Influence of prestressing strand damage on modal parameters of a hybrid composite bridge beam

Abstract

In-service condition assessment of large civil infrastructure systems has remained a particularly challenging area of research in the fields of nondestructive evaluation and structural health monitoring (SHM). Extensions of theoretically-based and laboratory verified vibration-based methods for assessing damage have been investigated experimentally on full-scale structures within several studies offering mixed conclusions. This paper introduces a recent experimental test program conducted on a full-scale bridge beam subjected to prescribed damage to the tension reinforcement. Details of the experimental testing program and vibration testing of the full-scale bridge beam both prior to and after damage to tension reinforcement are presented. System identification is applied to compare estimates of the natural frequencies, relative damping factors, and mode shapes obtained in the as-built state against those obtained after cutting over half of the tension reinforcement strands in the beam. A data-driven damage detection algorithm previously applied to detect damage in a full-scale bridge is also explored for application to the current dataset.