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nvnagaraju SEFI Member
Joined: 30 Jul 2008 Posts: 8
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Posted: Thu Jan 10, 2013 6:53 am Post subject: Proposed REVISION OF IS:456-2000- Inviting Comments |
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Dear Sir,
Anchoring requirement of concrete needs to be included in IS 456 specifying tensile loading, shear loading, edge distance, thickness to prevent splitting failure as specified in ACI code. Is 456 should throw light on strut and tie modeling which will be very useful in analytical modeling of shear walls, pile caps, etc., elements. Shear and torsion requirement to be elaborated for corbel/bracket, deep beams, walls, etc.,
Regards,
N V Nagaraju
From: Dr. N. Subramanian [mailto:forum@sefindia.org] ([mailto:forum@sefindia.org])
Sent: Tuesday, January 08, 2013 9:30 PM
To: general@sefindia.org (general@sefindia.org)
Subject: [SEFI] Proposed REVISION OF IS:456-2000- Inviting Comments
Dear All,
I came to know from Mr Sanjay Pant, Director (Civil Engineering)
Bureau of Indian Standards, that they are going to take up the revision of IS 456 soon. Hence our Er Mallick proposed the idea of collecting comments from our SEFIans, which can be passed on to BIS. Hence I am starting this Tread. Please post your comments only in this tread and not in several other places.
Best wishes,
Subramanian
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Manoharbs_eq General Sponsor
Joined: 17 Jul 2012 Posts: 423
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Posted: Thu Jan 10, 2013 8:01 am Post subject: |
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Dear sir
Few more points to be included would be
1) Rigid and flexible diaphragm definition
2) Difference between column and shear wall based on L/B ratio of column.
3)Clause 32.5 minimum reinforcement is Rc wall shall be updated.
4)Pre cast concrete structures are now becoming more so some details and design procedure shall be included in 30.8 clause.
5) Revision for clause 31 for flat slabs shall be included for flat slab with end beams and without. |
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bijoyav ...
Joined: 13 Dec 2008 Posts: 111
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Posted: Thu Jan 10, 2013 8:19 am Post subject: |
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I wish all the IS codes are available free of cost, in digital format, in BIS website....... Why should Govt make revenue from the cost of IS Code?.... Let people use IS Codes more
Bijoy AV |
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harshaldalal SEFI Member
Joined: 18 Oct 2012 Posts: 4
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Posted: Thu Jan 10, 2013 9:06 am Post subject: Proposed REVISION OF IS:456-2000- Inviting Comments |
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Respected Sir,
I have compared different country's codal provisions with IS 456-2000 with respect to durability,and i found that indian code is lacking in some of the factors from other country codes. which are as follows.
1.The existing classification of exposure classes in IS 456:2000 (Table 2), which is based on arbitrary definitions in categories such as mild, moderate, severe, very severe and extreme classes, seems inadequate and restrictive as compared to other international codes.
Such definitions certainly need to be expanded and made more rational.
2., All codes gave their requirements of minimum cover depending up on the grade of concrete being used and exposure conditions.
But, Australian code has considered the workmanship in the form of form work and compaction of concrete in addition of exposure conditions and grade of concrete to give their requirement of minimum cover which is a very good practice and it should be added in Indian Standard.
Thank You
Harshal Dalal
Surat
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kappi General Sponsor
Joined: 05 May 2009 Posts: 58
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Posted: Thu Jan 10, 2013 10:45 am Post subject: |
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Dear Sefians,
In my view, Clauses on Precast design should be emphasized.
Regards,
Er. Kapil Chawla |
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srinivasan_vasudevan SEFI Member
Joined: 27 Jul 2010 Posts: 11
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Posted: Thu Jan 10, 2013 2:52 pm Post subject: Proposed REVISION OF IS:456-2000- Inviting Comments |
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dear sefians
my comments are as below
1. we should have a clause on "detailing for integrity" which essentially explains how the re bars should be placed at intersection of members
a.) beam column junction b) minimum bars to pass through columns in the column strip of flat slab C) minimum column sizes for multi storied buildings shall not be less than 300mm D)
2. minimum grade of concrete shall be M25
3. a clause on self compacting concrete can be added
consulting engineer
vasudevan t s
On Thu, Jan 10, 2013 at 11:59 AM, va <forum@sefindia.org (forum@sefindia.org)> wrote:
Quote: | Dear SEFIans,
1) We should have some minimum width of column like 300mm ( like American code) to improve detailing at beam column junction.( Considering general building beam width is 200 or 230mm) . Column width should be more than beam width for proper detailing.
2) Maximum column reinforcement 4% is not practical to execute at site. Recommended reinforcement should be about 2.5% to avoid congestion.
3) A chapter on “Constructability” can be added considering construction aspects of RCC elements. Like special confining reinforcement in columns and beam column junctions, heavy congestion of reinforcement at junctions of beam / column, problems in design of connecting member for coupled shear walls, deep beam construction in layers and stages, several aspects addressing difficulty faced at site by the execution team. Good engineering practices in design and execution.
