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Bearing Pressure under Wood Balcony Baseplate

EngDM

Structural
Aug 10, 2021
754
For a balcony guard, what is the typical assumption for designing the compression zone of a baseplate down to say, a 3ply 2x10? Assume that the torque induced in the 2x10 is restrained, but the baseplate is digging into the 2x10.

Do you just use the same bearing value as sizing a stud wall, but without the geometric factor increases? (4.24MPa for SPF No 1/2 in Canada)? Can I go higher than that if I allow for more crushing of the wood?
 
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Remember, more crushing means more rotation of your joint. A tiny rotation at the bottom can translate to noticeable movement at the top.

I usually us listed compression perpendicular values for this design. Set that as the peak of a triangular distribution with a set anchor spacing, and solve the quadratic to get the shape of the distribution and resulting tension/compression couple magnitude.
 
Remember, more crushing means more rotation of your joint. A tiny rotation at the bottom can translate to noticeable movement at the top.

I usually us listed compression perpendicular values for this design. Set that as the peak of a triangular distribution with a set anchor spacing, and solve the quadratic to get the shape of the distribution and resulting tension/compression couple magnitude.
Good point on the rotation, I'm just trying to find different approaches to make drasted guardrails work. This is like my nth post about this, and the jurisdiction has been pissy lately asking for calcs, and these are the one things that never really calc out well.

Honestly, the headache guardrails cause make me want to just get a load tester involved with a couple assemblies and just go with that approach.
 

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