Comparative Sensitivity Analysis of Virtual Axle Approaches in Bridge Weigh-in-Motion Systems

Abstract

<p>Bridge Weigh-in-Motion (BWIM) has been widely used for axle load estimation and bridge health monitoring (BHM). However, traditional approaches to using BWIM for BHM require knowledge of gross vehicle weight (GVW), limiting its BHM capabilities. The virtual axle concept, which involves adding a weightless axle to detect structural changes, overcomes this limitation. This study compares strain-based, displacement-based, and rotation-based virtual axle approaches to determine their effectiveness for BHM. A vehicle-bridge interaction model is used to simulate BWIM under various damage conditions with different sensor placements. The Virtual Axle Indicator (VAI) is calculated to summarize virtual axle measurements, and sensitivity analysis is performed to evaluate each approach’s ability to detect bridge damage and changes in structural conditions.</p>