On the effectiveness of vibration-based monitoring for integrity management of prestressed structures

In this paper, the effectiveness of vibration-based tests for the detection of damages for prestressed concrete beams is investigated. Despite large research efforts, discrepant and sometimes contradicting conclusions have been drawn regarding the efficacy and reliability of vibration-based monitoring for prestressed structures. Herein, a contribution to this discussion is provided by tackling the problem from a different perspective. Specifically, the question that this paper intends to answer is: “Do vibration-based tests support decision-makers in integrity management operations for prestressed elements?” The discussion is carried out by comparing the performance of prestressed and ordinary reinforced concrete beams with similar capacities. Both analytical and numerical case studies are considered. Results show that, for prestressed beams, in contrast to reinforced concrete beams, modal parameters can provide information regarding damage only when the structure is close to its ultimate conditions. This makes this information hardly useful for integrity management purposes and the effectiveness of vibration-based tests questionable for this type of structural element.