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RE: Seismic - Isolating CMU infill wall

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Way to go man!

A. Yango

> ----------
> From: 	ASQUILALA(--nospam--at)[SMTP:ASQUILALA(--nospam--at)]
> Reply To: 	seaint(--nospam--at)
> Sent: 	Tuesday, June 22, 1999 2:21 PM
> To: 	seaint(--nospam--at)
> Subject: 	Re: Seismic - Isolating CMU infill wall
> To Rodrigo Lema:
> Answer the following questions:
> 	1.  	If you provide a gap which is a little bit more than the 
> anticipated deflection of the frame do you think the frame will still lean
> on 
> the wall?
> 	2. 	Assuming that the frame will lean on the wall but the wall 
> was not designed to resist the shear or lateral load, what will happen to
> the 
> wall?
> 		My guess is, it will fail ( or crack).
> 	3. 	If the wall will fail, will the frame be able to resist the 
> lateral load that has designed for in the first place?
> 	4.	Since you can't rely on the strength of the infilled wall
> how 
> can you use it for design?
> 	Manufacturers of CMUs have controlled environment to make sure that 
> their products are manufactured as per the specified strength.  They do
> test 
> their products using standard practice of testing.  This way they are sure
> that the strength of CMU in each specified design mix is attainable.  CHBs
> are not.  They are mixed at the site with some kind of proportion and
> without 
> the benefit of testing.  For all I know, CHB's strength is only about 200
> psi 
> (I'm not sure on this).  If your clay brick is the same as CHB in
> reliability 
> then it is hard to use the infilled walls to resist lateral loads without
> the 
> support of standard testing.  I know where you were coming from when
> thought 
> how these infilled walls can resist the lateral loads. But until somebody
> can 
> come up with a more established and controlled environment in producing
> the 
> CHBs or brick walls for that matter then using them for resisting the
> lateral 
> loads is not advisable.  Use CMUs or Jack-Built instead. (Jack Built is a 
> brand name of CMU).
> Alfonso S. Quilala Jr., P.E.