Influences Of Structural Detail And Critical Design Parameter On Fatigue Properties Of Orthotropic Steel Bridge Deck

Orthotropic steel deck has been applied in more and more large span bridges because of its light weight, integration, high bearing capacity and comfortability in operation. For the complex configuration, serious effeets of residual stresses, some details are prone to fatigue, when the fatigue cracks propagate a specific length, the service safety of the whole bridge will be intimidated. Under this background, the fatigue properties of orthotropic steel deck were studied form two aspects of structural details and design parameters. In this thesis, the following aspects are investigated:(1) In order to improve the fatigue orthotropic properties of steel bridge deck, the cutout shape was optimized by numerical simulation. The calculation models of six common cutouts were established, and the finite element model was calibrated by comparing the calculated results with the measured values derived from a full scale orthotropic steel deck test specimen with U shape cutouts. The effects of the cutout shapes and geometry size on the stress distribution at the crossbeam web cutouts were discussed, which give a useful technical reference to the fatigue design of steel bridge deck.(2) Influences of thickness of steel deck, thickness of web of floor beam, thickness of U rib and height of U rib on mechanical behaviors of orthotropic steel deck was studied. Reasonable value ranges of these parameters were given. Concept of reasonable general applicable degree of match of various design parameters of orthotropic steel deck and its formula were proposed. In reasonable value ranges of these parameters, three sets of reference value of design parameters of orthotropic steel deck were given by considering strength and economy(steel) comprehensively and calculating reasonable general applicable degrees.