On Friday, July 19, 2002 the last day of a grueling week of the busiest month of the year, Ohio Concrete Sawing & Drilling received a phone call from Fru-Con at 4:30 p.m. Fru -Con needed two holes drilled, each approximately 70 feet deep and two inches in diameter. At the moment, the proper equipment to perform such a sizeable task was at one of Ohio Concrete’s other branches. Therefore, they immediately sent someone to their facility in Columbus, Ohio to retrieve special core bits allowing them to drill to the desired depth. At 7:00 a.m. the next day, Saturday, operators began drilling the first 2” holes on the Maumee River Crossing.

CSL testing has become an acceptable manner of determining the integrity of concrete in the last ten years. It is the first step in determining the integrity of the concrete after the foundation pier is complete. However, this method of testing is not always successful due to slurry interfering with the electric pulse. Therefore, core drilling is a secondary test to CSL. Core samples are taken to determine if there are any voids present within the foundation pier as well as to demonstrate compressive strength at different intervals in the caisson.

Because a core drill allows the operator to drill only as deep as the bit, Continental tubing is used. Continental tubing is hollow tubing threaded on each end and allows the drill operator to drill very deep holes without continually retrieving the cores. When the core drilling is complete, the 2” core pieces are removed from the tubing and aligned in order from top to bottom. Then, the pieces are tested to make sure the foundation pier is solid and the concrete meets the Ohio Department of Transportation’s specifications.

Fru-Con has been very pleased with the service of Ohio Concrete. Matt Hogan, a manager for Fru-Con, said, “Ohio Concrete Sawing’s service to this project has been outstanding both in the timely response to requests to perform the coring as well as the experience shown while working on site.”