Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Seismic Design Hypothetical

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Scott,

I was going by Gail's scenarios in which you (an
engineer) are describing to a lay person what the
differences.  You are right if you go with the second
scenario, it would be hard to see the pitch on the
spirals if the building is toped out.

I'm in total agreement about the moment connections
too.  Practically all lay people, not to mention quite
a few engineers, would be hard put to tell if a moment
connection was designed to go plastic just by looking
at it.

You're not wrong about dampers and base-isolation, it
is rare, but it's a sure sign of seismic design.

I would have to scratch my head if I saw an EBF in a
low seismic area though.  I'm not thinking about brace
connection where the lines of force don't quite
intersect to in order to accommodate detailing.  Why
do an EBF if you aren?t trying to accommodate
movement?

My point, that I didn't see anyone else make before,
is that a major characteristic of seismic design is
that it needs to accommodate ductile movement.  And,
you can often tell if a structure was designed to
accommodate that or not.  Even if the code allows you
to treat them both as equivalent static lateral
forces, that is a large simplification (but not
over-simplification) and the actual forces are
sufficiently greater so as to cause movement which
requires ductile detailing.

> The real difference is in the detailing requirements
that must be done for seismic that usually is not done
(at least not to nearly the same level) for wind, due
to the need to achieve ductility.<
Bingo!

All that said, I'm glad to get a rise out of someone. 
At least I know my stuff makes it onto the list.

Regards,
MJ


******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********