dimentional lumber resources

huangyhg

dimentional lumber resources
during a conversation reguarding the benefits of 2x6 vs 2x4 stud wall framing a question was possed reguarding the load capacity for the respective framing pieces.
does anyone know of any good resources, on the web or otherwise, that have specific load capacities of typical dimentional lumber and stud wall framing.
a figure of 625 psi was suggested for maximum compresional capacity of stud grad spruce.  any idea if this is accurate?
what would be a typical figure used for design calculations?
thanks.
mike (electrical)
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take a look at the american wood council website for good online technical information and links to more specific sites:
mike - to properly design a load bearing stud wall (exterior) you need the following:
1.  stud wall length
2.  nature of sheathing on both sides (braced condition)
3.  location of wall to determine necessary wind load speed.
4.  wind exposure category.
5.  applicable building code
6.  stud spacing
7.  stud wood species and grade - to get the allowable axial and bending stresses.
8.  axial load on the stud (dead, floor live, roof live, snow, etc)
9.  proper combinations of the loads
10.  a check of the stud based on combined bending and axial loads.
with the ibc residential code (and with most model building codes) - you can look up studs in their tables that condense the above items, but you do need to know what wind zone you are in and the species/grade to get the stud checked properly.
jae, i appreciate your reply.  some of the information that you have provided is enlightening, however, the essence of our discussion was more an exercise in academics.  the intent was not to design a stud wall, but to quantify the difference between a similarly framed stud wall with 2x4 vs. 2x6.  also, the question was posed about the specific compressive strength of a given piece of lumber.  i recall seeing a video of a destructive compression test on a 2x4 stud.  i was hoping to quantify a typical failure pressure for such a piece of lumber.  
i see now that it might not be a simple mater of putting a figure on it, as many factors contribute to strength of a given wall or piece of lumber.
the awc site proved to offer little relevent information, however, it had other interesting information.
thanks.
mike
disclaimer..... please don't use this for design it is only a guidline and depends on many things..... but for academic purposes
1 2x6 doug fir stud in a 9' interior wall with normal floor loading is worth approx. 7400 lb
1 2x4 doug fir stud in a 9' interior wall with normal floor loading is worth approx. 2800 lb
assuming you are referring to exterior residential stud wall application.  there are three areas to consider in the wall performance: 1 structural response 2 thermal performance 3 moisture control.
the studs are sized interactively sized using: bending load, critical column buckling, and interaction equation to check   
boo1, you might want to check your calculations regarding the allowable height with a 2x4.  based on my experience, exterior wall constructed with 2x4 dfl "stud" grade spaced at 16" on center are actually overstessed by a few percent on a normal 8 feet wall.  this is using combined loading, vertical floor loads + lateral (components and cladding) wind loads.
in my opinion, any wall over 8 feet should be 2x6.
florida's current code bodies allow it see:
the ads manual for engineered wood construction structural lumber supplement table 5.2a and 5.2b gives axial compression allowables for 2x4 and 2x6 lumber of various grades and various lengths.  the table assumes that the studs are braced along the 2" nominal width and the limiting buckling is the 4" and 6" nominal width.  table 5.2a is for duration 1.0 and 5.2b is for duration 1.15 (snow).  for no. 2 spruce-pine-fir the allowable load in pounds are
length   2x4   2.6
8 ft    3000  8710
10 ft   2010  6700
as far as the framing controversy on 2x4 vs 2x6 studs the 2000 irc table r602.3.1 shows the prescriptive allowable length of wood stud walls based on the number of floors supported.  in essence it says that a 10 ft tall 2x4 stud wall 16" o.c. can support a floor and a roof for their "model" structure.  2x6 walls 24" o.c. can be prescriptive up to 14 ft without engineering.
rockengineer,
your examples from the ads manual seem to relate only to axial loads.  
csellc,
your comments talk about combined axial and bending (wind loading).  
could you both clarify this?  it seems that two different loading schemes are being discussed.
exterior wall studs should be designed to resist both vertical (live loads, dead loads, snow loads, etc....) and horizontal (lateral) loads, such as wind.  in theory, there is no difference in the design of exterior wood wall studs or light gage metal studs for example. (let's neglect the difference in design properties or materials, etc....) you still need to design the studs for all the loads.  
based on this, if you analyze a standard exterior 2x4, 8 feet (92-5/8" precut studs with double top plate and sole plate) high wall df-l stud, spaced at 16" on center, in a "standard two story center hall colonial type residence, you will find that the exterior wall studs are overstressed about 5%.  this assumes 40 psf ll, 15 psf, dl, and 30 psf snow and 80 mph, exposure b  "components and cladding" wind pressures.
rockengineer,
about 15 years ago, i did a loading chart of built up 2x4 and 2x6 posts as well as solid 4x4, 4x6, and 6x6 posts, ranging in height from 8 feet to about 22 feet.  based on my charts (or what is left of them), the allowable axial loads you listed for spf are about the same i determined using df-l.