Some time ago, a colleague called to get my opinion on the use of TV cameras for underground inspection of drilled shafts.  His query related specifically to relatively tight working areas and “in the dry” conditions. After pressing him to elaborate further on the context of his question, I discovered that he was weighing the benefits of TV inspection versus human entry into the drilled shaft excavation site. 

This conversation is indicative of a larger movement that has been afoot for the past few years that seeks to discourage - or even eliminate - personnel from entering drilled shafts to clean or inspect the bottom.  Although there are many reasons as to why TV inspection is increasingly favored over human inspection, there are two fundamental reasons behind this push for TV inspection.  First, some contractors believe that they can achieve better, faster and cheaper results if the inspecting engineer simply stays out of the way.  Second, some contractors and engineers are concerned with the liability/insurance issues that come into play if anything was to happen, for whatever reason.  While there is a degree of truth and merit behind both of these reasons, it is my unwavering belief that human inspection must be favored over TV inspection in certain conditions, and that human entry into the excavation site is a necessary part of the inspection process that cannot be eliminated.