Core drilling 12" holes in asphalt in Charlotte, NC.
Every once in a while we get asked to do some misc. ironwork. This type of work has gone hand in hand with our normal job of core drilling as sometimes the products and or services are closely related. Often handrails, bollards, bike racks, and other misc. metalwork requires that core drilling is involved.
Since our first major project back in 1999. Which was the majority of the installation of all the misc. metal throughout the Concord Mills Mall located in Concord, North Carolina. We have developed many techniques for installing ornamental ironwork of some type which of course core drilling and installing 6-inch metal schedule 40 bollards. Over the years we have drilled 10-inch, 8-inch holes for bollards but eventually, we found that Twelve-inch holes for bollards work best, maybe even 14-inch when the bollards are to be set in asphalt. The larger core drill hole sizes allow more concrete to be poured around the six-inch steel pipe so it is harder to knock over.
Once we cored through the asphalt there was gravel and mud, which meant it was time to get out the post holes diggers and breaker bar so that we could make the hole 24-inches deep, hoping to get as much concrete around the pipe for a good foundation for the pipe to adhere too.
Digging in the dirt is not what we like to do,
in fact, I hate it, but when you got work to do, well you know, you have to do it. So after the dirt was extracted and everything was ready we set the bollards into the holes. What you can see in the picture is the layout of the installation. I always make a circle for where the core drilling will take place. Many times center of the hole is what we use to mark the circumference of the hole to be drilled, and of course a template of the correct size. To our surprise, the asphalt was only four inches deep, which made for more post-hole digging than we like, yuk! The holes had to be at least 2 and a half feet deep, so it took a little while for the digging to get complete. But in the end, it was done. The total number of bollards was 5. They were being installed to protect the transformers for the extra storage facility on Wendover Ave, Charlotte, North Carolina. Right across the street from Sir. Gus, which is a small restaurant I have always wanted to try, and it turns out the wait was worth it as they do have delicious food.
Sharon Rd is still alive, who knew.Was any building code involved?
Apparently, it was as the bollards were placed more than 5 feet from the transformers as the grey boxes in the picture. In general, they were installed 60" from each other to make everything up to snuff and presentable. The depth of the bollards below grade was 30 inches. A ratio of more than 30 percent of the height was buried to allow for impact. We painted them safety yellow and filled the metal tubes with 5000 psi concrete for extra sturdiness.