Steel Frame Buildings
In this common multi-story design, steel columns are attached to the foundation with anchor bolts and beams are bolted to the columns with brackets and clips. Often these brackets and holes are pre-welded at the steel fab shop. Built one level at a time, this type of structure is ideally suited for the use of precast concrete stair systems to access each active construction level and provide a high quality, sound-suppressing, finished product.
Castcon Value Added
In a steel frame building, precast stairs are erected as each steel level goes up. This provides a safe work area for the steel erectors and all subcontractors as they access the levels above. Say goodbye to temporary scaffold stairs and wooden makeshift ladders. Castcon can provide inserts for temporary handrails at 4’-0” on center per OSHA guidelines to ensure proper on site safety. No need for touch up painting on the steel. Precast stairs are a finished product.
Open Zee
This stair design is often used in a steel frame structure (this type of stair has an integral landing at the head and foot of the stair). The intermediate landing of the Open Zee must be suspended from the floor steel beams of the structure. The landing that reaches the floor level will bear off of the floor steel. The benefit of using the Open Zee design is that there are only two pieces per level to erect within a stair tower, which saves valuable construction time and offers immediate access by all trades in the stair tower.
S-L-S (Stair-Landing-Stair Design)
In applications where the floor-to-floor level is above 12’-0” height, building codes require that a stair (if not a “switch-back” design) have a mid-level landing within the stair run. The S-L-S design is actually three pieces in one (two stairs with an integral mid-level landing). The S-L-S stair requires support at the head and foot, which is usually a steel beam. S-L-S design offers quick erection and access and helps to reduce the number of bearing locations (due to the design being three pieces in one), thereby also reducing the cost of the steel framing package to the customer.
Half-Z (Tension Rod)
The best method of supporting a precast concrete stair system in a steel frame building is to suspend the intermediate landing from the stair tower framing steel. Castcon prefers a detail in which the hanger steel is run through tube steel cast into the landing edge. The hanger steel is concealed within the stud partition wall once the project is complete and the bearing for the stair system is completely invisible, giving the impression of wonderfully solid, quiet stairs and landings supported by drywall. The floor landings can either be precast slab bearing on the framing steel or cast on the metal deck along with the remainder of the floor slab.
Single Run (X)
Unlike the S-L-S design, the single run stair is for applications up to 12’-0” height floor-to-floor elevations. This design is an economical alternative because two stairwells can occupy one shaft, separated by a fire wall. We see this design most commonly in cities where the real estate is mostly “vertical”. As noted above, the single run stair can be erected very quickly (often 1/2-hour or less for each stair), creating immediate access to the floor levels for all trades. Castcon takes pride in offering an architectural sensibility to a structural product so that the stairs are not only practical but aesthetically pleasing.