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Collapse of Delhi IGI airport terminal roof in 21-8-09 storm
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ahujavipul
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PostPosted: Sat Aug 22, 2009 3:43 am    Post subject: Collapse of Delhi IGI airport terminal roof in 21-8-09 storm Reply with quote

I am wondering if any one has pictures of the roof collapse at terminal 1D. Delhi International Airport Ltd. (DIAL) has summoned the design architect to look into this.

A reporter asked DIAL why older buildings survived & not the new one. DIAL's reply was that its because its much taller and therefore more exposed to elements--the reporter thought it was a bizarre explanation! (Ref today's HT)

Regards

Vipul Ahuja
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kunalkansara
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PostPosted: Sat Aug 22, 2009 9:11 am    Post subject: Reply with quote

Please see the following newsclip:

http://www.youtube.com/watch?v=NLOHhvHj3ks

many thanks,

Kunal Kansara
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ahujavipul
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PostPosted: Sat Aug 22, 2009 10:21 am    Post subject: Collapse of Delhi IGI airport terminal roof in 21-8-09 storm Reply with quote

Thanks, Dr. Kansara,

From the pictures, it appears the structure is intact, though the cladding tore away. However they are not very clear in detail as to how the cladding was fastened to the structure--of course one would usually expect to see it on the drawing. I wonder if any one can shed light on this.

I find many designers do not design for greater wind effects in special areas--such as near edges & corners. Further special roof profiles are not covered in the code & require wind tunnel analysis. This helps the designer identify special situations for that profile among other design data.

Also usually this connection between cladding & structure is not engineered as it is a "proprietary" item. Of course one can't discount poor workmanship as a probable cause in this case.

Regards

Vipul Ahuja


kunalkansara wrote:
Please see the following newsclip:

http://www.youtube.com/watch?v=NLOHhvHj3ks

many thanks,

Kunal Kansara
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amarjeetsingh
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PostPosted: Sat Aug 22, 2009 1:58 pm    Post subject: Collapse of Delhi IGI airport terminal roof in 21-8-09 stor Reply with quote

Dear all,
 
this has become a common problem of sheets flying off in the wind. the connection between the sheets and the purlin is the place to make saving as majority of the people are looking at the foolprrof connections. these are left at the discretion of the sheet suppliers only and they cut the corners.  with a new type /profile of the sheet coming in market , majority of  sheeting vendors have strong marketing teams but very weak technical support teams.
I agree with Mr. Ahuja that of course poor workmanship is a probable cause in this case.
 
regrds
 
amarjeet singh


 
On 8/22/09, kunalkansara <forum@sefindia.org (forum@sefindia.org)> wrote:
Quote:
  Please see the following newsclip:



http://youtube.com/watch?v=NLOHhvHj3ks

many thanks,

Kunal Kansara







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sdec.in
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PostPosted: Mon Aug 24, 2009 11:10 am    Post subject: Collapse of Delhi IGI airport terminal roof in 21-8-09 storm Reply with quote

Hi Vipul
What you've written is absolutely true; but there is a provision in IS-800 of enhancement in permissible stresses not being applicable if Wind happens to be the dominant load for that type of structure, which happens to be the case here as well; some of the structures that I have reviewed had not being designed accordingly and the design had to be modified later.
It is really important to know what really went wrong here.

Regards
Sangeeta Wij
Quote:
----- Original Message -----
From: ahujavipul (forum@sefindia.org)
To: general@sefindia.org (general@sefindia.org)
Sent: 22 August, 2009 3:51 PM
Subject: [SEFI] Re: Collapse of Delhi IGI airport terminal roof in 21-8-09 storm


Thanks, Dr. Kansara,

Quote:
From the pictures, it appears the structure is intact, though the facade tore away. However they are not very clear in detail as to how the facade was fastened to the structure--of course one would usually expect to see it on the drawing. I wonder if any one can shed light on this.

I find many designers do not design for greater wind effects in special areas--such as near edges & corners. Further special roof profiles are not covered in the code & require wind tunnel analysis. This helps the designer identify special situations for that profile among other design data. Of course on can't discount poor workmanship as a probable cause in this case.

Regards

Vipul Ahuja


kunalkansara wrote:  Please see the following newsclip:



http://youtube.com/watch?v=NLOHhvHj3ks

many thanks,

Kunal Kansara






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ahujavipul
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PostPosted: Mon Aug 24, 2009 6:22 pm    Post subject: Re: Collapse of Delhi IGI airport terminal roof in 21-8-09 s Reply with quote

Dear Sangeeta,

I agree with you. I have initiated this discussion with the hope that some facts come to light about the incidence. I have not disputed the 1/3 rd increase not allowed by the code. But having said that, I don't ever believe that collapses in buildings occur due to a 33% error in estimation of loads (or incorrectly increasing allowable stresses). Rather gross oversights of connection (cladding to structure) details/design or poor workmanship could be the culprit.

Like you I'm also waiting for someone to throw more light on the situation or the matter will be blown away with the wind!

Regards

Vipul Ahuja

sdec.in wrote:
Hi Vipul
What you've written is absolutely true; but there is a provision in IS-800 of enhancement in permissible stresses not being applicable if Wind happens to be the dominant load for that type of structure, which happens to be the case here as well; some of the structures that I have reviewed had not being designed accordingly and the design had to be modified later.
It is really important to know what really went wrong here.

Regards
Sangeeta Wij
Quote:
----- Original Message -----
From: ahujavipul (forum@sefindia.org)
To: general@sefindia.org (general@sefindia.org)
Sent: 22 August, 2009 3:51 PM
Subject: [SEFI] Re: Collapse of Delhi IGI airport terminal roof in 21-8-09 storm


Thanks, Dr. Kansara,

Quote:
From the pictures, it appears the structure is intact, though the facade tore away. However they are not very clear in detail as to how the facade was fastened to the structure--of course one would usually expect to see it on the drawing. I wonder if any one can shed light on this.

