CableScan: Rapid cable force assessment for cable-supported bridges using mobile microwave radar sensing

Accurate and efficient measurement of cable forces is critical for the structural health monitoring and maintenance of cable-supported bridges. This study presents CableScan, a novel mobile sensing method that employs microwave radar mounted on a vehicle to rapidly acquire dynamic displacements of bridge cables. The mobile system moves along the bridge deck, for example on the emergency lane, stopping at specified positions to measure the displacement responses of cables within a cable plane before proceeding to the next station, thereby covering all cables of the bridge. A corresponding data processing procedure is provided to extract cable displacements, modal frequencies, and cable forces. In particular, the locally weighted scatterplot smoothing method is applied to remove displacement components resulting from bridge deck and vehicle motion. To demonstrate the effectiveness of the proposed system, a detailed case study was conducted on an operational cable-stayed bridge. The results confirm the accuracy, efficiency, and practicality of the CableScan system for in-situ cable force assessment, with an average measurement time of less than one minute per cable. Moreover, the measurement data reveal the vibration modes of the entire bridge, highlighting the broad potential of the proposed system for comprehensive bridge inspection. • Mobile microwave sensing proposed for rapid measurement of all bridge cable forces. • LOWESS smoothing applied to remove effects of bridge deck and vehicle motion. • Demonstrated on a 200-cable bridge, with a mean measurement time of less than 1 min per cable. • Bridge vibration frequencies also identified from the measured displacement responses.