Research On The Performance And Damage Assessment Method Of Concrete Bridge Under Overload

In recent years,due to the increasingly overloading situation,a large number of concrete bridges have been damaged during service period and are in sub-healthy or dangerous state now.Aiming at the structural and functional characteristics of existing concrete bridges,it is of great significance to study the impact of the damages in different structural components caused by overloading on the safety of bridge operation.Then by using scientific means to conduct comprehensive and credible damage assessment,the safety of transportation has been ensured.Taking Dongpu Bridge in Guangzhou as the research background,this paper studies the stress performance of the bridge under overloading and the safety margin according to domestie and foreign eodes through finite element analysis.Also,a damage assessment of the bridge under overloading has been proposed.The main contents of this paper are:(1)Based on the existing achievements and data,the impact of overloading on bridges and the research status of bridge evaluation methods has been summarized.(2)According to the load investigation of Dongpu Bridge,a suitable overloading vehicle model is proposed and the performance analysis of the bridge is carried out.The result shows that overloading has the biggest impact at the end of side span and middle span,where stress is larger and cracks appear.Comparing to gross vehicle weight,axle-weight has closer relationship with the maximum principal tensile stress.Overloading makes the deflection of the bridge much larger and cracks generate easily.(3)Combining Chinese old and new codes with major developed countries’,the safety margin of bridges under overloading is discussed.The outcome shows that compared to 85 Codes,the standard resistance to overloading of bridges has not much improved in Chinese 15 Codes.Bridges designed in accordance with the British Code have higher flexural and shear capacity.(4)By both analytic hierarchy process(AHP)and fuzzy comprehensive evaluation method,the assessment model and method for bridge damage under overloading are proposed,which is used in the damage assessment of the Dongpu Bridge.