Research on virtual load test method for damaged continuous beam bridges based on modal flexibility
In order to quickly evaluate the bearing capacity and actual operating status of continuous beam bridges,a virtual load test method based on modal flexibility was proposed.Taking a 3-span continuous beam bridge of a certain actual project(40+40+40)m as the research object,numerical simulation methods were used for in-depth analysis.The elastic modulus of the main beam unit was reduced by 30%to simulate the bridge damage,and SSI modal parameter identification technology was used to identify the modal parameters of the damaged bridge under white noise excitation to construct the displacement flexibility matrix.A virtual load test plan was designed to predict the modal deflection of damaged bridge under the virtual load,and the structural verification coefficient was calculated.The results show that under environmental excitation,only 42 measuring points need to be arranged at the quarter point section of a 3-span continuous beam bridge to accurately identify the dynamic characteristic parameters of the continuous beam bridge;Only the first 6 modal parameters are needed to predict the modal deflection of key sections of continuous beam bridges under virtual load tests;The structural verification coefficients of the 3-span continuous beam bridge under unbalanced and medium load conditions are all greater than 1,indicating that the bearing capacity of the bridge does not meet the design requirements and requires timely maintenance.The virtual load test method based on modal flexibility has certain application potential in evaluating the actual bearing capacity of 3-span continuous beam bridges,can provide reliable technical support for engineering practice.
bridge and culvert engineeringenvironmental excitationmodal flexibility matrixmodal deflectionvirtual load test
国家科技期刊平台
NSTL
万方数据
