Pre-positioned column sockets improve flatwork and panel construction for tilt-up projects.
Building owners today demand concrete floors of the highest quality. Big-box retailers are highly sensitive to the appearance of floor surfaces exposed in public areas, since cracks, discoloration, and uneven surfaces leave a poor impression in the shopper’s mind. Distributors, warehouse owners, and manufacturers, while not as sensitive to aesthetics, demand structurally sound, consistently level floors for the safe functioning of racking systems and forklift traffic.
Popular building construction methods, such as tilt-up, require the concrete floor slab to be constructed prior to steel erection. In order to secure the steel columns to the foundations, the traditional method has been to leave voids in the floor slab known as column box-outs. These are costly both in terms of labor and materials, present serious trip and fall hazards, add extra joints, and leave an uneven, discolored finished floor surface.
Connect-EZ has developed a device to overcome these issues and increase productivity in tilt-up concrete construction: the Column Socket. Installed prior to concrete floor construction, typically with post-installed concrete anchors, this custom-fabricated device eliminates the need for box-outs, simplifying concrete floor placement and column layout, as well as speeding steel erection while maintaining consistent concrete coloration.
Column Sockets are custom made to accommodate any size or shape of steel column—from tubes to wide-flange—and have been proven to meet OSHA regulations for columns anchored to a baseplate. The sockets are detailed and positioned so that the covers are flush with the finished floor elevation for unobstructed screeding and a blemish-free surface for tilt-up panel casting.
First, column sockets are located on the column foundation and secured with anchor bolts or post-installed anchors. The critical top elevation of the socket—positioning the top of the steel cover flush with the finished floor—is then established with shims and grout.
“One thing that’s unique about this column socket is that it is turned 45 degrees from the way most other devices of this type are, so that the anchor bolts are directly on the column grid,” says Karen Hand, an engineer with Needham DBS structural engineers in Lenexa, Kan. “This helps with getting the bolts and the socket in the correct position.” But, Hand notes, the bigger benefit is that it makes the slab monolithic, especially when there’s an exposed concrete floor, so there is no diamond-shaped column block-out. “We worked on a school where this meant that the columns were then completely hidden inside the walls leaving the slab in the hallway completely clean.”
Hand notes that one issue her firm has run into is determining who pays for the sockets. “The steel erector thinks the concrete contractor should pay for them since they are installed prior to the concrete placement, but the concrete guy feels like they are part of the steel package.” She also notes that most steel erectors are concerned about the usefulness of this device at first. “But once they’ve used it, they really love it.”
Column Sockets provide a simple, safe, secure solution to the challenges of traditional floor slab box-outs, and they satisfy building owners’ demands for concrete floors of the highest quality.