Bearing Capacity Assessment Of Reinforced Concrete Beam Bridges In Service Based On Detection Data

With the rapid development of social economy,transportation plays an increasingly important role.Bridge is an important part of the transportation system and it plays an indispensable role in road network traffic.However,the service time of reinforced concrete Bridge and the load gradually increase,which reduces the bearing capacity of the bridge and the safety performance of the bridge structure.This paper is based on the test data of a reinforced concrete simply supported t-beam bridge to analyze the bridge.And the paper establishes the resistance time-varying model which is based on the deterioration of structural material performance and it also establishes the load effect model which is based on the measured traffic flow to analyze its reliability by performance function.The main work of this paper is as follows:Based on the test procedure,an appropriate test plan is developed,and the bridge is subjected to non-destructive testing,visual inspection,dynamic and static load test,and the real technical status of the bridge is obtained through structural test data.Based on the design data,the Midas finite element software is used to simulate the bridge structure,and the sensitivity analysis of the parameters affecting the dynamic and static response of the structure is carried out.The model parameters are modified according to the actual technical conditions of the bridge,so that the modified model response tends to the measured response of the bridge.Based on the existing research results,the time-varying characteristics of concrete carbonation,steel corrosion and bond performance degradation are comprehensively analyzed.The structural resistance degradation model and statistical parameters in the literature are summarized,and the structural resistance time-varying model under multi-factors is established.Based on the measured traffic data of the WIM dynamic weighing system,the bridge vehicle load model is established and loaded onto the bridge model by the influence line principle to obtain the corresponding most unfavorable load effect distribution model.Based on this,the load effect extreme value distribution model during the evaluation reference period is predicted.Based on the measured structural data and normative statistics,a dead load effect distribution model is established.Based on the limit state of the flexural bearing capacity,the structural reliability calculation model of the reinforced concrete simply supported girder bridge is established.Considering the structural resistance time-varying model and the load effect time-varying model,the Monte Carlo sampling method is used to calculate the structure using the MATLAB program.Time-varying failure probability and time-varying reliability index,the reliability attenuation characteristics of the structural bending capacity are obtained,and the remaining service life of the bridge structure is estimated.