Allowable deflections for Residential Floor Beams
Allowable deflections for Residential Floor Beams
(OP)
I have been pondering allowable deflection limits for our residential design standards for high-end residential *FLOORS BEAMS*(wood framed with LVL, glu-lam, and steel beams). I am trying to develop a list of criteria for younger engineers, and I would appreciate some input from some of y'all. Over time, I have tended toward the following limits for these expensive homes (using the minimum of any of the following):
Limit 1: Live load deflection less than L/360 for L < about 8 ft, L/480 for longer spans.
Limit 2: Total load deflection less than L/240 for L < about 8 ft, L/360 for longer spans, but never more than 3/4".
Limit 3: Beams parallel to a wall below: Total load deflection < 2D/240 max, where D is the distance from the beam to the adjacent wall.
Limit 4: Any beam supporting masonry: Total load deflection less than L/600.
I would appreciate some of your thoughts on these criteria, and any experience you've had with other types of deflection limits. Thanks!
Limit 1: Live load deflection less than L/360 for L < about 8 ft, L/480 for longer spans.
Limit 2: Total load deflection less than L/240 for L < about 8 ft, L/360 for longer spans, but never more than 3/4".
Limit 3: Beams parallel to a wall below: Total load deflection < 2D/240 max, where D is the distance from the beam to the adjacent wall.
Limit 4: Any beam supporting masonry: Total load deflection less than L/600.
I would appreciate some of your thoughts on these criteria, and any experience you've had with other types of deflection limits. Thanks!






RE: Allowable deflections for Residential Floor Beams
See "Technical Note on Brick Construction, 31B" at this link:
http://www.gobrick.com/html/frmset_thnt.htm
For an upscale structure you may want to consider L/1000 or 0.3" (whichever is less). See this article:
http:
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RE: Allowable deflections for Residential Floor Beams
Your Limit 3 is an important check that is often overlooked.
RE: Allowable deflections for Residential Floor Beams
RE: Allowable deflections for Residential Floor Beams
Mike McCann
MMC Engineering
RE: Allowable deflections for Residential Floor Beams
Mike McCann
MMC Engineering
RE: Allowable deflections for Residential Floor Beams
Also, what is the reasoning behind the LL deflection of L/600, nte 1/4" for the concrete overlay? Some cracking would be OK, I guess...are you just trying to keep the overlay from cracking too much and peices working loose?
Thanks!
RE: Allowable deflections for Residential Floor Beams
Mike McCann
MMC Engineering
RE: Allowable deflections for Residential Floor Beams
www.SlideRuleEra.net![[idea] idea](https://www.tipmaster.com/images/idea.gif)
www.VacuumTubeEra.net
RE: Allowable deflections for Residential Floor Beams
RE: Allowable deflections for Residential Floor Beams
RE: Allowable deflections for Residential Floor Beams
RE: Allowable deflections for Residential Floor Beams
RE: Allowable deflections for Residential Floor Beams
For the "newer" megabath tubs and inside suana's - same psf limit? Or do you design that floor uniquely knowing what the spa/pool weight of people + water + spa weight will be?
RE: Allowable deflections for Residential Floor Beams
Mike McCann
MMC Engineering