Steel bridges are susceptible to fatigue damage under traffic loading, and many bridges operate with existing cracks. The discovery and long-term monitoring of those fatigue cracks are critical for safety evaluations. In previous studies, the ability of the soft elastomeric capacitor (SEC) sensor that measures large-area strain was validated for detecting and monitoring fatigue crack growth in a laboratory environment. In this study, the performance of the technology is evaluated for field applications, for which an approach for long-term monitoring of fatigue cracks is developed. The approach consists of an integrated system, termed the wireless large-area strain sensors (WLASS), for wireless data collection and storage and a signal processing algorithm for monitoring fatigue cracks with bridge response induced by traffic loading. In particular, the WLASS consists of soft elastomeric capacitors (SECs) combined with sensor boards to convert capacitance to a measurable change in voltage and a wireless sensing platform equipped with event-triggered sensing, wireless data collection, cloud storage, and remote data retrieval. A modified crack growth index (CGI) is developed through detection of peak-to-peak amplitudes of the wavelet transform. Using the measurements from the WLASS, the modified CGI is able to obtain the crack status under various loading events due to random traffic loads. The performance of the developed approach is validated using a steel highway bridge.
This paper investigates the mechanism behind the wind-induced vibration of high mast illumination pole (HMIP) structures using wireless smart sensors. Several video recordings revealed significant vibrations of an HMIP under wind loading in Kansas, resulting in large cyclic displacements. In this study, to facilitate the estimate for the main cause of the HMIP’s vibration, finite element modeling and video analysis are employed to evaluate the fundamental natural frequencies and the recorded vibration frequencies of the HMIP of interest. Meanwhile, a 100-foot-tall, galvanized steel HMIP with three LED luminaires is selected for long-term vibration monitoring. A wireless smart sensor network is designed to monitor the structure's acceleration response, wind speed, and wind direction to further investigate the primary cause of the excessive wind-induced vibrations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.