ABSTRACT
ABSTRACT: The prediction of the actual traffic loading response for bridges in service is of great importance. Influence lines of load effects for multi-span large bridges are remarkably different from those of common bridges, and are not specifically considered by current traffic load models. In this paper, typical influence lines for multi-span large bridges are investigated under different traffic states. Full influence lines, and influence lines for minimum and maximum patterned loading effects are considered. Traffic states are detailed as general state, congested state and extreme state. For each state, random traffic flow is simulated using a microsimulation model, and characteristic load effect values are also obtained by extreme value analysis. Finally, the characteristic values of load effect for the different forms of influence line are compared. Results indicate that extreme responses for load effects of multi-span large bridge are sensitive to the traffic loading scenarios, and the allowance for load patterning made. Since current requirements cannot cover these features, a new traffic loading model is recommended for the assessment of such special structures.
