design check of handrail post embedment 1

[samdamon]

I am looking for literature references about how to check the strength of a masonry or concrete support for a handrail post. Google searches of this site and also of the net did not yield anything useful.

The moment and shear at the base of a laterally loaded 42" high handrail post have to be dissipated into the concrete or masonry support, and I am trying to rationalize the triangular stress distribution on the support material and required embedment depth of the post. Its not a problem that appears solvable in one or two simple hand calc iterations. I can deal with edge distance issues etc if a stress distribution can be estimated. Has anyone dealt with this problem?

 

[jike]

Wouldn't it be similiar to an embedded pole (laterally loaded) in soil?

 

[haynewp]

I have used an equal tension and compression triangle split at mid-depth, solve for the couple required acting at the centroid of each triangle and from that you can find the max stress at each triangle. But there may be a more exact stress distribution referenced somewhere.

 

[graybeach]

I use rectangular stress distribution with the magnitude of the stress being phi(bearing)times 0.85f'c against factored loads.

 

[samdamon]

Replies were helpful. If we think of the post as a very long cantilever, it will have two opposing but unequal forces at the embedded end providing resistance. Because it's a cantilever, I would expect the stress on the support material and force resultant near the top of the embedded post end will probably be greater than same at the bottom end. If using a straight line stress distribution equal to the max allowed bearing stress, the depth of the stress blocks at top and bottom of the embedded post end can be at least approximated, and that allows me to keep going. Its rough but probably close enough. Anyway thanks and Happy New Year.