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.

Why do designs by different structural engineers vary so gre
Goto page Previous  1, 2
 
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> SEFI General Discussion
View previous topic :: View next topic  
Author Message
amarjeetsingh
...
...


Joined: 09 Nov 2008
Posts: 130
Location: new delhi

PostPosted: Mon Sep 28, 2009 6:56 am    Post subject: Why do designs by different structural engineers vary so gr Reply with quote

dear all,
 
as mentioned by sir, the analysis and design of structures is a combination of science and art. even with the same framing plan and the same analysis results the art lies in the detailing of the reinforcement. the detailing varies from engineer to engineer, his interpetation of the load transfer system from the slabs to the foundation.
 
the various responses make it clear that we as an educated persons are willing to agree to disagree on this matter.
 
regards
 
amarjeet singh

 
On 9/28/09, uhvaryani <forum@sefindia.org (forum@sefindia.org)> wrote:
Quote:
  Dear Sefians,
Many thanks to our regular and respected respondents for their
valuable views on this subject.As structural engineering is a science
as well as an art,two engineers may have
different views.As no two doctors agree,so also engineers may give
different designs for a given building.When the soil properties are
different and earthquake zones are different,
it is natural to expect to have different designs.There is no
difference of opinion on this aspect.But,when the site is the
same,then also we find widely varying designs of similar types of
buildings.This is quite disturbing.The main reason may be that some
engineers design buildings only for vertical loads and do not consider
horizontal loads like earthquake and wind.When you go around new
residential colonies,many buildings are coming up with column steel
bars showing up.Columns in some buildings are heavily reinforced,while
in other buildings,columns are lightly reinforced.This clearly
indicates that designers have not considered horizontal loads where
the columns are lightly reinforced.
In an existing design of a 4-storeyed library building,the concerned
designer told me(a long while back) that he had designed the building
for vertical loads only and he had not considered earthquake as it was
only 4 storeys in height.Earthquake causes movement of earth and it
obviously does not know the number of storeys of structures standing
on earth.All buildings of whatever storeys should be checked for
earthquake forces.The difference in steel consumption in similar
buildings is mainly on this account,in my view.
I have written a paper on this subject and it is published in
ICJ,August,2001 and the same is reproduced in my book on
multi-storeyed buildings.
with best wishes and regards,
uhvaryanidesigner








Posted via Email
Back to top
View user's profile Send private message Visit poster's website
uhvaryani
General Sponsor
General Sponsor


Joined: 21 May 2008
Posts: 250

PostPosted: Thu Oct 08, 2009 12:44 pm    Post subject: Why do designs by different structural engineers vary so gre Reply with quote

Dear Er.Amarjeet Singh,
I am an ardent admirer of your
postings on the forum.I request
you to please give me your e-mail
id and also your telephone number
so that we may remain intouch at a personal level.
many thanks and regards,
uhvaryani
e-mail id :uhvaryani@gmail.com
Tel no. 011-26893516

Posted via Email
Back to top
View user's profile Send private message
patiilgr
SEFI Member
SEFI Member


Joined: 26 Jan 2003
Posts: 3

PostPosted: Fri Oct 09, 2009 7:27 am    Post subject: Why do designs by different structural engineers vary so gre Reply with quote

--- On Thu, 8/10/09, uhvaryani <forum@sefindia.org> wrote:

Quote:
From: uhvaryani <forum@sefindia.org>
Subject: [SEFI] Re: Why do designs by different structural engineers vary so gre
To: general@sefindia.org
Date: Thursday, 8 October, 2009, 6:19 PM







      da

     Dear Er.Amarjeet Singh,

I am an ardent admirer of your

postings on the forum.I request

you to please give me your e-mail

id and also your telephone number

so that we may remain intouch at a personal level.

many thanks and regards,

uhvaryani

e-mail id :uhvaryani@gmail.com

Tel no. 011-26893516

     






     

Dear
SEFIANS

We are in need of codes preferably Indian stadards on high strength as reg
ards, accepaance criteria design procedure etc. How this standards vary from American and British Standard.


