Sometimes conventional concrete saws or jackhammers can't be used to remove concrete from an existing structure. Dominion Construction Co. Ltd. ran into such a case in the construction of Toronto Dominion (TD) Centre, an office complex built in Winnipeg. The developers decided to erect the TD Center around an existing office building. Demolishing the first 30 feet of former office space made room for the TD Centre facade. But foundation plans called for two caissons to be placed in this area, requiring cutting a 15x5-foot hole in the concrete floor slab of the former office space. Jackhammers couldn't be used because vibrations could disturb sensitive telecommunications equipment only a few feet away. Conventional concrete saws couldn't be used because they required too much water which would damage wires and cables.
Enter Di-Tech Wire Sawing Systems, Inc., of Winnipeg. This contractor had a wire concrete saw that could cut the concrete. The saw uses a wire studded with diamond beads. A pulley system connects the wire to a power unit, which whips the wire over the concrete at up to 80 feet per second. It cuts through concrete, reinforcing steel, I-beams, and anything else in its way, cooled by relatively low-flow water jets.