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Re: seaint Digest for 17 Jan 2002

[Subject Prev][Subject Next][Thread Prev][Thread Next] Mike:

One of the most important requirements at the reinforced concrete column design is in keeping the controlled tension within the limits that prevent concrete from loosing its bearing capacity. Until this requirement is met, an increase of axial load may be beneficial for the column itself and building in general. Unfortunately, it isn't the case we witness during  the demonstration at  http://peer.berkeley.edu/testing/kron_broadcast.mpg .

Valentin Shustov, P.E., Ph.D.
CSUN
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From: Michael Hemstad <mlhemstad(--nospam--at)yahoo.com>
Subject: Technical Aspect?
To: seaint(--nospam--at)seaint.org

I agree that it's unfortunate an apples-to-apples
comparison couldn't be made.  However, most of the
columns I've ever designed were in the
tension-controlled range, and would have been
strengthened by increased axial load.  Without knowing
the particulars, I'd hesitate to jump to any
conclusions about the test.

Mike Hemstad, P.E.
TKDA
St. Paul, Minnesota
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Subject: Technical Aspect? Date: Wed, 16 Jan 2002 13:56:52 -0800
From: "Dr. Valentin Shustov" <valentin.shustov(--nospam--at)csun.edu>
Organization: CSUN, College of ECS, Department of CME
To: seaint(--nospam--at)seaint.org

A thrilling video footage is available at
http://peer.berkeley.edu/testing/kron_broadcast.mpg. The project primary goal is to investigate the progressive collapse of a 6-7-story reinforced concrete frame building columns of "new" and "old" design during a shake table earthquake simulation. As a result of the reported testing, the new design of reinforced concrete columns "proved" to be
much better than the old one.

Unfortunately, the "old technology" square column in the middle of tested bent is loaded with the axial load (weight of the tributary surcharge) twice as much in comparison with the loads supported by any of the "new technology" circular columns on each side, which condemns the "old technology" to a premature failure and makes the conclusion
about superiority of the "new technology" questionable.

What do you think about it?

Valentin Shustov, P.E., Ph.D.
CSUN

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