Connection Idea Needed

[CTW]

I'm looking for a simple method of connecting a single HSS column to the center of a landing (C10) steel stairs. Landing size is 36" x 36". Entire stair system is braced against lateral movement.

What I had in mind was to run another C10 (perpendicular to the stringers) in the middle of the landing, weld a plate to the bottom of the C10 at midpoint. This would allow the column to be erected, then bolted to the plate on the C10.

Any other suggestions?

 

[Lutfi]

You did not provide information on the use of the stair nor the landing.

Your concept/idea should work. I would avoid single column under the stair landing unless it is absolutely necessary. I call this design a single point failure in the making. Consider the lateral stability of the stair and landing? You don not want users of the stair to get uncomfortable with flimsy and shaky stair. Consider using two columns and support the stair stringers at each end. With single column you need to consider unbalanced stair loading plus any lateral loads.

I question the landing being 36” by 36”!! Most US Codes (SBC, UBC, IBC, BOCA) that I am familiar with require, as a minimum, the stair landings to be as wide as the flight of stairs. If you consider one flight width and I am assuming users will need to transition to another flight, the landing should be twice as wide as the flights plus clearance for interior stringers.

Good luck.

 

[CTW]

Good point about using one column. I'll use two. The 36" x 36" landing is satisfactory since the stairs are 36" wide. I've tried to depict the flight arrangement below. Users will go up one flight and then turn 90 degrees to the right to ascend to the top platform.

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[jrmack]

You could weld a 36" C10 c/w clip angles onto the face of the HSS, and bolt connect the stringers to the 36" C10. The HSS would have to be strong enough to handle any unbalanced loads.

If this is a 90 degree stair landing, your plate (or clip angle) on one side of the HSS would work with one of the outside stringers, or two plates (or 2 clip angles) with both ouside stringers (corner post). The inside stringers would frame into an outside stringer and last one to an inside stringer.