Site-Specific Extreme Load Estimation of a Long-Span Cable-Stayed Bridge

To provide benefit for design, rating, evaluation and management of signature bridges, site-specific extreme wind speeds, structural temperatures, and traffic load effects of a long-span cable-stayed bridge were estimated using relatively long-term structural health monitoring (SHM) data and compared with respective design values in this paper. The generalized Pareto distribution was adopted and briefly introduced to predict the extreme values in consideration of its advantage in making full use of limited measurement data available. The configuration and characteristics of the 3rd Nanjing Yangtze River Bridge and its SHM system were then presented. The extreme wind speed at the deck level and the four extreme temperatures of the bridge were estimated and compared with the corresponding design values. After a brief introduction to the simulation of traffic load effects, five extreme traffic load effects were finally estimated and compared with the design ones. The comparative results showed that the site-specific extreme wind speed, uniform girder temperature change, and five traffic load effects are all lower than the respective design values. The site-specific extreme vertical and transverse girder temperature differences and the site-specific extreme tower temperature difference were, however, larger than the respective design values.