Allowable Wood Arch Deflection
Allowable Wood Arch Deflection
(OP)
Anyone know any good guidelines for vertical and lateral deflections of the main menber of a semi-circular wood arch section? Unbalanced snow load is killing me here!
Mike McCann
MMC Engineering






RE: Allowable Wood Arch Deflection
1994 AITC Timber Manual, 4th Edition says "Specific deflection limitations forarches have not been generally established becaseu this is a function of the intended use."
Sorry can't help,
Good luck and let us know what you find/decide.
Dermott
RE: Allowable Wood Arch Deflection
RE: Allowable Wood Arch Deflection
I was wondering about linking the deflection to the "snap-through" mode of failure as in Timoshenko and Gere, but that's idea's way out on a limb and too complicated for this problem. I will keep looking. Thanks. You have confirned that I am not crazy...yet.
Mike McCann
MMC Engineering
RE: Allowable Wood Arch Deflection
It is mainly a problem of how much deflection can the attached finish material handle. A retired engineer I know with over forty years of experience in wood design, indicated before computers generally arch deflections were not calculated because the process was very time consuming and most people did not have a lot of faith in the final results.
He indicated the engineers he worked with thought that the decking would reduce the arch deflections. In some case, where he ran the numbers, he thought the results were close to what he observed in the field. In addition he indicated that he saw a lot of cmu walls that were not plumb because of arch deflection.
RE: Allowable Wood Arch Deflection
Try this, may not be right on but may give you some ideas.
Good luck,
Dermott