Quote:
Originally Posted by John_Vandercook
really? cause last time I checked, 500 cars weighs more than office chairs and desks.
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Quote:
Originally Posted by John_Vandercook
um, the garages are built to flex. They have to be very STRONG and have the flex in order to hold all those office chairs.
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You assume that the cars and the office equipment are both there 100% of the time. The building code does not.
Parking structure floors are built to 'flex' due to movement of heavy objects. Commercial and residential floors are built to be stiff for human comfort factors (less deflection and reverberation) and life safety (more dead loads...e.g. loads that are present 100% of the time).
The basic lbs. per SF of area for live load (loads that are not constant) for office and for garages are about the same. But since free-standing parking structures require longer spans (based on the parking layout and circulation), and the beams need to deflect greater due to greater movements, the live loads on the beams can be reduced by up to 40% since the beams serve a wider area. That same 40% reduction can also happen in residential and commercial space, but is likely to me much less (usually 10-15%) due to the fact that bay spacing in those buildings is nearly always significantly smaller.
So the floors in a parking structure are built to 'flex' and technically carry less load and the floors in a commercial or residential structure are built to be stiff with less deflection.
BTW, assembly areas (uhhh...nightclubs, restaurants, etc) allow NO reduction in the beam loading. A typical parking structure floor can't support that (or a storage use either) and is UNLIKELY to be able to support a residential or commercial use (though I have seen it done in an old parking structure in Boston's Back Bay which was converted to an apartment building).
Standard Live Loads (with no reductions) in lbs. per SF:
Assembly areas: 100-125 psf
Parking garages: 50 psf
Residential: 40 psf
Storage (light): 125 psf
Storage (heavy): 250 psf
Pedestrian bridges and walkways: 100 psf
FYI, the dead load (weight of the materials carried and permanent fixed features), the live load (non-constant load based on use), material and span are four of the main factors architects and engineers use to size beams.
My point is that it's unlikely that the existing garage can support either type of conversion (commercial or residential) above the first floor. Commercial would require too much vertical space anyway (typical floor to floor in a parking garage is 9'-6" which is WAY low for commercial space). Residential is a small possibility, but it would require some major reconfiguration of the vehicle circulation in order to keep the parking.
It would at least be an interesting study to do as a designer.