Traffic and wind simulation for extreme loads on long-span bridges

Long span bridges are repeatedly subjected to the simultaneous presence of multiple vehicles and predominantly vulnerable to wind induced effects. This paper presents an advanced traffic-wind modelling approach that extends and improves the load prediction capabilities within both the above mentioned load categories dependent on the given site-specific traffic and wind conditions. The traffic load on a bridge is modelled using a random mixing process for trucks and cars in each lane, where each vehicle is modelled individually with driver behavior parameters assigned randomly. The wind load on a bridge is divided into erratic components the modelling of which is based on the spectral tensor method. A general framework for analyzing for the combined effect of extreme traffic and associated wind loading in ultimate limit state analysis is developed and studied for a cable-stayed bridge.