Monday, July 16, 2007

Re: Wood interior wall studs

That was my thought to - blocking takes a potentially minor failure (you see the studs buckling, and I have) and turns it catastrophic where the whole wall goes at once. This might be a good time to mention that the end of the blocking run should be restrained for 2-3% of the total axial loads in the studs to prevent the buckling. I'm a bit surprised that nobody called me on my 2x6 studs which, in a senior moment, I managed to overlook as _also_ having an L/d of 80 (since the "2" doesn't change). Thank you for everyone who didn't beat me up over that.

As for the 5psf - it's darned hard for a _properly_ operating HVAC to produce 5psf, even before any balancing occurs.  5 PSF, though a small pressure differential for pressure applications, is a 100lb force on a 2-6/6-8 door, requiring over 50lbs of force at the handle to open, or enough to knock a small adult down if opened with the pressure on the far side. Oh, and slam dancing is definitely in the Cd=2.0 range for walls, though we always overdesign floors and walls in frat houses so I haven't really considered it before (no, I have no idea how I've gotten involved with so many Frat renovations).
Jordan

Paul Ransom wrote:
From: "Jason Christensen" <jason.christensen@wcaeng.com>     
   
We usually call out mid-height blocking to be installed as the wall is erected, since it is usually the y-axis controlling, the blocking will drop your Le/d so the x-axis would control.     
 Two studs or a row of studs blocked together only enforce that they will buckle in unison at the critical axial load if it is uniformly applied to all studs. The bracing shear has to be resisted at the blocking elevation to get a truly braced behaviour.  Regards Paul