folded stair in timber
folded stair in timber
(OP)
Good Morning,
Does anyone have experience designing a folded stair in timber? Is it doable?
See attached picture for reference
http://st.houzz.com/simgs/6361cf11015f06ab_4-2130/...
Thanks in advance
Does anyone have experience designing a folded stair in timber? Is it doable?
See attached picture for reference
http://st.houzz.com/simgs/6361cf11015f06ab_4-2130/...
Thanks in advance






RE: folded stair in timber
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RE: folded stair in timber
RE: folded stair in timber
RE: folded stair in timber
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: folded stair in timber
I've done 3 of these.
RE: folded stair in timber
RE: folded stair in timber
RE: folded stair in timber
I was seeing a concrete or CLT wall and some sexy European connectors the exact nature of which I am currently uncertain.
That's my guess too. Maybe some vertical plates welded to the horizontal ones and providing locations for button-ish support.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: folded stair in timber
RE: folded stair in timber
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RE: folded stair in timber
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RE: folded stair in timber
Doesn't seem possible for long span condition in wood alone unless you can provide some intermediate supports.
RE: folded stair in timber
I look at that lovely modern staircase and my first thought is 'my.... that's a lot of glass to keep clean'
RE: folded stair in timber
That is a sweet bit of steel fab. Having recently personally fabricated a welded steel stair to a mezzanine I appreciate what that welder had to do to control any distortion.
RE: folded stair in timber
RE: folded stair in timber
Yes, the fabrication was sweet. They used the cut-outs to control it some, and the treads and risers were just a couple of bent plates, folded to follow the layout of the cut-out pieces. Basically we ended up with two flanges and four webs, zig zagging their way up.
Here are some pics of that (attached).
I had some fun with the analysis. I use Visual Analysis for all my work. It's produced by a company in Bozeman MT called IES. I would encourage anyone to check it out. Incredibly intuitive and very versatile. (I have no connection to the company. I just like the product A LOT).
Anyway, I started with simple deflection limit of L/720. After fabrication, deflection was fine (very close to the analysis numbers) but vibration was very bad. Analysis indicated Natural Frequency to be in the "very perceptible" range and sure enough, it was! The program allowed me to try several different strategies to "muddy up the stiffness" and in the end we anchored the bottom better and added a small prop near the base, essentially creating some fixity at the bottom two treads.
RE: folded stair in timber
The analysis was with RISA 3d and simply looked at the deflection at the end of the tread cantilever with a 300 lb. load - tried to keep it very small.
The tread frames were ultimately infilled with a glass tread surface with LED lights at the root of the cantilever.
After it was completed I stood on the treads and walked up the stairs - a bit of "bounce" or flex as you walked if you were going up near the end of the cantilever.
Probably more than I would have liked but not too bad. If you walked up the center there was no significant bounce.
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RE: folded stair in timber
Put that fabricator's phone number in your speed dial list.
It is a great thing when engineer and fabricator work closely to jointly create a great end result.