CHB or CMU has its own reinforcements. The reinforcements are two-way.
Horizontal bars are spanning and anchored to the columns and vertical bars
are anchored to the girders / beams. If a gap is provided between the
columns and the walls, the gap would only be minimized and not maintained
since the wall would sway together with the beams / girders and columns. And
if the wall would attach itself, it would not create additional stiffness to
the column and cause failure since only a part.
Here in the Philippines, we do not use CHB as part of the lateral force
resisting system. It is an unreliable method / system for lateral
resistance. The sad thing also is that the strength and durability of CHB
here cannot be trusted much more if it was bought in a local hardware. Maybe
if it's "Jackbilt" or "JackBuilt".
> From: Rodrigo Lema[SMTP:rlema(--nospam--at)arnet.com.ar]
> Reply To: seaint(--nospam--at)seaint.org
> Sent: Friday, June 18, 1999 1:17 AM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: Seismic - Isolating CMU infill wall
> I think Mr. Roselund is right. There is no such thing as an
> isolation of the so called "non-structural elements". If you put
> in the gap, it will attach the wall to the structure as soon as the EQ
> strikes and all your assumptions will be absolutely ignored by it
> EQ's don't read calcs, they have never been to school).
> And if you need the walls, why not use them as part of the
> lateral-resisting system? Of course you will need to take into account the
> possibility of removal (and with that in mind provide the reinforcement in
> the frames). To model this situation (infilled frame), refer to FEMA 310
> other threads discussed in this list not so long ago.
> Rodrigo Lema.