Research on Fatigue Life Design Optimization of Orthotropic Steel Deck
By using the finite element method,the main joints of the orthotropic steel deck of the steel box girder segment before and after the optimization of the steel UHPC super light composite beam used for the steel deck pavement of a bridge are analyzed.The distribution characteristics of the control stress and the stress influence surface of the main fatigue cracks under the wheel axle load are studied,and a more comprehensive relationship between the load effect and the stress effect is established;the stress history and the corresponding stress spectrum of the real bridge under the design fatigue load are further calculated.According to the structural details of orthotropic steel bridge deck in the design fatigue life cycle,the corresponding fatigue cumulative damage is calculated according to Miner's fatigue damage accumulation theory,and its fatigue life is evaluated.The main conclusions are as follows:when ordinary steel deck pavement is used,the fatigue cumulative damage degrees of the main fatigue cracks near the joints of top plate and U-rib,U-rib and diaphragm are greater than 1 in the design service life cycle,and there is a high risk of fatigue cracking.After the design optimization of steel UHPC ultra lightweight composite deck,the fatigue resistance of the connection between the top plate and the U-rib is significantly improved,which can meet the service requirements of the fatigue resistance design within the design life cycle of the bridge.However,the design optimization has limited impact on the fatigue resistance of the diaphragm-U rib-top plate connection.During the design service life cycle,there is still a high risk of fatigue cracks in C.5,C.6,C.6.1 and C.7,which should be paid close attention to.
bridge engineeringorthotropic steel decksteel-UHPC composite deckfinite element numerical simulationfatigue life
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