Shear force–based method and application for real-time monitoring of moving vehicle weights on bridges

A new approach for monitoring the weight of trucks in motion using the bridge response is introduced in this article. The proposed technique is based on the use of strain rosettes for acquisition of shear strains near bridge supports. Bridge weigh-in-motion monitoring using shear force is a new approach that differs from the prevailing techniques based on the measurement of flexural strains. Formulations are introduced using the shear force response of the bridge in the computation of gross vehicle weights. The method requires truck speeds, influence lines, and shear force responses for the computation of gross vehicle weight. All these are acquired by two sets of rosette sensors attached in series on the webs of bridge girders. An experimental program was designed to evaluate the response of the proposed approach in real-time monitoring of moving truck weights. This was accomplished by instrumentation and load testing of a two-span prestressed concrete box girder bridge by a calibrated truck. Field test results are presented and compared with the actual weight of the calibrated truck.