[CEUS-earthquake-hazards] (no subject)

[Joe Tomasello]

Zhenming:

 

My Chinese is not as good as my English so I'm in real big trouble with your
map. However, from the photos viewed on the internet my conclusions were
somewhat different; construction techniques appeared to play a large role in
the disaster and the high death toll. 

 

The pictures seem to indicate a large number of unreinforced (or
under-reinforced) mid-rise buildings as well as unreinforced masonry or
stone buildings.  While it may be customary in the region, this is an
ineffective type of construction because of the brittle behavior exhibited
when ground motion is introduced.  In addition, several pictures indicate
that some buildings simply overturned and fell on adjoining buildings.
These collapse patterns seem to be indicative of having soft stories lacking
in ductility (tall, brittle, un-braced concrete columns on the ground
floor). After the rescue effort is over I think researchers will find that
the signature of the ground motion frequency played a big part in which
building collapsed and which didn't. As you might recall a similar
phenomenon was observed in Mexico City where only 10 to 14 story concrete
buildings had catastrophic failures - and less ductile shorter or taller
buildings seemed unaffected.

 

Our prayers are with Chinese people in their dark hour.  

 

 

Joseph Tomasello, PE

5880 Ridge Bend Rd.

Memphis, TN 38120

 

Phone:

(901) 761-2016 office

(901) 821-4968 direct

(901) 412-8217 mobile

From: ceus-earthquake-hazards-bounces at geohazards.usgs.gov
[mailto:ceus-earthquake-hazards-bounces at geohazards.usgs.gov] On Behalf Of
David Overhoff
Sent: Friday, May 16, 2008 10:14 AM
To: Central and Eastern U.S. Earthquake Hazards Listserve
Subject: Re: [CEUS-earthquake-hazards] (no subject)

 

Thanks Zhenming.  I hope any family you might have in the region are safe. 

One thing we've noticed around here is that in all the photos and film seen,
there is no reinforcing steel protruding from the collapsed concrete. 
One photo we saw (Section A, page 8, USA Today, May 14th) showed large,
nearly regular-shaped slabs of what appeared to be concrete...the edges all
looked smooth and straight, as if they might have been pre-cast blocks
assembled on-site. 



David L. Overhoff, RG
Missouri Department of Natural Resources
Geological Survey Program - Geologic Resources Section 
Phone: 573.368.2182
david.overhoff at dnr.mo.gov





"Wang, Zhenming" <zmwang at email.uky.edu> 
Sent by: ceus-earthquake-hazards-bounces at geohazards.usgs.gov 

05/16/2008 09:18 AM 


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[CEUS-earthquake-hazards] (no subject)

 

		



I would like to share with you all the Chinese National seismic design map
(PGA with 10% PE in 50 years). This may explain one of the reasons that so
many schools and hospitals collapsed in the Wenchuan earthquake. 
  
Thanks. 
  
___________________________________ 
Zhenming Wang, PhD, PE 
Head, Geologic Hazards Section 
Kentucky Geological Survey 
228 Mining and Mineral Resources Building 
University of Kentucky 
Lexington, Kentucky 40506 
Phone:(859)257-5500x142 
Email:  <mailto:zmwang at uky.edu> zmwang at uky.edu 
Website:  <http://www.uky.edu/KGS/geologichazards>
www.uky.edu/KGS/geologichazards 
____________________________________ 
 [attachment "China-PGAmap.jpg" deleted by David Overhoff/DGLS/MODNR]
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