Wood subfloor load capacity

[LesJr]

Being a mechanical engineer, I'm looking for help with wood subfloor loads and capacities. I have a 12' x 15' structure supported by 4 block walls with 2" x 10" joists. Each joist resides on the block walls, no need for joist hangers. The joists are 15' long on 16" centers. There is 1/2" standard plywood for the subfloor material. What is the load limit for this floor (SYP joists)? What is the load limit between the joists or how much will just the plywood hold? How much will each joist hold across this span and what is the distributed load maximum? I guess a maximum psi for each material will help solve the problem. I 'm looking to store heavy injection molds and don't want them to come crashing down. Each mold has a foot print of 12-15" by 12-15" and can way 500-2000 lbs. Plus, this will handle misc. storage needs.

Please advise, Les.

Les

 

[boo1]

The joists will limit the design loading. It is 50 psf live load, 20 psf dead load, 360 deflection for No 1 SYP or 40 psf live load, 10 psf dead load, 360 deflection for No2 SYP.

See:

http://www.southernpine.com/tables/index.htm

Table 6 Floor Joists, Assume you checked the bearing loading.

for the PSI capacity No. 1=1850, No. 2=1500psi
See:

http://web.usna.navy.mil/~greg/en442/files/NDS Tables.xls

 

[LesJr]

So, if I'm reading this right. At 20 psf dead load and a 12'x15' surface (no.1 syp 2x10's, 16" centers), my max is 3600 lbs (not taking concentrated loads in this number)? I was unable to access the psi link you have listed.

Thanks again,

Les

 

[boo1]

No, the dead loads, D are long-term stationary forces that include the self weight of the structure and the weight of any permanent equipment (joists, decking and shelfs).

Live Loads, L are short duration forces which change in location and magnitude. Based upon intended use of building = occupancy. Floor uniform loads are a function of use/occupancy.

for examples, the uniform floor load for:
residential = 40 psf
offices = 50 psf
light industrial storage = 125 psf

See Section 1606 of UBC for live load reductions.
See Section 1604.3, first paragraph, for area of load application.

The code specifies various combinations of loads (also known as load cases), that should be evaluated to determine which cases are critical to the structure. The '97 UBC combinations of loads are a significant change from previous editions with an emphasis given to strength design and a move toward ASCE 7 provisions. Load combinations for allowable stress design are specified in '97 UBC 1612.3.1. They are:

D
D + L + (Lr or S)
D + (W or E/1.4)
.9D ± E / 1.4
D + .75 [L + (Lr or S) + (W or E/1.4)]

I provided the bending stress values in the earlier post. See published values at:

http://www.southernpine.com/designvalues1.htm