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RE: SEISMIC: Design in Pakistan; General Questions

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As pointed out, it depends on what you are building.  I would only get a site specific report if I was doing a base isolation project or other critical project requiring seismic qualifications of components.  A site-specific report with time-histories will run about $50,000 for Pakistan (upper end ROM).  There are a couple of firms that can do this and have done a lot for USAID work.  If you just need the Ss and S1, you can probably get that from USGS. 
 
About 10 years ago there was a project called GSHAP that was funded by the UN IDNDR.   http://www.seismo.ethz.ch/gshap/  The GSHAP information is in the process of being integrated by USGS to eventually provide world wide seismic hazards relative to lat/lon. 
 
Regardless of the code, you need to ask yourself, what is good engineering practice?  I would be inclined to use as good of information as possible for the Ss and S1 and use the ASCE 7-05.  There are very good engineering reasons that the UBC-97 was superseded regardless of any jurisdiction having authority. 
 
Studies have indicated that in the San Francisco area, using the UBC, the base shear could have been off by a factor of 12.  It is not a time for "the sky is falling".  The structural margins and requirements for nonlinear performance should provide collapse resistance.  But we should use the best tools available. 

Regards, Harold Sprague


 

From: sshahid(--nospam--at)engineering-solutions.biz
To: seaint(--nospam--at)seaint.org
Subject: RE: SEISMIC: Design in Pakistan; General Questions
Date: Tue, 23 Feb 2010 11:15:45 +0500

David,

Peshawar is 1500 km in the north of Karachi.

 

Bill,

In Pakistan UBC-97 rules for seismic and ACI318 for everything else (for buildings), the seismic zoning map of Pakistan specifies zones according to UBC. Karachi is Zone 2B, as we move eastwards it becomes Zone 2A (how many miles I am not sure).

Regarding 3 are you referring to a seismic hazard analysis for the site, deterministic or probabilistic? Is the structure of such importance that it warrants a specific study?

 

Hope this helps.

 

Best regards,

Shiraz Shahid.

 

From: David Topete [mailto:d.topete73(--nospam--at)gmail.com]
Sent: February 23, 2010 05:32
To: seaint(--nospam--at)seaint.org
Subject: Re: SEISMIC: Design in Pakistan; General Questions

 

From UFC 3-310-01, Structural Load Data...

 

                             MCE Ss   MCE S1 10/50 Ss  10/50 S1  

Pakistan Peshawar 105           42          53            21 

 

I don't know what help this may be...  Good Luck...

 

On Mon, Feb 22, 2010 at 2:09 PM, bill(--nospam--at)polhemus.cc <bill(--nospam--at)polhemus.cc> wrote:

I know we've got some engineering brethren here from the subcontinent, so please chime in if you would.

 

1. What are the seismic design criteria in Pakistan? (The area I'm looking at is about fifteen miles southeast of Karachi).

 

2. Would use of the NEHERP/ASCE 7/IBC provisions be well-received there?

 

3. If the answer to no. 2 is "yes," how would we go about conducting a site-specific study to establish the key seismic design parameters? I had thought that the relevant standards addressed that, but they seem to be limited to establishment of site classification, and only touch briefly on the actual spectral acceleration parameters (e.g. NEHRP 3.4). So, has anyone been involve in actually coming up with the site-specific spectral acceleration parameters?

 

Thanks, that'll do for a start. ;-)




--
David Topete, SE



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