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WOOD FLOOR VIBRATION

WOOD FLOOR VIBRATION

WOOD FLOOR VIBRATION

(OP)
I have a condition where a wood framed floor is spanning 14'-8" between masonry walls. I am considering using No. 2 Southern Pine 2"x12" floor joists at 16" c/c. The ceiling will be drywall and the floor will have 3/4" T&G plywood glued and screwed. Have an area with no walls below or above to help with damping.

Minimal mechanical equipment and hardwood flooring. Is there a procedure for checking vibration. Thanks for any help.

RE: WOOD FLOOR VIBRATION

What is your deflection on that?  

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: WOOD FLOOR VIBRATION

I actually just attended a seminar on this and I will try to post the info on Monday. However they suggested deflections tight - around LL/480 and TL/360 (if I recall correctly). Also they said their tests did not find that cross bridging or blocking helped but I can tell you from experience that it will stiffen the floor. They also said that testing done in Canada led to the same conclusion.  

EIT
 

RE: WOOD FLOOR VIBRATION

For almost all cases we shy away from using sawn lumber for floors. We almost always use TJIs as they are straighter, truer, and less likely to shrink. You may want to consider using engineered lumber, I think it is a far superior product for floors. With that said, iLevel has a floor performance rating for perceived vibration. I think it is based on surveys and not engineering science but we typically use it as an additional serviceability check instead of just using deflection.   I too try and limit floor deflections to L/480 and L/360 for wood floors in custom homes.  

RE: WOOD FLOOR VIBRATION

ironically, I have a large wide open living area in my house with the exact same construction you described with the sheathing being Advantech brand.
I can jump on the floor and get minimal vibrations, but if my three yr old runs across the floor, she can get into cadence with the floor frequency and the floor wobbles noticeably. I have had adults run across the floor and not noticed it anywhere near as much. My three yr olds weight and impact can set the floor off.

AISC design guide 11 is for floor vibrations and natural frequencies. ?It's possible that the procedures could be adapted to wood.

I dont have anything handy here.  

RE: WOOD FLOOR VIBRATION

iLevel has a free program called "Forte" that will help quantify some of the bounciness ideas...

RE: WOOD FLOOR VIBRATION

(OP)
Thanks for the input. Just what I needed.

RE: WOOD FLOOR VIBRATION

(OP)
Yep.

RE: WOOD FLOOR VIBRATION

@ jdgengineer

TJI's are indeed straighter and create a better, quieter floor. However, in my area if fire fighters know that the floor is made from TJI's they will not go in the building. Just a thought to consider...

Great spirits have always encountered violent opposition from mediocre minds - Albert Einstein

RE: WOOD FLOOR VIBRATION

LVL is the norm for floor joists where I am.  Big softwood trees are scarce here.

RE: WOOD FLOOR VIBRATION

I tend to agree with the firefighters.  There is not much meat in a TJI to resist the progress of a fire once it starts.  Same goes for light wood trusses made of 2x4's and truss plates.  We have had a number of fires in our area over the last year or so and people are starting to question the adequacy of the building code respecting fire protection.  I question it too.

BA

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