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]
For a typical parking structure:
 
During construction a casual observer may note the amount and size of reinforcing, close spaced ties, horizontal bars terminating in hooks for walls and so on.  Seismic design is distinct from wind, especially in high-seismic regions.  The post-elastic ductility / detailing requirements are where the real differences occur. 
 
Post-construction, the differences would be really only noticeable in the heavier walls, maybe with boundary elements, or the number of walls, or the size of beams and columns for frame systems.  For pre-cast there would be heavier topping slabs, but that would be hard to see.
 
Unless the person was actually versed in what a "non-seismic" parking structure looks like, the differences would probably never be noticed at all.
 
Maybe in wood frame construction the regional differences would be much more apparent to the casual observer during construction, but not in the finished product.  In completed commercial type development you really can't point to any basic elements and attributes and say "this is seismic, this is not".
 
If the issue is to describe what it is a structural engineer does, the fact that there is a building at all is the better example.
 
A good alternative visual aid for seismic design would be some of the hospital retrofits.  One in particular I have seen somewhere in the West Covina area (?) is an entire externally applied braced frame system, aesthetically placed to be a form of architecture rather than just a brute force fix.  Really a remarkable effort, with the finished project looking better than the original in my mind.  I don't know who did it, but they get a giant "well done" from me.
 
 
----- Original Message -----
Sent: Monday, August 29, 2005 9:37 AM
Subject: Seismic Design Hypothetical

Just to make it clear, I am not looking for specific answers for a specific situation.  It's just kind of a general question.  It has been said (often) that engineers don't get any respect because nobody knows what they do.  And maybe nobody knows what they do because they don't seem to be able to show people.
 
I don't do seismic design, so I don't have a good feeling for it.  Hence my question.
 
Admittedly, the situation posed is hypothetical, but most people are faced with dozens of hypotethical, what-if situations each day.  And manage to deal with them.
 
Say it was an "open" parking garage in DC.  Low seismic.  20 psf wind.  Gravity load would control.  How would the same parking garage in San Francisco look different?
 
Gail Kelley