Evaluating the Feasibility of Robotic Crawler Deployed Ground Penetrating Radar to Assess Repairs of a Concrete Hydroelectric Dam Spillway in Alabama, USA

Abstract

Dams and the water systems they support must be monitored, maintained, and repaired when necessary so they can continue to provide benefits to the communities they serve. This study presents the methods and results from a robotic crawler-based ground penetrating radar (GPR) inspection of rehabilitated concrete from a hydroelectric dam spillway located in Alabama, USA. This spillway, which was recently inspected and repaired, showed evidence of spalling which indicated internal structural deterioration. Standard practice would leave these repairs uninspected or put the wellbeing of people at risk when deploying them on the spillway for manual inspections. GPR data were recorded from recently rehabilitated and resurfaced areas of the site to evaluate the capability of a remotely controlled robotic crawler system to assure repair quality efficiently and effectively. The results indicate that high quality data can be recorded from repairs without the need for manual inspection. The GPR was able to resolve repair length, thickness, number of reinforcements, reinforcement spacing, and cover depth. The study encountered several difficulties, and the author proposes future pathways of development for safely inspecting critical dam infrastructure with steep slopes and slippery, rough surfaces.