Research On Dynamic Performance Of Bridge Structure Based On GPS-RTK Technology And Vehicle-bridge Coupled Vibration Analysis

The bridge structure is an important part of the national municipal infrastructure construction.At present,the number and scale of bridge structure in China are at the forefront of the world.During the operation period,the bridge structure is affected by various complicated factors such as the surrounding environment,vehicle load,and aging of its own materials.This will cause excessive dynamic deformation and even damage,affecting the dynamic characteristics of the bridge structure itself.In order to analyze the dynamic characteristics of bridge structure under the influence of different factors,two aspects of the research are mainly carried out in this paper:(1)dynamic deformation monitoring method and dynamic characteristic analysis of actual bridge structure under environmental excitation,(2)dynamic response law and dynamic characteristic analysis of continuous beam bridge structure under moving vehicle load.The primary contents and achievements of the paper are presented as the following:(1)The application of GPS-RTK positioning measurement technology in the dynamic deformation monitoring of bridge structures is studied.In order to improve the measurement accuracy,a hybrid filter combining EMD filtering and Chebyshev filtering based on autocorrelation function is proposed,which is called AFEC hybrid filter.It was applied to the field deformation monitoring data processing of Fumin Bridge in Tianjin.It was shown that the dynamic displacement sequences of the bridge structure can be extracted effectively,which verifying the validity and accuracy of the AFEC hybrid filtering method in weakening the multipath error and random noise in the GPS-RTK measurement data.(2)The dynamic characteristics of the continuous beam bridge structure under environmental excitation are studied and solved by using the extended ARMA?RDT modal parameter time domain identification method.Firstly,the free vibration signal data is extracted from the test vibration response signal data by the extended random decrement method(RDT),and then it is used as the input data of the ARMA model time series method for parameter identification.The first five modal frequencies are accurately identified,validating the applicability and effectiveness of the extended ARMA?RDT modal parameter time domain identification method in practical engineering applications.(3)Based on the existing bridge structure damage simulation method,a new method for damage simulation of reinforced concrete bridge structures is proposed.Considering the damage conditions of the bridge structure into the factors affecting the vehicle-bridge coupled vibration response,a numerical simulation program for vehicle-bridge coupled vibration based on Matlab and Ansys was developed to perform numerical analysis on the dynamic response of a non-destructive or damaged continuous girder bridge under moving vehicle loads.The accuracy of the proposed damage simulation method is verified by comparing the results of numerical analysis with the test results of vehicle-bridge coupled vibration model tests.(4)In order to study the dynamic characteristics of the bridge structure under the action of moving vehicle loads,an M-HHT time-frequency analysis method was proposed to improve the existing defects of the traditional HHT method.The M-HHT method is applied to the time-frequency analysis of synthetic signals and the dynamic response analysis of vehicle-bridge coupled vibration response.The natural frequencies of the analyzed signals can be accurately extracted,indicating that the M-HHT time-frequency analysis method has strong applicability and accuracy.(5)The vibration response of non-destructive and damaged continuous beam bridges under the action of moving vehicle loads is studied.The vehicle-bridge coupled vibration indoor model test is carried out to construct the damage conditions of different levels of the bridge structure,and the dynamic response of the test is analyzed.The influence of factors such as vehicle speed,vehicle weight,road irregularity,and damage degree of bridge structure on the dynamic response of continuous girder bridges is revealed.The results show that the vehicle speed and the roughness of the road surface have a greater influence on the dynamic response of continuous girder bridges under the action of moving vehicles than other factors.