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.