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RE: Concrete Masonry Load Bearing Buildings

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Randy,

- Cost, steel Vs masonry?
The masonry does double duty.  It is the skin and it carries the loads.  In
most markets it is difficult to beat.  The thermal aspects warrant
consideration.  The brick with block back up and polystyrene insulation in
the cavity work best.  The interior wall is painted, and you have a very
durable wall system that is supporting the gravity loads.

- Resistance to seismic and wind loads?
Very good even in tornadic loads.    Very good in high seismic.  Use solid
grouting for high seismic and tornadic wind resistance (ETPA's).

- Quality control of construction?
Require special inspection.  Look to the UBC for special inspection
requirements.  Special inspection is an inferred requirement of BOCA.

- Anything to look out for?
Use "A" block (fewer rebar splices, easier to grout).  Start the bottom and
finish out the top with 2 course bond beams.  Look at the Corps of Engrs.
web site for good details
http://cadlib.wes.army.mil/cgi-shl/dbml.exe?action=Query&template=secure.dbm
.  Look at the UBC details in the back of Volume 2 for good reinforcing
details. 
Watch testing.  Do prism tests for f'm over 1500 psi.  Prisms are the most
desirable, but you can get by with component tests.  

- etc etc
Talk to the local masons, and find out what is customary.  In some markets
masonry can increase in cost by a factor of 4.
Get:
	1.  Reinforced Masonry Design by Schneider & Dickey
	2.  Reinforced Masonry Engineering Handbook by Amrhein
	3.  A Manual of Concrete Masonry (NCMA Tek Notes)
	4.  199 Masonry Standards Joint Committee Code, Specification and
Commentaries.
	5.  Masonry Structural Design for Buildings, Army TM 5-809-3
	6.  USACE Masonry Details, Standard Detail No. 000-90-04
	7.  Mortar Net product literature.
Talk to the local block and brick suppliers get a copy of their standard
shapes.  Properly specify grout (Re: Schneider & Dickey).
Get a peer review at all of the stages of your first project.

Regards,
Harold Sprague
The Neenan Company


-----Original Message-----
From: Randy Diviney [mailto:rsdiviney(--nospam--at)hayeslarge.com]
Sent: Thursday, October 07, 1999 8:05 AM
To: seaint(--nospam--at)seaint.org
Subject: Concrete Masonry Load Bearing Buildings


I am a structural engineer employed by an architectural firm. We do mostly
education (80%) and medical facilities (20%). Recently the partners of my
firm requested we do schools as masonry load bearing rather than steel
frame due to costs. Our projects are all in the north east and usually 1 to
3 stories. I don't really care for the load bearing system. Perhaps it's
because I am so accustomed to doing steel frame. It seems I can handle
lateral loads and changing roof and floor elevations better with steel.

Does anyone have any thoughts on masonry load bearing vs steel?

- Cost, steel vs masonry?

- Resistance to seismic and wind loads?

- Quality control of construction?

- Anything to look out for?

- etc etc

Randy Diviney
Structural Engineering Dept.
Hayes Large Architects
Altoona, Pa