Vibration Design Criteria Residential Gym
Vibration Design Criteria Residential Gym
(OP)
We are working on the design of a large "pool house" structure. It will be approximately 22,000 sq ft, 5 stories tall (2 above grade, 3 below). The top level has an approximately 3,000 sq ft weight room / exercise area. The floor span is ~33'. Our current design consists of 2 1/2" topping slab over w2 deck with heavy W16x composite beams at 8'-0" oc (coffered architectural ceiling dictated depth and spacing).
The current design framing design easily meets moment demands and provides an L/700 total load deflection (~1/2"). The vibrational acceleration criteria is about 3% g and a typical floor bay has a natural frequency of around 7 Hz.
Per AISC Design Guide #11 we are targeting <5% g for acceleration for typical residential / office walking criteria. We easily meet this requirement. We are also looking at the rhythmic motion criteria which dictates a minimum floor frequency of 9-10 Hz for a weight room mixed with aerobic exercises.
My gut says our floor is fine and that this criteria would be more applicable for a large commercial gym with 100s of people rather than a smaller gym which may only have 5-10 people working out. But as we are not meeting the frequency criteria i thought it was worth a second opinion. Ultimately, we will present our findings to the architect and owner to make the decision of pursuing higher frequency floor is worth the added cost and architectural impact. It would require stiffer (deeper) beams which will impact floor height below or possible moment connections (very expensive) to try and engage the backspans of the beams.
Ive also wanted to get an opinion of the structural deck below a weight room. The concrete will be covered with exercise flooring which should help soften impact loading. How have you typically designed the concrete? Do I need to be concerned with localized crushing? Per verco the deck is rated for 399psf superimposed loading with our span which should be more than adequate. The topping will be reinforced with #3 bars at 12-18" oc.
Any thoughts would be appreciated!
The current design framing design easily meets moment demands and provides an L/700 total load deflection (~1/2"). The vibrational acceleration criteria is about 3% g and a typical floor bay has a natural frequency of around 7 Hz.
Per AISC Design Guide #11 we are targeting <5% g for acceleration for typical residential / office walking criteria. We easily meet this requirement. We are also looking at the rhythmic motion criteria which dictates a minimum floor frequency of 9-10 Hz for a weight room mixed with aerobic exercises.
My gut says our floor is fine and that this criteria would be more applicable for a large commercial gym with 100s of people rather than a smaller gym which may only have 5-10 people working out. But as we are not meeting the frequency criteria i thought it was worth a second opinion. Ultimately, we will present our findings to the architect and owner to make the decision of pursuing higher frequency floor is worth the added cost and architectural impact. It would require stiffer (deeper) beams which will impact floor height below or possible moment connections (very expensive) to try and engage the backspans of the beams.
Ive also wanted to get an opinion of the structural deck below a weight room. The concrete will be covered with exercise flooring which should help soften impact loading. How have you typically designed the concrete? Do I need to be concerned with localized crushing? Per verco the deck is rated for 399psf superimposed loading with our span which should be more than adequate. The topping will be reinforced with #3 bars at 12-18" oc.
Any thoughts would be appreciated!






RE: Vibration Design Criteria Residential Gym
RE: Vibration Design Criteria Residential Gym
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RE: Vibration Design Criteria Residential Gym
Unless the homeowner is a powerlifter and is regularly dropping 400lbs of steel on the floor after a clean and jerk then it is unlikely to be a problem.
My gut, however, is that 2 1/2" topping may be a little light for weight room impacts. Might wanna go with 4" in that area.
RE: Vibration Design Criteria Residential Gym
Has anyone put a weight room on metal deck before? How did you asses minimum concrete topping thickness?
RE: Vibration Design Criteria Residential Gym
RE: Vibration Design Criteria Residential Gym
The verco catalog isn't very helpful with concentrated loads. Basically says to analyze per engineering principles.
I could review the topping for punching shear ignoring the deck below and check to see if it can span the distance between flutes for moment / shear.
Any other thoughts?
I'm also not entirely sure of the location of the equipment and would like to have flexibility to bolt down anywhere on the slab as necessary. Seems like a thicker topping slab would be a good idea for this as well.
RE: Vibration Design Criteria Residential Gym
RE: Vibration Design Criteria Residential Gym
RE: Vibration Design Criteria Residential Gym
We could also entertain slip critical bolts for these connections. I'm not sure how much that would help with end fixity as we wouldn't engage the flanges, but may help a little.
RE: Vibration Design Criteria Residential Gym
I would not be to concerned about the impact loading. It is basically a question of creating a deformation zone or use the deformation in the slab itself.
You can find some info here: http://www.engineeringtoolbox.com/impact-force-d_1...
If you have 5-10 people jumping coordinated, that can be a problem. They can create forces up to 10 Hz depending on the loadmodel. What are the adjoining rooms used for?
In my experience the people that are jumping don't get disturbed by their own activity. But the neighbors who only feel the vibration and not the source can be very disturbed.
I have done calculations like that on several occations.
Regards
Thomas
RE: Vibration Design Criteria Residential Gym
nothing sacred about 4" - just seems like a good number. I found out the hard way about the post-installed anchor requirements!
RE: Vibration Design Criteria Residential Gym
RE: Vibration Design Criteria Residential Gym
Has a floor covering been specified? Low tech as they are, those mats that the commercial gyms use make a world of difference with respect to impact and sound.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Vibration Design Criteria Residential Gym
RE: Vibration Design Criteria Residential Gym
And the mat will also help with the vibrations from aerobics. But it is difficult to set a number for the effect. I tried a few years back with the help of a manufacturer. But we never really reached any conclusion.
In your case, how probable is it that there are several people jumping in the gym while there are "sensitive" people in the adjoining rooms?
You mentioned that the floor has natural frequency 7 Hz, that number tells you when it will vibrate. But you probably want to know how much it vibrates. In my experience the natural frequency can be used to determine how to analyze the floor. It you are below approximately 8 Hz there is a risk for resonant response so you need a dynamic method, like modal analysis. Above 8 Hz, a quasi-static method can suffice.
Regards
Thomas
RE: Vibration Design Criteria Residential Gym
I talked with SDI about this - there are some deck profiles that work well for the dynamic loading. If you have AISC 360-14, on page 16.1-361, the second deck profile down was the type they referenced as working well dynamic loads.
RE: Vibration Design Criteria Residential Gym
RE: Vibration Design Criteria Residential Gym
For that type of loading you need to use a specialised platform similar to that used in weightlifting competitions.
RE: Vibration Design Criteria Residential Gym