,and is closely related to people's production and life.From construction to operation,the bridge is always affected by the natural environment and traffic load.These factors will cause serious damages to the bridge,which has a direct impact on the applicability and durability of the bridge.Serious damages of the bridge will cause serious impacts on people's life.Therefore,the correct understanding and analysis of the bridge disasters,and put forward reasonable and effective solutions have important economic value and social benefits.At present,some of the traditional bridges health monitoring has certain drawbacks,by vigorously research and exploration of experts and scholars,the Fiber Bragg Grating sensor in the field of bridge health monitoring,once found,it is soft,light with high accuracy and good stability,anti electromagnetic interference,anti falling performance for the majority of experts accepted.This paper will introduce the long-gauge Fiber Bragg Grating strain sensor,which will replace the traditional point type optical fiber Prague grating sensor.After repeated tests,we find long-gauge Fiber Bragg Grating strain sensor can accurately measure the structural response of the bridge structure.Based on this,this paper makes the following research on the long-gauge Fiber Bragg Grating strain sensing :(1)Firstly,the background and significance of this topic,and the development of long-gauge Fiber Bragg Grating strain sensing at home and abroad and some engineering examples at home and abroad are described;(2)Fiber Bragg Grating(FBG)introduced the framework design of health monitoring system,from the bridge to the classification,classification of monitoring system,and then to the monitoring content and principle of the formula classification and application.(3)The short distance sensor is developed to be a long distance sensor,and the length of the sensor is the most needed.The third chapter is the principle and a small experiment to illustrate the advantages of long distance sensor in use.(4)For a typical beam bridge the T beam monitoring test.Based on the 8 elements of the beam,the distribution mode of the parallel topology is used to lay the sensors in each unit.Based on the measurement of the curvature of the bridge,the deflectionmeasurement of the bridge is carried out.(5)Based on the number of units in the last chapter,the number of units is less,so do simulation.In the simulation,based on the experience and the actual situation,the standard distance of 0.1 meters,0.2 meters and 0.3 meters respectively.According to the structure of several experiments,it is concluded that,under normal circumstances,the shorter the distance is,the better it is,but it is guaranteed to cover the cracks.In the actual measurement,we can consider the use of different scales of sensors.