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RE: Quake study tests a home's strength

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David:

With the scenario you describe there will probably be less structural damage
because of the base isolation from the anchor bolts not being installed.

This house was supposedly only a couple of thousand square feet.  I hate to
side with NAHB in a gut feeling way but I feel pretty safe in 2000 square
foot houses [that have some walls] even when they weren't engineered. 

They had the Mentasta earthquake up here a few years back which was larger in
Magnitude than Northridge. Yes, it occurred in sparsely populated areas, but
these places had no or little building code enforcement and the houses did
not include seismic design considerations. Houses did pretty good
structurally speaking. Where there was structural damage it was from
buildings bouncing off the foundations.  

What scares me in earthquakes is the storage racks in Home Depot and Lowes.
I want to see some current tests on these racks and see how far they can
launch a pallet of 5 gallon buckets of paint or a refrigerator - also see if
some of the assumptions being used by designers are valid.

Respectfully,
Scott.

-----Original Message-----
From: David Merrick [mailto:MRKGP(--nospam--at)winfirst.com] 
Sent: Wednesday, November 15, 2006 8:34 AM
To: SEAINT
Subject: RE: Quake study tests a home's strength


Will it test real construction with the most common missing details?

Have a 2nd house be randomly picked from one of twenty, built in bad 
weather and with the low bidder.
Do not let builders and inspectors know that the house will be moved 
onto at test table and rattled around.
Compare results to the house made on the table.

The design engineer will want to reduce design complexity. The code 
writer and conference lecturer will add more demands. The plywood guy 
will fail the gyp boooooard shear wall. The prefab wall guy will out 
perform anything else. The sheet rock guy will demonstrate how truly 
with all of the design penalties, gyp board is better than plywood. etc. 
etc. etc.

I am now seeing prefabricated members and shear walls placed in very 
unstable ways, worse than conventional framing errors.

Like legos, at first there was a set of simple rectangular shapes. Now 
the multitude of details have left the children uninterested in the 
quality of what they make.

The true mystery of construction error should be handed over to the 
industrial psychologist.
I wonder what he would say about the affect of the changing industry and 
codes?

David Merrick, SECB, SE, CE

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