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Scour, or the erosion of soil and sediments near bridge piers and abutments, accounts for the majority of overwater bridge failures. This study focuses on evaluating the use of a driven piezoelectric scour sensing rod, where the real-time dynamics of the voltage response of the sensing rod is used to determine scour depths using the inverse relation between natural frequency and the rod's exposed length. A poly (vinylidene fluoride) polymer strip forms the main sensing component of this prototype sensor. After confirming the viability of the sensing concept through various idealized tests, the response of the sensors was studied in scour conditions simulated in a laboratory flume. The sensors were driven into the soil surrounding a cylindrical pier. As the scour hole evolved, the exposed length of the sensors changed, causing the measured natural frequencies to also vary. Scour depth at each sensor location was determined using a simple cantilever beam eigenfrequency analysis where the soil support fixity was modeled with a rotational spring. The results were promising in that the sensors were capable of detecting scour depths and the scour hole topography with reasonable accuracy. As is the case with other rod-like scour sensors, vulnerability to debris and installation difficulties are some of the limitations that need to be addressed in future real-world implementations.

The highly optimized performance of nature's creations and biological assemblies has inspired the development of their bio-inspired artificial counterparts that can potentially outperform conventional systems. In particular, the skin of humans, animals, and insects exhibit unique functionalities and properties and has subsequently led to active research in developing skin-inspired sensors. This paper presents a summary of selected work related to skin-inspired tactile, distributed strain, and artificial hair cell flow sensors, with a particular focus on technologies enabled by recent advancements in the nanotechnology domain. The purpose is not to present a comprehensive review on this broad subject matter but rather to use selected work for outlining the diversity of current research activities.

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