Fatigue Stress Analysis Of Orthotropic Steel Bridge Decks In Marine Environment

Orthotropic steel bridge deck was first invented by German engineers.It has been widelyused in the world because of its advantages such as light weight and high strength.However,with the increase of bridge service period and the repeated effect of vehicles,many countries have found different degrees of fatigue cracking on the steel bridge deck.On the other hand,most of the long-span highway bridges that have been built and constructed in our country are located in the sea,which is vulnerable to environmental corrosion.For the corrosion of the bridge deck,cyclic stress of the vehicle load will increase the fatigue crack growth,shorten the service life of the component,and even cause catastrophic accidents.This paper takes Xinghai Bay sea-crossing bridge as the engineering example,using finite element software ABAQUS to establish section model of steel bridge deck,the stress characteristics of typical fatigue structures under different degrees of marine corrosion are analyzed,and fatigue checking is carried out with the existing fatigue design codes.The main research contents include the following aspects:(1)Review the development history of orthotropic steel bridge deck,elaborate the research status of the fatigue performance of orthotropic steel bridge deck.Based on the application of steel deck in sea-crossing bridge,summarizing the corrosion types of steel bridge in marine environment,and giving the uniform corrosion model under the real environment.(2)Using ABAUQS to establish section model of steel bridge deck.Firstly,stress characteristics of the typical structural details of bridge deck under moving loads are analyzed,and the structural details are checked with the existing fatigue resistant design specifications.Secondly,the fatigue life of structural details is estimated based on the fracture mechanics method.Finally,on the basis of considering different corrosion years,stress of structure details are analyzed and made comparison.(3)Based on the investigation of the existing orthotropic steel bridge deck design data,selecting appropriate parameters modeling,comparing the influence for structure detail stress caused by different parameters such as beam spacing,the setting of longitudinal partition and diaphragm plate welding hole.