Heavy Traffic Detection Using Accelerometric and Displacement Sensors

This paper deals with the preliminary results of a dynamic monitoring system installed on a three span bridge of the Italian road network. The setup includes accelerometers, inertial dis-placement sensors, and displacement transducers. The main objective is to evaluate the dynam-ic response of the deck under normal traffic conditions, with particular attention to the identifi-cation of heavy vehicle transits. The proposed methodology combines the joint analysis of acceleration and displacement meas-urements recorded during traffic induced events. In addition, relative movements at the expan-sion joints are investigated to assess the consistency of the overall structural behaviour under service conditions. The study also aims to assess the possibility of detecting heavy traffic events by means of threshold values applied to the measured dynamic quantities. The identification of vehicle trans-its is particularly relevant for bridges located in remote areas, where simple and low power monitoring systems may provide useful information on the operational conditions of the infra-structure without requiring continuous video based traffic surveillance. The proposed approach is intended to provide useful indicators for the identification of traffic induced loading condi-tions and for the assessment of the operational behaviour of the bridge under service conditions.