From cricket scores to your friends. Try the Yahoo! India Homepage! http://in.yahoo.com/trynew

Posted via Email
Back to top
View user's profile Send private message
info.vdss
SEFI Regulars
SEFI Regulars


Joined: 30 Sep 2009
Posts: 21

PostPosted: Fri Oct 09, 2009 7:57 am    Post subject: Reply with quote

dear all Sefians,
  
The design of structures is a science and art its true and in my view the second part of it makes a lot of difference in the design of the same structure.

In brief I would like to point out some of the reasons for varying designs

1.  In the same plan the position of the Columns decided by different SEs will  greatly affect the design and its economics altogether.

2. The way of analysing the structure whether it is considered as a bare frame or the brick infills have also been considered. whether floor diaphragmhave been considered in analysis or not etc. etc.

3. The selected foundation system will also vary from person to person hence, causing a ot difference.

4. Some SEs will adopt centreline forces for their design while others calculate these forces and moments at the section meant for design

5. The end conditions assumed by SEs of some of the structural members  may vary causing huge difference in the design.

6. The orientation of the columns at some locations will also made difference.

7. and last but not the least reason for the variation in the design is the thought of the concern architect. Some time some architects takes the things casually and they make minor structural changes in the structures at the letter stages, even they sometimes avoid a column,  thus compelling the structural engineer for oversafe design causing variation in the design.
  
Regards and thanks a lot to shri Varyani Sir for initiating this topic
  
Narendra Shekhawat
Back to top
View user's profile Send private message
abhy_vivek
Silver Sponsor
Silver Sponsor


Joined: 26 Jan 2003
Posts: 675
Location: Andheri (E), Mumbai

PostPosted: Fri Oct 09, 2009 10:40 am    Post subject: Why do designs by different structural engineers vary so gre Reply with quote

Dear Shri,

Varyaniji,

I wish to purchase your all books and need copy of all your 40 Papers.
How to get the same ?

Regards
Vivek Abhyankar
abhy_vivek@yahoo.com

Mumbai



Try the new Yahoo! India Homepage. Click here. http://in.yahoo.com/trynew

Posted via Email
Back to top
View user's profile Send private message
KSushil
SEFI Member
SEFI Member


Joined: 20 Oct 2009
Posts: 2

PostPosted: Tue Oct 20, 2009 12:01 pm    Post subject: Reply with quote

Dear Mr Shekhawat,

I think that while your answers succeed in answering the original poster's queries, they also highlight a problem in our profession, that results in these needless variations.

I can understand the variations due to spans, column locations/ orientations, foundation soils, sesmic zones etc, but the below quoted  reasons are a weakness in the profession I believe:

I believe that the bullets nos 2, 4 and 5 are not just the difference of opinion. They WILL make a difference in the safety/economy of the structure. One will be designing a safe structure, but another will either design weak, or unnecessarily Oversafe structure. I belong to the "Safety, then Economy" group, so i mostly go for the heavier alternative when faced with this dilemma. I just wish the dilemma will be clarified sooner.

As for 3, I believe that it is our responsibility to go for the most economic foundation, provided it is safe. I have seen designers opting for Raft, even when a grid foundation would have fulfilled the requirements at half the cost. After all it is the client who will pay.

About 6 and 7, they are an architect's prerogative, and we can only follow the drawings and make them stable. I only find it unforgivable, if a SE himself uses wrongly oriented columns in the design.

Sorry, if i sound argumentative, but I am trying to expand on the OP's questions and to examine ourselves critically, like the posters before me.

To be explicit, Yes there is diversity in designs. Sometimes they are due to the architectural design AND sometimes due to the various structural theories being followed, BUT a significant reason in the laziness/ineptitude of the SE's themselves. And the last is the one that many SEs donot want to face.

[quote="info.vdss"]dear all Sefians,
  

2. The way of analysing the structure whether it is considered as a bare frame or the brick infills have also been considered. whether floor diaphragmhave been considered in analysis or not etc. etc.

