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One more: bearing on cmu wall

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When bearing directly on masonry by some gravity element, I interpret the
code to require 0.25(f'm) max bearing in relation to immediate contacts
only.  However, when timber sole plates, caps, ledgers, steel CC supports,
etc, are present, I consider the capacity of the external member not f'm.
The CMU wall is a deep beam (Global) relative to the sole-plate/cap/ledger
above and is not subject to the 0.25(f'm) capacity (local) limit.
Consider the placement of joists over basements and purlins/rafters on cap
plates.  Can't do that at 0.25(f'm) unless the wall is considered for
global capacity.

Did I miss the point on this one?  I would appreciate other interpretations
or additional clarification of this issue.





Roger Turk <73527.1356(--nospam--at)compuserve.com>@compuserve.com> on 05/22/2000
04:38:57 PM

Please respond to seaint(--nospam--at)seaint.org

To:   seaint(--nospam--at)seaint.org
cc:
Subject:  RE: bearing on cmu wall


But wood bearing is based on an acceptable deformation (crushing) of the
wood
of 0.04".  (1991 NDS, Section 4.2.6.)  What would the allowable bearing on
masonry be *if* it could deform, without failing, 0.04"?

And, of course, ACI 530 has no provision for "Special Inspection."

Numbers are placed in our codes in wondrous ways!

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Tarek Mokhatr wrote:

>>And that value is assuming special inspection.

Tarek Mokhatr, SE



>Querry:  Std medium wt CMU @ f'm=1500 psi would provide only
0.25(1500)=375
>psi < DF#2.  Thats all?
>
>
>
>
>"Ken McClure" <kmcclure(--nospam--at)f-w.com> on 05/22/2000 06:56:56 AM<<