Metal Bldg Drift w/ Brick Veneer
Metal Bldg Drift w/ Brick Veneer
(OP)
http://www.eng-tips.com/viewthread.cfm?qid=111916
http://www.eng-tips.com/viewthread.cfm?qid=86767
http://www.eng-tips.com/viewthread.cfm?qid=92878
We engineers truly cannot agree on a drift criteria. I’m looking at a metal building with brick veneer/metal stud back-up and would like to give the metal building mfg'r a drift requirement but cannot decide where to go on this one. Does anyone have a code reference that addresses this issue and not judgment, rule-of-thumb or past job experience?
TIA
http://www.eng-tips.com/viewthread.cfm?qid=86767
http://www.eng-tips.com/viewthread.cfm?qid=92878
We engineers truly cannot agree on a drift criteria. I’m looking at a metal building with brick veneer/metal stud back-up and would like to give the metal building mfg'r a drift requirement but cannot decide where to go on this one. Does anyone have a code reference that addresses this issue and not judgment, rule-of-thumb or past job experience?
TIA






RE: Metal Bldg Drift w/ Brick Veneer
RE: Metal Bldg Drift w/ Brick Veneer
RE: Metal Bldg Drift w/ Brick Veneer
There was an article in December 2004 by the MBNA in "The Construction Specifier" magazine "Specification and Design of A Metal Building System" that discussed both drift and deflection. For "non-reinforced masonry" they refer you to the AISC "Serviceability Design Considerations" design guide.
A few years age I did a metal building with non-load bearing cmu at the exterior walls. I reviewed the NCMA publication "Concrete Masonry Walls for Metal Buildings", which had suggested details for creating a hinge at the base of the walls. I decided that the details were not terribly practical, and ended up specifying max drift = L/150, with careful detailing.
RE: Metal Bldg Drift w/ Brick Veneer
If the issue is drift, and the backup studs will stay "straight", simply tilting with the drift, assuming a hinge at the bottom may be just fine. Then you get into the new eccentricity of the brick weight, bearing footprint, and mortar strength.
RE: Metal Bldg Drift w/ Brick Veneer
RE: Metal Bldg Drift w/ Brick Veneer
RE: Metal Bldg Drift w/ Brick Veneer
RE: Metal Bldg Drift w/ Brick Veneer
RE: Metal Bldg Drift w/ Brick Veneer
How do you address building drift then?
RE: Metal Bldg Drift w/ Brick Veneer
My post yesterday (see above) addresses drift. H/360 with 0.7 x Wind
RE: Metal Bldg Drift w/ Brick Veneer
RE: Metal Bldg Drift w/ Brick Veneer
360 is 50% higher (better) than the code minimum of l/240 for "deflection/drift" in IBC Table 1604.3.
However, it is only a number! I have not gotten any response back from the metal bldg. mfr yet.
RE: Metal Bldg Drift w/ Brick Veneer
RE: Metal Bldg Drift w/ Brick Veneer
UFC guideline is L/600.
http://www.wbdg.org/ccb/DOD/UFC/ufc_3_310_02a.pdf
RE: Metal Bldg Drift w/ Brick Veneer
H/240 as I have said before is an extremely stringent set of criteria to make a low rise building fall into. This is not stringent from the fact of design, but from cost....h/240 is a very serviceable number....h/300 is still possibly serviceable, but h/600 has huge cost implications all the way around...is it really worth this???
I am pointing these facts out not from the fact of a Pre-
Engineered Metal Building Manufacturer keeping things cheap....but from the point of a structural engineer trying to keep deflections reasonable, costs down, and variability between deflection calculations within tolerance....as all are!!!
RE: Metal Bldg Drift w/ Brick Veneer
Tax dollars at work (the UFC),
and
Anyone can build a brick...outhouse.