Fatigue reliability analysis on cable of cable-stayed bridge under random vehicle load and wind load

Taking a long span cable-stayed bridge as a project background, the fatigue reliability of cable stay in combination as random vehicle load and wind load was analyzed. The authors firstly, setup traffic and wind load probability models for the bridge based on the traffic survey data and long-term wind velocity data from bridge site; then calculated the stress spectrum of the cable stays under combining loads by running self-compiled wind-vehicle-bridge interaction dynamic response analysis program; finally, evaluated the fatigue reliability and fatigue life with help of cumulative damage theory and Monte-Carlo method. The result shows that the effect of wind load on the fatigue reliability of cable stay is significant, and the influence degree increases in accordance with the order from short cable to long cable. Compared with only vehicle load, the fatigue life of the cable under both vehicle and wind load decreases by the range from 2% to 63%, with an average ratio of 50%.