abdallah hamdan said:
BAretired, I make a detail just to make sure I understand you, does the detail for this stair look like this?
No, my sketch was for a stair framed with steel beams, one of which was cranked in two places, each side or tread #6.
You do not show supports for the stair slab in your latest sketch. Draw a plan of the stair and landings and how you intend to support it.
The sketch below is taken from an article about a precast stair slab which collapsed under the weight of a single worker who was climbing the stair when it suddenly felt "spongy". Fortunately, he was agile enough to save himself by jumping onto a neighboring floor. See thread507-231262 for the complete article.
Location of supports is needed for design purposes. Otherwise, the location of points of inflection are not known. You have not provided the location of supports, which makes me wonder if you believe we are mind readers. Draw a stair framing plan, showing dimensions and where you intend to place supports.
The precast stair below had a span of "X", as shown in the sketch. That makes it a simple span, a very long one with a total of four cranks between supports.
Engineers performing a review of the stair found no fault with design and detailing (see below), so be aware that you are playing with fire with this type of design.