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RE: supporting masonry

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I've had the same problem myself, though I haven't ended up with a W40 yet (did design a W36x650 once, but that's another story).  I believe the practice around the office here used to be to apply the L/600 and 0.3" to dead load and hold the LL deflection to L/360.  But ACI 531 now mandates total load.  I do recall reading something in the commentary that says you can loosen the deflection requirements if the masonry is reinforced, but I haven't had to resort to that yet.
 
Gary
 
Gary J. Ehrlich, P.E.
Meyer Consulting Engineers Corp.
451 Hungerford Drive #113
Rockville, MD  20850
(301) 738-5690 phone
(301) 738-5695 fax
www.mcecorp.com
-----Original Message-----
From: Andrew Kester [mailto:akester(--nospam--at)bbma.com]
Sent: Friday, October 22, 2004 10:33 AM
To: seaint(--nospam--at)seaint.org
Subject: supporting masonry

Randy,
Just had to deal with deflection in members supporting masonry on a project I am working on, and that discussion comes up from time to time with other engineers. I believe the L/600 to be a sound provision, but the 0.3" seems a little strict. To me, there should be a table for spans over 15ft or so, that gives you a little leeway. I have a two story building, and a floor girder that picks up a sizeable point load from a beam, then spans some 33ft and supports 20ft of brick. Using 0.3" I specified a W40x149. Now I admit, I was overjoyed and ran thru the office yelling "GOOOOOAAAAALLLLLLLLL!!!" with my shirt over me head ala World Cup Final goal, as I had never designed anything so massive, and it really fed my male structural ego. However, the GC will not share my joy, but it is better then getting a call in two years to go look at the cracks in that brick wall I designed and tell them what to do with the wet drywall.....
 
Bottom line is stick with code for now and hope they append to it. Better then explaining why you went with 0.7" to a lawyer.
 
Andrew Kester, PE
Longwood, FL