Fusion Of Two Kinds Of Sensing Technology Of The Whole Bridge Strain Response Reconstruction Method

As the hub of regional connection,the safety of bridge structure affects the local economic development and social stability and prosperity,so it is imperative to carry out regular safety monitoring of bridge.the full bridge response monitoring can ensure the accuracy of system identification and the reliability of structure monitoring.However,in practical engineering,the number of sensors is limited and it is difficult to install sensors in some key positions of the structure.Structural responses are usually only available in a few positions of the structure,making it difficult to reliably evaluate the safety performance of the actual structure.Therefore,this paper proposes a full bridge strain response reconstruction method that combines the advantages of long gauge fiber grating sensors(FBG)and visual sensors to monitor the full bridge response.The research content and innovation of this paper are as follows:(1)An optimal sensor layout scheme is proposed.Firstly,under static load condition,distributed cameras are used to measure the displacement of the whole bridge to identify the damage information of each unit.Combined with the damage information identification results of each unit and the layout method and number of sensors,the visual sensor and strain sensor are rationally arranged to realize the purpose of monitoring the whole bridge.(2)A full bridge strain response reconstruction method combining two sensing technologies was studied.This method utilizes the advantages of long gauge fiber grating(FBG)sensing technology and visual sensing technology that can accurately collect structural strain and displacement responses,respectively.A limited long gauge FBG sensor was installed on the bridge beam to collect the strain response of the monitoring unit in real time,a visual sensor under the bridge to monitor the displacement response of the unit that does not cover strain sensor.Furthermore,by analyzing the complex mapping relationship between element displacement and strain,a transformation relationship between element displacement and strain is established.Finally,the effectiveness of the proposed strain reconstruction method is verified through finite element numerical simulation and laboratory model tests.(3)The effectiveness of the proposed strain reconstruction method is verified by finite element numerical simulation and laboratory model test.In numerical simulation verification,a variety of static load and dynamic load conditions were analyzed respectively to verify the effectiveness of the proposed method.In the experimental model,the validity of the method is verified by setting the conditions of no damage and damage.The numerical simulation and experimental results show that the proposed method can accurately identify the unit characteristic information,the structural response reconstruction accuracy meets the practical engineering requirements,and the monitoring of the whole bridge can be realized.