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RE: Masonry Expansion Joints

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You need to differentiate between expansion joints and control joints.  I
generally run the top bond beams through control joints.  

I had this conversation some time ago with some people at the NCMA.  The
issue gets more complicate when you consider out of plane loads.  

The general opinion is that you want to use a beam and column analogy for
gravity and out of plane loads and reinforce accordingly.  The joint should
occur as close as possible to the opening and the beams and columns should
be sized and reinforced appropriately.

If the masonry is cladding with a stud back-up, the out of plane load is
resisted by the studs.  The gravity load of the lintel (usually an angle)
should bear on about 8 inches of masonry.

Harold Sprague, P.E.
The Neenan Company
harold.sprague(--nospam--at)neenan.com


-----Original Message-----
From: BSmithSE(--nospam--at)aol.com [mailto:BSmithSE(--nospam--at)aol.com]
Sent: Tuesday, December 08, 1998 11:21 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Masonry Expansion Joints


The discussion of masonry reinforcing reminded me of expansion joint I saw
in
Mesa Arizona while visiting folks who retired there.  It was at a tract of
new
single family residences built with masonry exterior walls and wood roofs.
I
noticed that the vertical expansion joints were located at one end of
sliding
glass door openings.  The location made sense since this is at the weak link
of thermal contraction.  But how do lintels for the openings find bearing
with
the expansion joint at the end?  

Perhaps the expansion joints I saw aren't true expansion joints and that all
the horizontal reinforcing continues through?

In my practice, vertical expansion joints are indicated on masonry wall
elevations (I use 2x wall height as the maximum spacing as Jim Amhrein once
recommended).  However, when there are numerous door and window openings,
locating the expansion joint between the openings seem futile.  I should
like
to locate the expansion joint at the edge of an opening.  

Any thought?

Brad Smith