Top 10 Keyhole Uses For Smart Construction

February 2014, Vol. 69 No. 2

6. Connecting service laterals
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Connecting a new service lateral through a keyhole to a main that had been installed using a trenchless technique or rehabilitated is a key element in helping to keep what was supposed to be a “no-dig” or “trenchless” process trenchless… or at least as close to trenchless as possible. After a new main is directionally drilled and the new pipe is pulled through, the service laterals can be reconnected through a keyhole using bolt-on or electrofusion saddles. The pavement core can then be reinstated as an almost invisible permanent pavement repair rather than scarring the neighbourhood with a checker-board of small, unsightly, square-cut excavations that will subsequently need to be milled and overlaid.

7. Valve box repair or replacement
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Installation of a valve box or test station using the keyhole process results in a precise, circular-cored opening and a perfectly flush finish with the surrounding roadway. There are no overcuts one typically finds when using a road saw and a jack hammer, and the smaller cored openings can be sized to exactly fit the new valve box. This application works for both gas and water utilities. For valve boxes that have sunk, or that have been paved-over, the coring and reinstatement process is also a perfect solution when these need to be reset level with the surrounding pavement.

8. Pipeline inspection
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Insertion of cameras for pipe integrity inspections or to identify and map the location of bell joints in advance of keyhole bell joint repairs can be done through an 18-inch diameter keyhole into a live gas main. The cameras can travel at least 150-feet in each direction in a cast iron or steel main and 250-feet in each direction in a PE pipe, enabling you to inspect the condition of the pipe and locate and map joints and fittings.