Structures Congress 2020 239 © ASCE Infrastructure Structural Health Monitoring via Infrasound R. Danielle Whitlow, Ph.D., P.E. 1 ; Isaac L. Howard, Ph.D., P.E., F.ASCE 2 ; Anna M. Jordan 3 ; Sarah L. McComas 4 ; and Mihan H. McKenna, Ph.D. 5 1 U.S. Army Engineer Research and Development Center, Vicksburg, MS. E-mail: danielle.whitlow@usace.army.mil 2 Dept. of Civil and Environmental Engineering, Mississippi State Univ., Mississippi State, MS. E-mail: ilhoward@cee.msstate.edu 3 U.S. Army Engineer Research and Development Center, Vicksburg, MS. E-mail: anna.m.jordan@usace.army.mil 4 U.S. Army Engineer Research and Development Center, Vicksburg, MS. E-mail: sarah.mccomas@usace.army.mil 5 U.S. Army Engineer Research and Development Center, Vicksburg, MS. E-mail: mihan.h.mckenna@usace.army.mil ABSTRACT Infrasound is an emerging remote sensing technology related to low-frequency acoustics. This paper provides a state-of-the-art assessment of infrasound’s ability to detect and monitor a diverse array of infrastructure, including a discussion of best practices for use and potential limitations. This paper follows field experiments where researchers were focused on a single bridge source with infrasound (remote monitoring) and on-structure instrumentation, in which the on-structure data validated infrasound data. After completing the assessment of the bridge of primary interest, the question of wide-area infrasound monitoring was raised. While the original experiment series focused on a single bridge source, further evaluation of the data set identified multiple sources within the area of study via infrasound, allowing investigation of the feasibility of multiple-source monitoring. These additional sources included hydraulic features, bridges, industrial activity, and a dam. Some of these features were detected via infrasound while others were not. INTRODUCTION AND BACKGROUND In 2017, the American Society of Civil Engineers (ASCE) rated the nation’s infrastructure at a D+ for the second time in four years (ASCE 2017). As the amount of infrastructure in need of persistent monitoring increases and the resource pool remains limited, the need for cost effective monitoring solutions, e.g., sensing, is essential. This paper focuses on the use of infrasound for remote infrastructure structural health monitoring as it relates to transportation infrastructure and the assessment of transportation networks. In the last decade, the field of remote sensing has undergone rapid development as it offers several advantages over traditional methods of inspection and infrastructure monitoring including no need for direct access to the structure, no function (e.g. traffic) stoppage, and the ability to monitor persistently. This manuscript focuses on the use of infrasound for remote, non- line-of -sight, persistent monitoring as a supplementary tool to traditional methods of inspection and monitoring. Infrasound is traditionally defined as acoustics below the range of 20 Hz (Bedard and Georges 2000; Evers 2005; Christie and Campus 2010). Research efforts by the U.S. Army Engineer Research and Development Center (ERDC) utilize arrays of infrasound sensors deployed surrounding the structure of interest (Simpson et al. 2019 provides detailed Structures Congress 2020 Downloaded from ascelibrary.org by 18.206.13.133 on 07/22/20. Copyright ASCE. For personal use only; all rights reserved.