TCH–Precision Scaling for Huge Dry Dock
From our October 2001 newsletter

Quebec City, Canada – In June, Gercom Construction took on a job calling for an unusual degree of control. The MIL Davie shipyard in Quebec City, one of Canada’s largest, planned to repair and resurface a massive dry dock. Working as subcontractor for Les Entreprises Cote C.R.T., Gercom had to scale off exactly 6 in. of worn concrete from the 30-foot-high walls of more than 107,000 square feet of dock. Even a half inch more, and the contractors would have to go to the expense of replacing the concrete.

TCH Cutting Head scales vertical surface.

Two factors shaped the project from the start: the need for exact cutting depth, and a job spec banning any impact of more than 150 joules (approximately 110.5 ft. lbs.). Gercom considered various options—a large crew working carefully with small hand-held breakers, high-pressure water scaling—which were rejected as being too costly and slow. They finally decided on a TCH 40 Rotary Cutting Head, purchased through Denis DeChamplain, Tramac’s Director of Sales-Quebec. The TCH is classed as a 10W impact attachment, making it ideal in sensitive environments where vibrations are a concern.

The TCH is designed for precision operation. To enhance control even further, Gercom associate Robin Prive devised a custom rectangular jig with a vertical track on which the cutting head was mounted. The jig controlled the head’s movement and cutting depth so exactly that as little as 1/16th inch could be removed at a time. The jig was held up to the wall and powered by a Caterpillar 320 excavator on the floor of the dry dock. Work was remote-controlled by an operator standing on top of the dock wall looking down. He could see the depth of the TCH’s cut into the concrete and gauge speed and down-pressure with great accuracy.

The job began in mid-June and was completed in early September, at a production rate of nearly 2 cubic yards per hour. The TCH produced material less than 2 in. in diameter, eliminating the need for secondary breaking for recycling. Mike Pietroniro of Tramac’s Canadian office tells us that Gercom is very pleased with the unit, and can see many applications for it in future.