Study On Structural State Identification And Long Term Reliability Of Reinforced Concrete Arch Bridge

Reinforced concrete arch bridge of light weight,large capacity across the structure,lightweight,clear force,therefore,it has been built in large quantities in the 20 th century.However,due to the low load level of design,with the development of China’s economy,the increase of traffic flow makes this type of bridge in the state of overload service during a long time,showing different degrees of disease.The bearing capacity of bridge will reduce sharply.The design is expected,the bearing capacity of many bridges have not met the given requirements,and it must be maintenance and reinforcement.This article relies on the engineering background of the treatment of Fujiang second bridge disease,the type and reason of disease and reinforcing method for reinforced concrete arch bridge,finite element model updating of reliability evaluation and forecast research are carried out,the main works are as follows:(1)Response surface method in the model and its application of reliability evaluation were introduced.In view of the shortcoming that Monte Carlo method can not adopt the iterative computation to fit the response surface model of the nearest failure surface,the explicit expression of the load effect is fitted by the response method,combined with the Member section bearing capacity formula,the explicit expression of structural performance function was put out.(2)Based on measured deflection data of static loading test of after-reinforced bridge,the finite element model of the Fujiang second bridge was modified by using response surface method.By the load test comparison of different operating conditions,the conclusion is drawn that the correction efficiency of the model under different load cases is different.Taking into account that the lacking of data under the single condition,as a result the input data to model is less.In order to ensure the reasonableness and correctness of the model,combined actual deflection under different conditions were to amend it.And given the condition of different weights,finally through the values of weight coefficient and parameter were solved by the MATLAB Optimization Toolbox.(3)The calculation of reliable degrees index on fujiang River second bridge for has been finished by using response surface method combined with Monte Carlo method.The results shows that 120 m main across main arch circle will reached hosted capacity limit State ahead of 60 m.It’s not match the history fujiang River II Bridge reinforcement.After the analysis of the main causing of it,the 2cm arch foot forced displacement is applied to the foot of the two 60 m cross arch foot.Considering the increased traffic,the vehicles load increases 1.1 times times,the reliable degrees index were calculated.The analysis of this paper is verified.Finally,considering the displacement of arch bridge,based on factors such as traffic increases,according to the updated finite element model,the reliability of the reinforced Fujiang second bridge were predicted.