Identifying Magnitudes and Locations of Loads on Slender Beams with Welded and Bolted Joints Using Strain Gauge–Based Force Transducers with Application to a Portable Army Bridge

Abstract

A strain gauge–based force transducer methodology has been developed to identify magnitudes and locations of loads on noncontinuous, nonhomogeneous, slender beams with welded and bolted joints. Slopes of bending moment curves on two sides of a load are calculated from measured strains on a beam. Four uniaxial strain gauges are mounted to the bottom surface of the beam, with two strain gauges on each side of the load, to form a force transducer. A previously developed calibration method can be used to account for discrepancies between theoretical and actual scaling factors. Four or more force transducers are needed for calibration in this work. The force transducer methodology is experimentally validated on a continuously tapered aluminum beam with a series of welded joints, a half-aluminum and half-steel beam with two different cross sections and a bolted joint, and a full-scale portable Army bridge at the U.S. Army Aberdeen Test Center.