Vibrating wood floor system
Vibrating wood floor system
(OP)
A prospective client has a floor system (2x10" lumber @ 16" o.c., joist span 12 ft) that is vibrating (vertically) frequently and for hours at a time. The source of the vibrations is unknown. He had somebody measuring the frequency, but they couldn't tell what caused the vibrations.
While there are analytical methods for steel joist floor systems, I didn't find something similar for wooden floors.
Does anyone have an idea how to dampen/mitigate the vibrations?
A common sense approach rather than analytical?
Any input is appreciated.
While there are analytical methods for steel joist floor systems, I didn't find something similar for wooden floors.
Does anyone have an idea how to dampen/mitigate the vibrations?
A common sense approach rather than analytical?
Any input is appreciated.






RE: Vibrating wood floor system
is the house in one of those "mystery spots" along popular tourist routes ?
is there well drilling going on nearby ?
add some weight to the floor ?
RE: Vibrating wood floor system
I would suggest trying to locate the source of the vibration before blindly trying to solve the problem.
RE: Vibrating wood floor system
Use resonance as a guide of the origin, when come to your floor, the vibration comes near the frequency that was made to be investigated, so movements at this frequency should be given priority as likely source.
RE: Vibrating wood floor system
The atc put out a guidance note on timber vibration though I am not sure how helpful it would be.
The fundamental are still the same for all materials so I suggest that you research vibration in general to get a handle on things.
Modern research has shown that the key is usually the level of damping and the fact that this continues for several minutes indicates to me that this is likely a large factor.
The worst thing you can do is recommend a solution that does not fix the problem so make sure you understand the cause before trying a generic solution.
RE: Vibrating wood floor system
You might try blocking between a couple of joists to see if that helps - might - might not.
RE: Vibrating wood floor system
Remember that if you add weight, it will not dampen the system, it will only change the frequency (lower).
If the problem is from rotating machinery, as suggested by Mike, adding weight may or may not solve the problem. There may be a number of excitation sources and if you add weight and happen to resonate with one of these other frequencies, you could end up making the amplitude (and stresses) much higher. I don't have lots of experience with wood structures, but I think that would be a problem.
As for sources, I'm more inclined to go with something going on inside the building, as suggested above, but to throw out a wild postulation -- how about vortex shedding off of some horizontal portion of the building due to sustained winds? The roof, maybe? Is this located anywhere between Amarillo and Fargo?
Engineering is not the science behind building. It is the science behind not building.
RE: Vibrating wood floor system
ZCP
www.phoenix-engineer.com
RE: Vibrating wood floor system
Mike McCann
MMC Engineering