Floating Stair fixing detail
Floating Stair fixing detail
(OP)
Good Day,
I am designing a floating stair, see attached drawing from architect. The flange channels used to form the treads must fix into a 230mm concrete wall. Now this must be a fixed connections, and no bolts and nuts can be visible. I am thinking of leaving openings in the wall (not that easy to do accurately as home builders can be quite unrefined at times) and then have an endplate welded to the end of the channels. This then gets fed through the hole in the concrete wall which will be oversized. The space between the steel channel and the wall can then be packed with a lean mix concrete. This should give a fixed connection to the cantilever.
Is there a better way this connection can be detailed? The easiest would be for the wall to be cast and the sections then post fixed, that way the location of the openings mentioned above is not important, and the tread locations can be neatly set out on the wall surface. But now how does one make a fixed connection to the wall that can be hidden or covered afterwards?
Thanks
I am designing a floating stair, see attached drawing from architect. The flange channels used to form the treads must fix into a 230mm concrete wall. Now this must be a fixed connections, and no bolts and nuts can be visible. I am thinking of leaving openings in the wall (not that easy to do accurately as home builders can be quite unrefined at times) and then have an endplate welded to the end of the channels. This then gets fed through the hole in the concrete wall which will be oversized. The space between the steel channel and the wall can then be packed with a lean mix concrete. This should give a fixed connection to the cantilever.
Is there a better way this connection can be detailed? The easiest would be for the wall to be cast and the sections then post fixed, that way the location of the openings mentioned above is not important, and the tread locations can be neatly set out on the wall surface. But now how does one make a fixed connection to the wall that can be hidden or covered afterwards?
Thanks
RE: Floating Stair fixing detail
I have another idea, but this could get tricky with the analysis and detailing. Can you design a stringer (out of heavy tube steel) that looks like this "<". This stringer would carry all the loads...torsion, bending and axial forces (like a truss). Each stair tread would cantilever out of this stringer.
RE: Floating Stair fixing detail
RE: Floating Stair fixing detail
So just need to design the endplate thickness.
RE: Floating Stair fixing detail
BA
RE: Floating Stair fixing detail
But I agree with BA, a precast end plate and site weld the treads to the plates is the way to go. I don't know the design loads but think you would almost struggle with chemical anchors.
RE: Floating Stair fixing detail
RE: Floating Stair fixing detail
I don’t know quite how you are going to fabricate the tread boxes and then clad them with solid wood. Will expansion and contraction be a problem with wood joints, etc? You might consider tipping the free ends of the treads up a few degree to compensate for cantilever deflection. You might also taper the treads from 5" at the wall to 3" at the free end. Also consider, that at each free corner you provide a vert. connection (rod or 1" sq. tube, or some such) to the tread corner above and below so each loaded tread shares its loading. You may not want to interconnect the treads and glass handrail system because of the differential deflections. And, don’t forget the fairly sizable handrail loadings (lateral and vert.) required by codes, the Arch’s. design looks a little light. The landing looks much too light also. I’d review these stairs as they relate to your building code, sometimes an Arch’s. pipe dreams and the building code are not exactly in synch.
RE: Floating Stair fixing detail
RE: Floating Stair fixing detail
RE: Floating Stair fixing detail