Traffic Action Effect Reduction Factors

This paper describes research carried out to develop methods for considering site specific traffic actions during bridge evaluation. A new site specific probabilistic model of the static effect of traffic actions has been derived by applying extreme value theory to the results of traffic simulations. A simplified method has been developed which is based on the use of traffic action effect reduction factors which have been calibrated using probabilistic analyses of bridge loads and resistance. Introduction Road traffic load models which are used for design are inherently conservative because of the high uncertainty about traffic actions at the design stage and because the models must be valid for structures of all types and sizes. The increased cost of construction due to the use of a conservative design load model is small and necessary to allow for uncertainty and to simplify the design process. However, once a structure is in service, the cost of an over-conservative evaluation could..