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Re: Alquist Priolo Occupancy

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Paul,
 
I would talk to the architect...
 
First, I would say that the routinely reoccurring mechanical and subsequent water damage to the walls, slabs, etc. is a certainty that is as litigiously potent as the collapse during a design earthquake (which we all pray never happens, http://www.livescience.com/forcesofnature/050622_new_madrid.html)
 
Second, I would bring the infamous pictures of the fences and roads slipping 15-to-20 feet across the fault lines.  No structure is realistically able to withstand such movement.   
 
Third, I would argue that the fault trace is something that cannot be accurately defined.  This means that any structure on the site in the proximity to the fault trace can be affected by the long- or short-term consequences of the slip.
 
Fourth, I would quote Peter Yanev (at least according to the Charles Richter's preface to his book, this gentlemen knew what he was writing):
 
"If you are thinking of purchasing property or a building within an active fault line, don't.<..> If you already own [such property], there are only three sad and costly alternatives:
 
a) relocate the building to a safer place;
b) abandon the building <...>; and
c) hire an engineer to advise you <...>.  Then try to secure an insurance policy for earthquake damage and hope for the best<...>    
 
It is very unlikely, however, that such measures could protect the building itself from expensive damage."    
 
Finally, I would say that designing and building any permanent structure intended for whatever human occupancy may not be quite responsible from the professional standpoint.  Splitting hairs over the code requirements is exactly that - hairsplitting.  Therefore, I would respectfully decline to participate in the project.
 
Steve Gordin, PhD, SE,
Irvine CA
 
 
 
 
 
 
 
 
----- Original Message -----
Sent: Wednesday, June 22, 2005 2:51 PM
Subject: Alquist Priolo Occupancy

We have a current project where the entitlement package is indicating the ramp to underground parking (covered as part of exterior courtyard) is crossing a designated Alquist Priolo fault trace.
 
My interpretation would be this is not permitted.  The Architects interpretation is that it is permitted as this is not an occupied structure (2000 hours per year).  I question this as, apart from the obvious problems of the retaining walls and ramp plus covering slab suffering differential movement crossing the fault trace, the courtyard is elevated and it is hard to quantify the occupancy.  The ramp is a means of egress with constant daily vehicle use, but also hard to quantify occupancy.
 
Any input from my peers?  Am I reading too much into this?  I know pools and hardscape are permitted to cross the fault trace, but they do not typically form a collapse mechanism.