jdgengineer
Structural
- Dec 1, 2011
- 748
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!
