Bridge health monitoring in the United States: A review

Abstract

The assessment of bridges' health has become a relevant component of the maintenance especially in those countries in which many structures are rated in poor condition and/or are over 50 years old. Additionally, the permanent monitoring of bridges helps engineers in validating the design prediction of bridge structural response to external loads. With more than 600,000 highway bridges, 46.4% of which rated as fair and 7.6% rated in poor condition, United States is one of those countries in which the installation of reliable bridge health monitoring systems is strategically necessary to minimize and optimize repair and rehabilitation costs and to minimize the risk of failures. In this paper, a thorough review of the scientific literature on structural health monitoring systems installed in U.S. bridges over the last 20 years is presented. This review aims to offer interested readers a holistic perspective of recent and current state-of-the-art bridge health monitoring systems and to extract a general paradigm that is common to many real structures. The review, conducted through a comprehensive search of peer-reviewed documents available in the scientific literature, discusses more than sixty bridges in terms of the instrumentation used, scope of the monitoring, and main outcomes. Overall, it was found that the monitoring systems provide a valuable tool to compare the structural responses predicted using analytical or numerical tools with the real response of the given structures. Owing to the relative short time span of the monitoring period, most of the monitoring systems did not flag any serious structural flaws that required the closure of the bridge monitored.