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Re: Seismic - Isolating CMU infill wall

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Niaz A. Nazir wrote:

> If you have significant amount of infill on the perimeter, you might
> want
> to include them in you lateral load resisting system.  The detailing
> for
> nominally reinforced infill panels is much more reliable than if you
> wanted
> to isolate the panels.
>
> As far as increasing the shear demand in columns, by adding infill
> panel,
> the columns may demonstrate shear critical (short captive column)
> behavior.
> However, these columns can easily be designed to be flexure critical
> by
> providing sufficient confinement.  This concern is a valid one for
> existing
> (early 1900's) building where the columns are nominally reinforced for
>
> shear.
>
> The advantages that you get by integrating the infill panels into the
> lateral load resisting system easily out-weigh the disadvantages.  The
>
> advantages may include; smaller and lightly reinforced beams and
> column
> frames, lower drifts etc.

The experimental research we have conducted on concrete frames with
infill confirms Naiz's comments & concerns especially:

>> by adding infill panel,
the columns may demonstrate shear critical (short captive column)
behavior.
However, these columns can easily be designed to be flexure critical by
providing sufficient confinement. <<<<<<


--
Robert Kazanjy, PE  **Disclaimer: I speak for myself not UC-Irvine**
Senior Development Engineer
Civil & Environmental Engineering
UC Irvine
rkazanjy(--nospam--at)uci.edu