State-of-the-Art Sensing Technologies for Transportation Infrastructure Condition Assessment

Over the last two decades, awareness of the importance of maintaining the nation's investments in transportation infrastructure has increased. One manifestation of this concern was the management systems requirements in the Intermodal Surface Transportation Efficiency Act of 1991. While many of the decision-making and modeling techniques developed for these systems are reasonably mature, the extent to which the systems are actually integrated into the policy process is less than might be expected. A number of institutional barriers exist, but the reliance of existing systems on visual condition assessment data may also contribute. The last decade has also witnessed revolutionary developments in structural sensing and non-destructive evaluation technologies. In particular, the emergence of fiber optic technology and micro electromechanical systems (MEMS) has allowed high-performance interrogation of infrastructure components at data rates, channel counts, and resolution levels never before achievable. These sensing systems, when used in conjunction with specialized data mining and analysis algorithms, provide an integrated approach to in-situ infrastructure condition assessment. This is particularly important as owners seek to reduce costs associated with condition assessment, corrective action, and prolonging service life. However, with the exception of isolated demonstration projects, these state-of-the-art technologies have not been applied widely to condition assessment of transportation infrastructure. Although the techniques described can apply to pavements, geotechnical features, and other components of transportation infrastructure, this paper focuses on bridges. The paper briefly describes the state of the practice for bridge condition assessment. Next, the paper reviews fiber optics, as one of the promising state-of-the-art sensing technologies, and some key analysis approaches taken in analyzing data with the goal of condition assessment (at a point in time) and health monitoring (changes over time). We then discuss two applications of the sensing and analysis methodologies. The paper concludes with an appraisal of the future of these techniques in transportation infrastructure condition assessment.