Road bridges are facing the effects of both their ageing and the increase of the traffic loads, which justifies the necessity of combining Weigh-In- Motion (WIM) with Structural Health Monitoring (SHM) solutions for real-time and continuous assessment of the bridge for safety and preventive maintenance purposes.

On December 22, 2021, OSMOS Group SA completed the official assessment of its WiM+D® on a viaduct located in southern Italy, on which a single integrated monitoring system achieved both results: to perform Bridge WiM by using the bridge deck as a scale for the detection and qualification of the traffic loads, and to assess the structural health of the asset through combined strain and vibration analysis. The system implies a low number of sensors and is not intrusive for the pavement, making it an efficient, cost-effective, and comprehensive solution for the structural asset manager (operator and/or owner of the asset).

Pâris Mouratoglou, CEO of OSMOS Group SA, stated that “This achievement by OSMOS constitutes a world premiere for the qualification of its Bridge WiM+D® solution. OSMOS innovative solution for bridges combining Structural Health Monitoring and Weigh-in-Motion integrated system, was officially assessed in terms of its performance by TÜV Rheinland Italia”.

The project, in collaboration with the Province of Matera (Italy), has been carried out on the Salso viaduct, a concrete structure with nine isostatic 32m long spans, composed of four main prestressed concrete beam girders and a reinforced concrete slab. The system has been implemented on two spans and uses twelve sensors, among them eight OSMOS Optical Strands (fibre optic-based strain sensors), and four OSMOS AAA accelerometers. The system includes OSMOS Safe Traffic that uses two ANPR cameras and specialized software to enhance the traffic control. In essence, each one of the trucks driving on the bridge triggers the recording of strain and vibration data that is further analysed for the SHM of the concrete structure, combined with vehicle plate recognition.

The performance of the Bridge WiM system was tested according to the COST 323 methodology and reached the accuracy class A(5) for the vehicle gross weight, which means that weights are assessed within 5% accuracy, in addition to providing strain information, and plate identification for each truck passage .