Analysis Method And Experimental Research On Load Limitation Of Reinforced Concrete T-Beam Bridge

With the vigorous development of social economy in our country,heavy trucks have become the main carrier of highway transportation,which not only seriously threatens the structural safety of highway bridges,but also brings great pressure to bridge operation and management.In the past ten years,bridge collapses caused by overweight vehicles often occur,which cause great damage to the life and property safety of the country and the people.Therefore,it is very necessary to carry out scientific and reasonable operation evaluation and load limit management of the bridge.This paper takes the bridge load limit analysis model as the theoretical basis,takes an in-service reinforced concrete T-beam bridge in Liaoning Province as the research object,systematically analyzes its load limit value,and verifies the rationality of the proposed load limit value through static load test and numerical simulation.The main research work includes:(1)Based on the analysis of the current situation of overload operation of highway bridges in China,this paper points out the academic significance and engineering value of load limit research,and studies the highway bridge load limit analysis model and related programs proposed by the research group on the basis of structural reliability theory,to provide a theoretical basis for the load limit analysis of this paper.(2)Taking a reinforced concrete T-beam bridge in Liaoning Province as the research object,according to the General Code for Design of Highway Bridges and culverts(JTG D60-2015),the resistance standard value,dead load standard value effect,vehicle load standard value effect and resistance correction coefficient of reinforced concrete T-beam bridge are calculated.According to the resistance correction coefficient and the live dead load ratio,the limit load coefficient and the limit load value under the corresponding limit load safety grade are calculated,and the adaptability of the limit load value is verified by the limit value of deflection and crack width.(3)The structural model of the beam bridge is established by using the finite element software MIDAS/Civil,and the initial model is modified according to the field test data,and the numerical simulation is carried out on the basis of the modified model,combined with the static load test efficiency and the code limit value to verify the safety and rationality of the bridge load limit value obtained by the proposed highway bridge load limit analysis theory.The study shows that,for the existing reinforced concrete simply supported beam bridge,under the premise of considering the resistance correction coefficient,the bridge load limit value with the live and dead load ratio as the basic parameter can ensure the safe operation of the bridge.The purpose of this paper is to provide guidance and reference for the formulation of bridge load limit standards and the safe operation and management of bridges.