Investigation of the Stiffness of a Specially Strengthened Bridge When Crossed by Very Heavy Vehicles – A Case Study

The measurement of bridge deflection induced by a motor vehicle is an effective way of verifying the weight of the vehicle, and even of determining the layout of its axles. If the vehicle’s weight and the impacts of its individual axles are known, deflection measurements can be used to verify the stiffness of the bridge structure and to evaluate the effectiveness of steel-concrete composite span integration. The bridge in this case study had been specially permanently adapted to carrying very heavy loads, generated by overweight transports reaching the total weight of a few to over 10 MN. The results of measurements of span deflections induced by a heavy vehicle and the way they were used to assess the weight of another overweight transport unit crossing the bridge are presented in the paper. The existing strengthening of the bridge has been found to be universal and effective for various overweight transports.