Wind-induced fatigue life prediction of bridge hangers considering the effect of wind direction

The safety and reliability of a bridge structure are directly influenced by the service status of its hangers. This study takes into account the impact of wind direction and develops a wind-induced fatigue damage and life assessment model for the hangers of the Jiubao Bridge. Specifically, wind field data from the bridge site in 2015 year was collected via a structural health monitoring (SHM) system. From this, the longitudinal and transverse fluctuating wind speeds were generated based on the mean wind speed and wind power spectrum, and then a wind load spectrum was constructed with the influence of wind direction. The stress time history curves of the hanger under varying wind speeds and directions were then obtained using a finite element model of the bridge hanger. This study also integrates the Palmgren-Miner criterion, rainflow counting method, S-N curve, and master S-N curve to calculate the fatigue damage of bridge hangers. Additionally, a fatigue damage model considering the combined effect of wind speed and direction was derived, and this paper provide an assessment of the fatigue life of bridge hangers under the influence of wind direction. The result show that the fatigue life of the middle long bridge hanger is 366.32 years based on the master S-N curve and 179.46 years based on the S-N curve; The fatigue life of the edge short bridge hanger is 821.94 years based on the master S-N curve and 534.70 years based on the S-N curve.