The bolt head question has more than one possible answer. If you test using a bolt head in order to find the amount of weight per bolt head on your specific neoprene, then you have a constant to use when figuring your suspension, which should (new info here) run between 20% and maybe 60% deflection static, with all gear in the studio. This will allow for people, etc, to be added without exceeding about 80%, which would be getting close to the end of useful spring action with the neoprene.
If your tests show (I've NOT done this yet, so don't know ranges) that a bolt head is too small a surface, you can get thick 5/8" ID washers and tack weld them onto the heads of the bolts to spread out the contact area. This would give over 4 times the surface area and improve stability. Remember than in NO CASE can you CONTAIN the edges of your neoprene pucks, or their hardness goes through the roof...
40/20 loading refers to live/dead load for structures - you might actually want to go up to 60/20 ratings, which for 2x4's on 24" centers, assuming #2 and better fir, would be at 4' 5" maximum. You can get the rest of the methods of figuring this out on the "sticky" floating floor thread - it will entail a bit of "mad science", but at least you'll know where you stand (yeah, that was intentional, what can I say, I'm evil
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As far as material weights, framing lumber can weigh up to double, maybe more, depending on moisture content. Don't believe me? Go to Home Depot and sort thru their 2x4's, you won't need a scale to know how large a difference there is. Steel studs - negligible compared to all the drywall and other stuff.
For the rest, Here's the gist of a document I keep adding to on my desktop -
Weight of Standard Drywall panels -
Regular Drywall Panels.
Panel Size /Weight /Lbs/SqFt /PCF /kG/M^3
4' x 8' x 3/8" = /45 lbs. /1.406 /42 /675
4' x 10' x 3/8" = /56 lbs. /1.406 /42 /675
4' x 12' x 3/8" = /67 lbs. /1.406 /42 /675
4' x 8' x 1/2" = /54 lbs. /1.6875 /42 /675
4' x 10' x 1/2" = /68 lbs. /1.6875 /42 /675
4' x 12' x 1/2" = /82 lbs. /1.6875 /42 /675
4' x 8' x 5/8" = /74 lbs. /2.3125 /42 /675
4' x 10' x 5/8" = /92 lbs. /2.3125 /42 /675
4' x 12' x 5/8" = /110 lbs. /2.3125 /42 /675
Firecode Core Panels
4' x 8' x 5/8" = /70 lbs. /2.1875 /39.73 /638.5
4' x 10' x 5/8" = /88 lbs. /2.1875 /39.73 /638.5
4' x 12' x 5/8" = /105 lbs. /2.1875 /39.73 /638.5
To convert lb/cu ft into kG/m^3, multiply by 16.04. To convert the other way, divide by 16.04.
Concrete weights approx. 3600 lbs/cu yd when cured, about 3900 pounds wet.
133 lbs/cu ft, or 2133 kG/M^3 -
MDF - approx. 68 pounds per ½” 4x8 sheet
Glass = approx. 3 times weight per unit thickness of sheet rock - roughly 135 lbs for 4x8 sheet of 3/8” glass.
The surface density of ¼” plywood is 0.74 lb/sq ft, or 23.68 pounds per 4’x8’ sheet.
The surface density of ½” plywood is 1.48 lb/sq ft, or 47.36 pounds per 4’x8’ sheet.
The surface density of ¾” plywood is 2.22 lb/sq ft, or 71.04 pounds per 4’x8’ sheet.
I know this comes out crappy in BBS coding, I may post a PDF of it later with some other useful stuff, in another "sticky"... Steve
That's a great idea. One question, is there enough surface area on the bolt head not to cause problems? O.K. I lied, more questions 40/20 loading? I started adding all the weight of the sheetrock in the drum room yikes! I'll probably have some questions to make sure my calculations are correct. Any links for material weights 2x4's, plywood, steel studs etc. ?