Studies of Overload Effect on Fatigue Damage of Steel Bridges

Possible accidental overloading on a bridge occurs when an unexpected disaster happens. This paper studies the overloading effect on the fatigue damage of bridges on the basis of a nonlinear fatigue damage model. The model is applied to evaluate the fatigue damage and service life of the Tsing Ma Bridge (TMB), under normal traffic loading and possible accidental overloading. The calculated results under simulated con¬ditions for TMB showed the significant effect of overloading on the fatigue accumulation and residual life of the bridge. Typhoons are a significant factor in the design of bridges in Hong Kong. With the help of the data acquired by the Wind and Structural Health Monitoring System (WASHMS) installed in TMB, it is possible to investigate whether a typhoon will generate an overstress range in the local members ofTMB. It is concluded that typhoons do not usually generate local overstress inside bridges like TMB