Detection And Damage Identification Methods For A Bridge With Four-span Continuous Steel Box Girder In Second Ring Road Of Changchun City

Compared with concrete bridge, steel bridge has some main features:(1)It has a strongseismic capacity, and can recovery easily by repair after earthquake;(2)The capacity ofresistance to various stress are close,that means the capacity of resistance to pull, pressure,bent, twist and cut are close.Up to this point the steel bridge can better adapt to the complexstress state;(3)Using staged installation during the construction. Using welding, boltingand rivet connection in assembling. The construction speed is quick;(4)It has light weightand strong across capacity.It can reduced bearing of lower structure.Because steel bridgewith these characteristics, it has been widely used. Steel bridge belongs to a steel bridge,which has a larger bending and torsional capability, so steel bridge has been widely used inhighway and city bridges.With the emergence of steel bridge problem in application and production practices.Researchers have conducted on a series of steel bridge research.Research focused on theform of steel bridge construction, the construction methods of steel bridge, steel bridge ofstress analysis methods, design methods, and the steel bridge steel bridge deck pavement andso on.While the research for detection and damage recognition of steel bridge is still in itsinfancy.Then accurate theoretical analysis can not replace experimental study, and thereforecarry out this kind of bridge load test, test various load conditions of static response anddynamic response, provide the basic data for the improvement of the theoretical analysis anddesign method is necessary.Furthermore,through bridge inspection can clear the using stateof the bridge,then we can avoid major accidents in the service period of the bridge.Damageidentification of bridge structure is the supplement of bridge inspection work, which canfound the local damage of bridge structures. Proven local damage of steel bridge has greatsignificance.In summary,research testing and damage detection method for steel bridge is verymeaningful. This paper is based on the project of bridge with four-span continuous steel box girderin second ring road of Changchun city,to research the detection and damage identificationmethod for steel box girder bridge.The specific work is as follows:1.We analyze the characteristics of steel box girder bridge from four aspects:thestructure of the steel box girder bridge, the construction method, theoretical analysis methodand the bridge deck pavement mechanical characteristics.2.The static load test of steel box girder bridge, and the key technology of dynamicloading test are discussed in this paper. Relying on engineering theory analysis model isestablished, and formulated the load test plan. We make the static load test and dynamic loadtest to the bridge working conditions that we relied on,and measure the static characteristicsand dynamic characteristics of the bridge.Based on the static characteristics and dynamiccharacteristics,we analysis and evaluate the use of engineering condition we relied on.3.Formed the method of two steps for steel box girder bridge damage identification,andconstructed damage index,which is Suitable for steel box girder bridge.First,use the modalcurvature difference to damage location.Second,use BF neural network to identify thedamage degree based on the structural damage index. Verify this damage identificationmethod by combining the method of numerical simulation calculation and engineeringapplication.