1 inch diameter handrail post

[Gopher13]

Has anyone ever used a 1 inch diameter (1.32 inch outside diameter) stair handrail post. In the past I have used 1.5 inch diameter posts. If I run a quick calculation with a 200 pound point load and a 3.5 foot tall post I get a bending stress of 55 ksi over 1.5 times yield stress (assuming Fy=35 ksi). Is there load sharing going on with the adjacent posts?

I appreciate any comments. Thanks in advance!

 

[SlideRuleEra]

There is load sharing if the horizontal load is applied between posts, but the load can be applied anywhere along the length of the rail. This includes directly at, or adjacent to a post. In that case, there is no meaningful load sharing until the loaded post has yielded.

1910.23(e)(5)(iv)
The mounting of handrails shall be such that the completed structure is capable of withstanding a load of at least 200 pounds applied in any direction at any point on the rail.

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[jayrod12]

There was a previous discussion about this and it was rather lengthy. It went into the discussion about load sharing.

I still feel that 1" posts are too narrow however.

Edit: found it thread507-405072

 

[XR250]

if the top rail is stout enough, there should be meaningful load sharing for the point load, however, the 30 or 50 plf req'd distributed load could render that moot.

 

[thaidavid40]

I have been on plenty of stairs and platforms with substandard railing posts installed, and it is a scary feeling when you lean on them and they do not present the stiffness you are expecting. Perception has a powerful effect on reality. Even if it could theoretically hold up by some form of wide load redistribution, I would be afraid to use such a skinny post, and probably afraid to lean on it as well!
Dave

Thaidavid

 

[Ron]

Most posts are spaced at 48". If you decide to use such a small post, space them closer. As for the 50plf, if your posts are spaced at 48", that's the same as a 200 lbf concentrated load on the posts.

Yes, there is load sharing, but as thaidavid40 noted, there is a need to design for "pedestrian comfort", just as you would for bar grating and other potentially high deflection items.

One thing that significantly stiffens the rail is to make sure it is properly anchored at the bottom of the stair section. At terminating sections, this is a bit difficult to achieve. I use a two place anchorage on stair sections that I design. The last (first) post is welded to the end of the stringer along its full depth, to you don't have bending in the stringer flange. Next, the ADA return is anchored to the concrete. This gives much less deflection at the bottom and thus more perceived stiffness to the entire rail.

 

[msquared48]

Load sharing may occur, but you still have to deal with the end post where there is little sharing.

Mike McCann, PE, SE (WA)

 

[Bagman2524]

Load sharing between posts is discussed in NAAMM AMP-510. The load can typically be reduced by 20%. I've never been able to 1" diameter posts to work. 200 lbs x 42 inches x 0.8 = 6,720 in-lbs.

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