www.sefindia.org

STRUCTURAL ENGINEERING FORUM OF INDIA [SEFI]

 Forum SubscriptionsSubscriptions DigestDigest Preferences   FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups  RegisterRegister FAQSecurity Tips FAQDonate
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log in to websiteLog in to websiteLog in to websiteLog in to forum 
Warning: Make sure you scan the downloaded attachment with updated antivirus tools  before opening them. They may contain viruses.
Use online scanners
here and here to upload downloaded attachment to check for safety.

Indian codes do not encourage economy in design

 
This forum is locked: you cannot post, reply to, or edit topics.This topic is locked: you cannot edit posts or make replies.    www.sefindia.org Forum Index -> E-Conference 1st June 2003
View previous topic :: View next topic  
Author Message
roark.sol1
Diamond Sponsor
Diamond Sponsor


Joined: 26 Jan 2003
Posts: 70

PostPosted: Mon Jul 21, 2003 2:58 pm    Post subject: Indian codes do not encourage economy in design Reply with quote

Hello All,

Copied below is the edited text of a posting I had made on the general
discussion forum on March 17, which will be more topical in this
e-Conference :
*******************

1) A lot of clauses in the Indian codes in general and 1893:2002 in
specific, are ambiguous and open ended which lead to multiple
interpretations. I do not know, why this is so, but it is a very undesirable
situation, and should be dealt with head on (in no ambiguous terms). One of
the objectives of this forum is to
facilitate this process, firstly by providing a platform to discusss the
different views & interpretations with the aim of acheiving a convergence of
the same, and secondly to form an effective pressure group to acheive the
implementation of the converged views & interpretations.

2) In cases of ambiguity, the general response in most of the cases is to
nterpret it towards the CONSERVATIVE side, without application of either
rational & scientific thought process or effort to discuss with peers. This
seems to have become an underlying definition of a structural engineer. I
know that this phenomenon is due to poor economic compensation for their
time & efforts, but it will ultimately lead to increasing marginalization of
the structural engineer in todays fast developing world and thus increasing
reduction in the compensation. If safety & conservatism is the only
principle on which to operate, then we will not be needed, because our need
to the society is governed by our ability to "optimize between safety &
economy", and I see the current trend leading more & more towards safety
leaving economy to the winds. A classic case is this topic of load
combinations. If we consider the UBC 1997, we will see that all the load
combinations given (clause 1612.2.1, page 2-4, vol II) are far less
conservative than those given in Indian codes, and the reason being that
they are far more scientifically rational & logical, and not based on an
irrational fear for "lack of safety".

3) Our codes are pathetically lacking the adequacy to meet the requirements
of the new millenium. They seem to have an ostrich like attitude towards
computerized calculations and their ability to provide optimizations in a
short time frame. Just because ALL of us in India do not have the means to
have the right tools or are not ready to apply their minds & efforts, should
not be a reason for a penalty to those who have the tools and are
effectively using them to create a more rational & economical structural
system. The present day formulations, clauses & guidelines of the Indian
codes DO put such a penalty, specially in the cases of peer review &
checking by government engineers. Again a classic case is the emperical
formulae for time period of the building "WITHOUT infill panels" as given in
IS:1893:2002 opposed to the results you get by ANY software. "WITH the
panels" case may be debatable to some extent, but "WITHOUT the panels" case
has no justification of being so outrightly unconservative in the year 2002.

I sincerely hope that this forum will be instrumental in addressing these
issues and in finding solutions to the inadequacies we currently face.

********************
Regards

Pankaj Gupta

Posted via Email
Back to top
View user's profile Send private message
roark.sol1
Diamond Sponsor
Diamond Sponsor


Joined: 26 Jan 2003
Posts: 70

PostPosted: Mon Jul 21, 2003 5:40 pm    Post subject: Indian codes do not encourage economy in design Reply with quote

Dear Alpa,

Comments on 2 of your points

Quote:
I thought the Indian load combinations are pretty much on par with those
elsewhere if one takes into account the ultimate vs limit load systems
of design.

Consider UBC load case for DL+LL which is 1.2DL+1.6LL which is based upon
the logic that the probability of LL exceeding the prescribed value is much
higher than DL. Also a rough calculation on typical load values of 10 KN/sqm
of DL & 3 KN/sqm of LL will give a combination of 16.8 KN/sqm versus 19.5
KN/sqm as per 1.5DL+1.5LL. And these values are for limit state. Using 1.5
for DL is very conservative. The British & Euro codes also use lesser
factors for DL in comparison to LL.


Quote:
The requirement of empirical formulae for time period is based on
hundreds of in-situ testing and exists  even in IBC for that matter. ANd
then don't you think building loads keep changing over the liftime of a
building? Walls are knocked off or built, changing stiffness to a large
degree without any thought. So it does make sense to have empirical
formulae....

That is why I said that the value for the "WITH infill panel" case may be
debatable. But what is the logic for using such a conservatively high value
for  "WITHOUT infill panel" case, and that too in 2002, when more accurate
tools are available. Using such values in 1984 was OK, but they are
ostrichidal in 2002.

In general there is no limit to being conservative, and we are way tooooo
conservative. How can we turn a blind eye to the fact that 99% of Indian
structures built in Indian cities do not comply even by 50% of the codal
design procedures even for only gravity loads, but still survive for as
long. We as SEs deal in scientific methods, which is based upon experiments
& observation. The Indian public in all their ignorance is continuously
conducting grand experiments so we can observe, but we only FEAR and do not
learn. And if one building out of millions of such buildings fail or
collapse, we start patting our backs that we were right in being so
conservative.

By saying this I am not advocating that codal design procedures should not
be followed, but what I am saying is that the code-developers should not
ignore this fact & learn from this absolutely amazing phenomenon that they
are being much tooooooo conservative in their prescriptions.

Regards

Pankaj

Posted via Email
Back to top
View user's profile Send private message
Display posts from previous:   
This forum is locked: you cannot post, reply to, or edit topics.This topic is locked: you cannot edit posts or make replies.    www.sefindia.org Forum Index -> E-Conference 1st June 2003 All times are GMT
Page 1 of 1

 

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum


© 2003, 2008 SEFINDIA, Indian Domain Registration
Publishing or acceptance of an advertisement is neither a guarantee nor endorsement of the advertiser's product or service. advertisement policy