4. Some SEs will adopt centreline forces for their design while others calculate these forces and moments at the section meant for design

5. The end conditions assumed by SEs of some of the structural members  may vary causing huge difference in the design.



3. The selected foundation system will also vary from person to person hence, causing a ot difference.

6. The orientation of the columns at some locations will also made difference.

7. and last but not the least reason for the variation in the design is the thought of the concern architect. Some time some architects takes the things casually and they make minor structural changes in the structures at the letter stages, even they sometimes avoid a column,  thus compelling the structural engineer for oversafe design causing variation in the design.
Back to top
View user's profile Send private message
ssv
SEFI Regulars
SEFI Regulars


Joined: 17 Sep 2009
Posts: 21

PostPosted: Wed Oct 21, 2009 2:41 am    Post subject: Reply with quote

Dear Varyani sir,

I too need the copy of your papers and your books "Design Aids for Limit State Design of Reinforced Concrete Members" & "A manual of limit state design of reinforced concrete members". this books are not available in shops at my place.

Please make some arrangement.

Regards
ssv

sri_visvas@yahoo.co.in
Back to top
View user's profile Send private message
shiven2004
...
...


Joined: 08 Oct 2009
Posts: 115
Location: NEW DELHI

PostPosted: Wed Oct 21, 2009 9:18 am    Post subject: variation of design Reply with quote

Engineering is look as an exact science, that if correct procedure are followed then all the designs would be same, but the answer is opposite.

even if we take all the formullas into consideration, there is still lot of areas let, where our engineering field acts like an art.

consider the bearing capacity,

now you will be given that , a given place has a bearing capacity of 150 , and now you have to decide whether you would give a Mat foundation, combined footing or spread footing.

now , while making decision, the code will give you a certain limitation, about the footing, and your contractor will give you certain monetary framework to work with.

taking all this consideration, and taking intution into play, you get the structure, which is more of an art then a science.

to say, in my mentor language.

Codes and formullas are the rules of the game, but the game is played by the designer, so every "Goal" is different, albeit the rules are the same
Back to top
View user's profile Send private message Visit poster's website
suraj
General Sponsor
General Sponsor


Joined: 17 Apr 2008
Posts: 1988
Location: NCR Faridabad, E mail suraj_engineer@yahoo.co.uk

PostPosted: Wed Oct 21, 2009 3:29 pm    Post subject: Design is a Structured architecture Reply with quote

Design is a Structured architecture

Civil Engineering designs can be related to Scientific Art based applications. Structural Imaginations!!!

Based on set principles & procedures of analysis & designs, the design decisions are taken & adopted on constructions keeping in view other factors as well as, that more or less, relate further to the executive circumstances & virtual enviornment.

Codes are devised in a regulatory acceptance but, by the varying inputs of engineering, scientific & material community in additon to the constructing community involvements. All codes devisers possess different background experiences.

No one is responsible there who are involved with codes formulations.
Codes should not be considered exclusively as an exclusive statutory rule but, an instrument to be supported with, for clear guidance & design research.

Designer is expected to ensure 'calculated for adequate safety' while the design decisions are made. Designer is responsible for the designs & not the codes. One who signs any drawings is held liable by the court of law in case of problems leading to casulaties.

It is too significant on the part of any designer to have patience throughout & produce design competenctly safe in all conditions of its use. Soil plays too important a role & neither soil nor the materials comply to the assumptions made in engineering. Even, the structures vary the assumed loading conditions.

What factor of safety are to be applied to the result of the bearing capacity is a big question mark? It varies from 3 to 5 depending on the nature of soils.

Structure design is a scientific art & an architecture to integrate with the artistic art of occult based architecture. It is an amalgamation whether it be external or it be internal art as elevations.

Regards

_________________
Thanks & Warm Regards
IntPE(India)Suraj Singh FIE Civil
Engineering & Arbitration

Back to top
View user's profile Send private message Visit poster's website
sher khan
...
...


Joined: 04 Jun 2008
Posts: 58

PostPosted: Wed Oct 21, 2009 7:46 pm    Post subject: Reply with quote

if all the design parameters are same for any two identical structures then there exists  one and only one economical structural design
                                                                     KHAN
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topicReply to topic Thank Post    www.sefindia.org Forum Index -> SEFI General Discussion All times are GMT
Goto page Previous  1, 2
Page 2 of 2

 

 
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 cannot 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