Moving point load approximation from bridge response signals and its application to bridge Weigh-in-Motion

This paper presents a revised theoretical interpretation for the analysis of bridge response signals arising during a vehicle passage. The derivation shows that it is possible to approximate the forcing function from bridge re-sponses, by means of a finite difference scheme. This Point Load Approximation (PLA) is also formulated into explicit expressions following classic beam theory. This idea is then generalized to include other load effects and their corresponding time derivatives. These findings are particularly relevant for Bridge Weigh-in-Motion (BWIM) applications. The influence line for a BWIM system with multiple sensors can be explicitly defined using the presented formulation. The theory and applications are validated numerically by means of examples and case studies. These studies include the performance evaluation of a multiple strain sensor BWIM system, as well as, a novel approach to acceleration-based BWIM.