I find many designers do not design for greater wind effects in special areas--such as near edges & corners. Further special roof profiles are not covered in the code & require wind tunnel analysis. This helps the designer identify special situations for that profile among other design data. Of course on can't discount poor workmanship as a probable cause in this case.

Regards

Vipul Ahuja


kunalkansara wrote:  Please see the following newsclip:



http://youtube.com/watch?v=NLOHhvHj3ks

many thanks,

Kunal Kansara






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varmap
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PostPosted: Tue Aug 25, 2009 8:00 am    Post subject: Reply with quote

I also have doubts on the wind loads being considered for design....local coefficients at corners & special shaped roofs are ignored.... In fact in one of the project i dealt with, local wind load came out to 500kg/sqm after a wind tunnel study!
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ajitkbhattacharyya
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PostPosted: Tue Aug 25, 2009 2:26 pm    Post subject: Collapse of Delhi IGI airport terminal roof in 21-8-09 storm Reply with quote

The efficacy of good fixtures under strong wind storm loads which occurs on unusual occasions must be tested and.a good designer should provide fail safe arrangement.The workers at site seem to be not trained for such open air structures.Lot of importance is now given to fixture spacing/withholding power.after experiencing many failures of this type.Does not speakwell of the expertise of the organisation doing the work,

With kind regards



A.K.BHATTACHARYYA

F.I.StructE (UK), FIE (India), FIBE, FIRT
H-2A, Hauzkhas, New Delhi -16, Ph:011-26854127

--- On Mon, 8/24/09, sdec.in <forum@sefindia.org> wrote:
[quote]
From: sdec.in <forum@sefindia.org>
Subject: [SEFI] Re: Collapse of Delhi IGI airport terminal roof in 21-8-09 storm
To: general@sefindia.org
Date: Monday, August 24, 2009, 5:28 PM

Hi Vipul
What you've written is absolutely true; but there is a provision in IS-800 of enhancement in permissible stresses not being applicable if Wind happens to be the dominant load for that type of structure, which happens to be the case here as well; some of the structures that I have reviewed had not being designed accordingly and the design had to be modified later.
It is really important to know what really went wrong here.

Regards
Sangeeta Wij
--auto removed--

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amarjeetsingh
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PostPosted: Wed Aug 26, 2009 8:32 am    Post subject: Collapse of Delhi IGI airport terminal roof in 21-8-09 stor Reply with quote

In today newspaper in Newdelhi GMR has come out with the list of architects/contractors for this airport job and the sheeting job has been done by one of the leading manufacturers. It seems to be a problem of combination of workmanship and the usage of incorrect coeeficient for design of sheetings/connections. All the sheeting work which has been done in the last 2 years is facing the same problem in  storms be it hardwar/rudrapur/manesor etc.These people were overloaded with work in the last 2-3 years and with huge turnover of people continuity became a problem even in the design offices also.
 
the water proofing contractor gives 10 years gurantee why cannot we tie the down the sheeting contractors for bad workmanship by holding some amount of the cost of works for say atleast 2 years.
 
regrds
 
amarjeet singh


On Tue, Aug 25, 2009 at 1:30 PM, varmap <forum@sefindia.org (forum@sefindia.org)> wrote:
Quote:
  I also have doubts on the wind loads being considered for design....local coefficients at corners & special shaped roofs are ignored.... In fact in one of the project i dealt with, local wind load came out to 500kg/sqm after a wind tunnel study!







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ibarua
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PostPosted: Wed Aug 26, 2009 11:06 am    Post subject: Collapse of Delhi IGI airport terminal roof in 21-8-09 storm Reply with quote

26th August 2009

Roof sheets are torn away from the purlins because the holes in the sheets are sometimes punched and not drilled (as they should be). Punching results in larger, irregular shaped holes that help the nut and washer on the J-hook to slip through. Also, in many cases, wind ties in the form of a MS flat 25*5 mm are not provided across the end rows of bolts or at the eaves.

Indrajit Barua.

On Mon, 24 Aug 2009 sdec.in wrote :
Quote:
Hi Vipul
What you've written is absolutely true; but there is a
provision in IS-800 of enhancement in permissible
stresses not being applicable if Wind happens to be the
dominant load for that type of structure, which happens
to be the case here as well; some of the structures
that I have reviewed had not being designed accordingly
and the design had to be modified later.
It is really important to know what really went wrong
here.

Regards
Sangeeta Wij

Quote:
----- Original Message -----
From: ahujavipul (forum@sefindia.org)
To: general@sefindia.org (general@sefindia.org)
Sent: 22 August, 2009 3:51 PM
Subject: [SEFI] Re: Collapse of Delhi IGI airport
terminal roof in 21-8-09 storm
Quote:


Thanks, Dr. Kansara,


Quote:
From the pictures, it appears the structure is
intact, though the facade tore away. However they are
not very clear in detail as to how the facade was
fastened to the structure--of course one would usually
expect to see it on the drawing. I wonder if any one
can shed light on this.
Quote:

I find many designers do not design for greater wind
effects in special areas--such as near edges & corners.
Further special roof profiles are not covered in the
code & require wind tunnel analysis. This helps the
designer identify special situations for that profile
among other design data. Of course on can't discount
poor workmanship as a probable cause in this case.
Quote:

Regards

Vipul Ahuja


kunalkansara wrote:  Please see the following
newsclip:
Quote:



http://youtube.com/watch?v=NLOHhvHj3ks
(http://youtube.com/watch?v=NLOHhvHj3ks)
Quote:

many thanks,

Kunal Kansara








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