Loads Of U Type Aqueduct Over Time Based On The Reliability Of The Safety Factor Method

Under the impact of the surrounding environment,the U type aqueduct in service will gradually age.This is an irreversible process that will inevitably affect the performance of the structure in service,even its safety.In this paper,by using the method of connecting theoretical analysis,field measurement,finite element simulation,the idea that the carrying capacity of the cross double cantilever U type aqueduct decreased over time has been analysed and estimated,and the multiple factors like the degradation of concrete strength,the corrosion of steel,were considered on account of the reliable coefficient of safety.The main research work and results are as follows:1.The various factors leading to the resistance's decreasing of structures in service,and various resistance parameters were taken into consideration.And the steel and concrete's performance degradation model with a time-dependent variable was made.Therefore,the foundation to assess the degradation of the aqueduct's carrying capacity was laid.2.The analysis method connecting the reliability theory and the coefficient of safety,was advanced in this paper when the U type aqueduct in Shi Dongjiang was the research object.Moreover,the four failure criterions,including the cracking,antipressureof concrete,ecessive tension and deflection of steel,are defined.And the failure criterions and the evaluation criterion of the aqueduct's residual life formed an organic unity.Furthermore,the minimum material strength requirements were determined and the method to deduced residual life of the aqueduct from the material degradation principle,was studied.3.The site materials testing and filling water load test to U type aqueduct in Shi Dongjiang were completed.The steel and concrete's performance degradation model was proved correct in site materials testing.Under the condition that the strength of the aqueduct was above the minimum requirements,it revealed that U type aqueduct in Shi Dongjiang was still elastic in the load test.And the test section of the aqueduct had enough carrying capacity,which demonstrated that the aqueduct was safe for using.4.The mechanical properties of the U type aqueduct's different stages were analyzed: the numerical simulation results in the initial stages,illustrated that it's feasible to analyse this aqueduct with the simplified Structural mechanics method counting by beams;by comparing the simulation results in current stage with that of the site load trials,the Three dimensional finite element analysis was proved reliable;the life of the aqueduct was predicated according to the theory while the simulation results showed the correctness of the prediction method.