Traffic Load Models and Weigh-In-Motion Data

During the evaluation of an existing bridge, measurements at the site can be used to update the traffic load model. Measurements can be made with either temporary Weigh-In-Motion (WIM) sensors installed on the road surface or with strain gauges installed on the structure. The aim of updating a traffic load model is to avoid costly interventions on an existing bridge that are often proposed as a result of an assessment using a design traffic load model. This paper presents the measurement of traffic loads and effects at a bridge site in Switzerland. Simultaneous measurements with temporary WIM sensors placed adjacent to a bridge and strain gauges on bridge elements were used to study vehicle characteristics and traffic load effects. The results of this study provide valuable Information about the effects of actual traffic on bridges and the use of WIM data for bridge evaluation.