Bridge weigh-in-motion using a moving force identification algorithm

Abstract

Bridge weigh-in-motion technology is the process of using measurements from a bridge to calculate the weight of a passing vehicle. This paper investigates the use of a moving force identification (MFI) algorithm to calculate vehicle axle loads. The calculation of forces exerted on a bridge from bridge measurements is an inverse dynamics process. Like many inverse dynamics processes, it is ill-conditioned in nature and a regularisation technique is needed. Tikhonov regularisation is used in the algorithm in this paper. The choice of the Tikhonov regularisation parameter is achieved commonly using the L-curve method. This paper investigates the use of a new, simpler type of curve to choose the regularisation parameter for bridge weigh-in-motion applications. It is based on calculated vehicle axle-weight ratios for a range of regularisation parameters. The method has the advantage of allowing the choice of regularisation parameter to be based on a realistic calculated axle-weight ratio. Calculated vehicle axle loads of quite good accuracy are achieved using this method.