The safety assessment of existing bridges is a relevant topic for the management of the transport infrastructure system of the EU countries due to the increase of traffic loads and aging of the structures. Among the actions applied to bridges, traffic loads are in general the most significant variable action to be considered when the assessing existing structures.

Usually, engineers perform the safety assessment by using the traffic load models given in the design codes for new structures. This approach might lead to unnecessary conservativism in the assessment because the design load models do not represent the specific loading conditions of the bridge under investigation. In addition, the residual service life of existing structures is generally shorter than the 50 or 100 years period assumed in the design standards for new structures.

This paper presents the vision and preliminary results of the Horizon CSA IM-SAFE project about the use of monitoring of traffic loads and conditions for assessing the structural safety of existing bridges. Current monitoring technologies, methods for assessing traffic loads models and approaches to the safety assessment supported by traffic load data are presented. Furthermore, the needs for standardisation to enable the safety assessment based on the actual traffic loads at the probabilistic and semi-probabilistic levels are discussed.