DM 340 and DS 450
WV DOT worked with Brayman Construction based in Saxonburg, Pa. as general contractor on the project. Brayman turned to Concrete Coring Company, Butler, Pa., as a subcontractor to complete core drilling of 32, 20" deep holes over the top of existing anchors on the bridge piers, and flat sawing 4,700lf of the deck for removal. Adam Lesseski, Project Manager, and his team used multiple Husqvarna FS 8400 flat saws and complementary blades for the flat sawing portion of the project. For the drilling component, they used two Husqvarna DM 340 drill motors, a 230V and 115V model. They also used two new drill bits, the B1410C as a starter and B1115C to achieve the required depth, also from Husqvarna.
not a lot of head room.
The set-up and drilling were very complex. In addition to rain, the set-up of the drill rigs was complicated by large steel beams, which were located only 48" above where the holes needed to be drilled and allowed for only minimal space to position the rig. The small base on the DS 450 drill stand and light weight enabled the rig to fit into the space without too much hassle. The drill bits were located over the center bolt and needed to work through 2 mats of 1-1/4" rebar, tire wire, and mesh mat at the bottom of the holes – exactly where the cores needed to be snapped off. Lesseski said, “The drill bits worked great and were extremely fast and consistent while drilling through the excessive amount of steel. The B1410C and B1115C held up like nothing we have seen before.” The quick disconnect feature on the drill motors made it easy to remove the motors from the stands to quickly and easily move them to the next location. The drill motors provided enough power and stability to keep the bits turning and cutting through all the materials at an above average rate.
The motors and bits worked together to complete all 32 holes in 16 hours, which Lesseski considered to be a record time under the conditions.