to redo the work suggests that inspector would spend less time expose to traffic and other dangers. 2.2.3.4 Remote-Controlled Inspection of Conduits Conventional inspection of highway conduits requires an inspector to enter the conduit in order to evaluate the drainage conditions. This can be dangerous due to uncertainties regarding the conduit structural condition, water and sediments in different levels, and the possible presence of contaminants. In addition, a good portion of conduits are inaccessible due to their small diameter or obstructions (water, sediment, and others). This means that a great number of conduits are left uninspected losing appropriate drainage functions. In the past 15 years, the paving industry has used remote-controlled technologies to evaluate small diameter conduits. Since then, new and emerging technologies have been developed to inspect all types of conduits. Recently, the Ohio Department of Transportation (OHDOT) sponsored a tech scan research project to evaluate remote technologies for inspection of conduits [22]. They reviewed several robotic technologies (crawlers) that can access and evaluate conduits with diameter ranging from 12 to 120 in (Figure 6a). They also looked into UAS that can perform evaluation of conduit extremities and access larger conduits removing the need for an inspector to approach the structures (Figure 6b).
(a)
(b)
Figure 6: Conduit remote inspection using (a) crawler robot (b) UAS [22]
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