Structural Engineering: RE: Unreinforced Adobe Brick in California? Really?

I’m a florida mutt, so my seismic understanding is poor at best… so my questions here are a) is the structure still standing? And b) Harold, do you have a resource where I can get a better understanding of what you mean by “linearly elastic” in this context and how something brittle can be considered elastic (aside from one brick sliding atop another, I guess)?

thanks

From: Harold Sprague [mailto:spraguehope@hotmail.com]
Sent: Thursday, June 18, 2009 12:21 AM
To: seaint@seaint.org
Subject: RE: Unreinforced Adobe Brick in California? Really?

We have had this discussion in code development many times. If you design a structure properly to remain linerarly elastic for a 2,500 year event, there should be nothing in the code preventing you from doing so. Even adobe can be designed to be linearly elastic. There are many unreinforced masonry structures that have been in service for thousands of years even in seismically active areas.

It has been quite a while since we have had an event that pushed the 2,500 year mean recurrance interval.

Regards, Harold Sprague

From: t.w.allen@cox.net
To: seaint@seaint.org
Subject: Unreinforced Adobe Brick in California? Really?
Date: Wed, 17 Jun 2009 14:36:45 -0700

I saw a set of plans today which depict a single family structure apparently constructed from adobe brick. The drawings indicate a full basement and the walls consisting of 4" H x 12" L x 16" W adobe brick. There is horizontal steel (2-#2) at "Every Four Courses", but no vertical steel. The date of the drawings is 1977 and they are signed by a S.E.

Is this possible? I mean, I know it's possible that I saw the drawings, but is it possible that this type of construction was permissible in the 1970's? The structure is located in a remote section of Riverside County, so code enforcement could have been "less than optimum".

I'm just wondering what I'm missing.

Thanks,

T. William (Bill) Allen, S.E.

ALLEN DESIGNS

Consulting Structural Engineers
V (949) 248-8588 • F(949) 209-2509

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