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concentrated load of edge of beam flange

concentrated load of edge of beam flange

concentrated load of edge of beam flange

(OP)
I have a concentrated load of 5000 lb. on the edge of a beam.I am trying to calculate/estimate what localized effect it has on the beam flange. Torsion on the overall beam is low as per my calcs. But I want to verify that there is no localized stress or deflection concern in that limited area of the beam flange.
I looked at coefficients for loads on "plates" considering 3 edges "fixed" - 1 at the web,and the other 2 some distance away from the load foorprint and one free edge at the flange edge.
But that really isnt the actual situation as the "edges" perpendicular to the bean flange edge arent really fixed but just continuous. I looked at it also with 45 degree distribution thru the flange to the web and it's fine as far as bending stress. But even that is not really the actual condition.
Anyone ever check this condition? Is there some simplified way to verify that the local area of the flange is ok?

RE: concentrated load of edge of beam flange

The simplest (and conservative) way is to distribute the load at 45 degrees over to the flange radius (k1), and check flange bending over that distributed width at 0.75Fy. Since "b" (the distributed flange width) is equal to twice the bending arm (unless you're near a flange end) the required flange thickness would be square root of(3P/(0.75Fy)) where your P = 5000 lbs.

RE: concentrated load of edge of beam flange

Regardless, I would still install a bearing stiffener.

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: concentrated load of edge of beam flange

I'm with Mike..  See his motto. it certainly applies here.

RE: concentrated load of edge of beam flange

(OP)
spats thanks  That is one of the ways i looked at it and I get about 7 ksi which is plenty good compared to 27 ksi. I guess Im still a little concerned with deflection at the fee edge of the flange but not sure how to estimate/caculate this. I may be overthinking this,but I am thinking if it deflects some then how willthat interact with the compressive stress in the overall beam flange from the overall beam load.

RE: concentrated load of edge of beam flange

Redun... yes, you're over-thinking it, in my opinion. "Deflection" will be negligible.

RE: concentrated load of edge of beam flange

Don't forget to check the web for the moment as well!  Most (if not all) beam shapes have a thinner web than flange.  The flange may work in bending, but the moment carries through the bulb at the flange/web interface into the web.

We investigated a case where the entire top flange of a beam rotated because a plastic hinge had formed just below the bulb...


-5^2 = -25  winky smile

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RE: concentrated load of edge of beam flange

How to is just easy today with FEM tools. It is a matter of a simple extrusion and use whatever the program provides to place the factoree loads on the meshed part. Since steel, a Von Mises stress will inform you immediately of any weakness there, and even with an elastic setup if you are seeing there any plastification causing the local failure. You may model the whole beam or a part of it trying to mimick the solicitations present (otherwise the product stresses won't be representing the situation).

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