Hemant Vadalkar
Consulting Engineer Mumbai.
From: Dr. N. Subramanian [mailto:forum@sefindia.org (forum@sefindia.org)]
Sent: Tuesday, January 08, 2013 9:30 PM
To: general@sefindia.org (general@sefindia.org)
Subject: [SEFI] Proposed REVISION OF IS:456-2000- Inviting Comments
Dear All,
I came to know from Mr Sanjay Pant, Director (Civil Engineering)
Bureau of Indian Standards, that they are going to take up the revision of IS 456 soon. Hence our Er Mallick proposed the idea of collecting comments from our SEFIans, which can be passed on to BIS. Hence I am starting this Tread. Please post your comments only in this tread and not in several other places.
Best wishes,
Subramanian
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Dr. N. Subramanian General Sponsor
Joined: 21 Feb 2008 Posts: 5538 Location: Gaithersburg, MD, U.S.A.
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Posted: Thu Jan 10, 2013 3:47 pm Post subject: |
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Dear Er Bijoy,
BIS is a separate organization,may be Quasi Govt. and has its own budget. It has its own offices in different cities and each office has its own staff too. Producing a code is a time consuming and costly affair.
Of course, I agree that BIS has increased the cost of the codes enormously in recent times. I think IS 456 and 800 are about Rs. 1350, whereas the elaborate books that explain these clauses with several examples, and having 5 to 8 times the number of pages cost around Rs 500 to Rs 800 only.
ACI codes and publications are also expensive. I just received the 2013 catalog of ACI Publications. ACI 318 costs $192.50 for its 503 pages volume. That means each page is $ 0.38. Whereas IS 456 costs Rs 1,190 for its 100 pages-Rs.11.90 per page. According to me the conversion should be Rs. 10 per $. Hence the reasonable cost as compared to ACI should be Rs.3.80 per page or the code should not be priced more than Rs. 380. The most funniest part is that BIS cost of the same code purchased outside India is Rs. 11,900! Some ACI publications are very expensive, although ACI has student concession. I think such student concession is there for BIS codes also. BIS codes can also be purchased online:http://www.standardsbis.in/Gemini/home/Home.action#
The only organization which is supplying its code online free of cost is AISC. Of course the printed codes are priced nominally around $25. But AISC is subsidized by the Steel industry.
Best wishes,
Subramanian
bijoyav wrote: | I wish all the IS codes are available free of cost, in digital format, in BIS website....... Why should Govt make revenue from the cost of IS Code?.... Let people use IS Codes more
Bijoy AV |
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Dr. N. Subramanian General Sponsor
Joined: 21 Feb 2008 Posts: 5538 Location: Gaithersburg, MD, U.S.A.
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Posted: Thu Jan 10, 2013 4:05 pm Post subject: Re: Proposed REVISION OF IS:456-2000- Inviting Comments |
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Dear Friends,
With reference to the comments by Er Hemal Mistry and Er Sangeetaji, I wish to comment like this. Although an explanatory handbook exists in the form of SP 24:1983, this is based on the 1978 version of the code. Also many are not aware of this handbook at all. Hence, it will be better to combine both, just like ACI 318, and bring them as a single volume.
It is important to upgrade SP 16 and SP 34 also on par with the modifications done in IS 456.
Why not our codes contain an Index? As the volume increases, it is necessary to have an index. ACI 318 has an index!
I think Indian Concrete Institute(ICI) should gear up and bring at least special publications on Torsion, Shear, Joints, Shrinkage, Creep, etc., like the ACI (My dream is that ICI should publish codes like ACI). as a first step they may enter into some agreement with ACI and bring Indian editions of these publications, which are priced reasonably.
Best wishes,
Subramanian
[quote="SANGEETA WIJ"]Dear Mr Mistry
You have raised a very valid point and I also feel the Code should illustrate some examples of a rigid connection, pinned connection, partially fixed connection and so on, at the column-foundation joint as well as a Beam-Column junction. I have checked some designs where the drawings are released with incorrect Joint details which are not corresponding to the assumptions made during analysis. If illustrated, the details will help our engineers to understand them and co-relate with analysis better.
Regards
Sangeeta Wij |
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Dr. N. Subramanian General Sponsor
Joined: 21 Feb 2008 Posts: 5538 Location: Gaithersburg, MD, U.S.A.
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Posted: Thu Jan 10, 2013 4:20 pm Post subject: Re: Proposed REVISION OF IS:456-2000- Inviting Comments |
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Dear All,
I have written a few papers in which I have compared the IS provisions or the lack of it with other codal provisions and suggested some provisions. They are listed below:
- Subramanian N., Shear strength of high strength concrete beams: Review of Codal Provisions, The Indian Concrete Journal, V.77, No.5, May 2003, pp.1090-1094.
- Subramanian, N., Evaluation and Enhancing the Punching Shear Resistance of HSC Flat Slabs, The Indian Concrete Journal, Vol.79, No.4, April 2005,pp.31-37.
- Subramanian, N., Development length of Reinforcing Bars – Need to Revise Indian Code Provision, The Indian Concrete Journal, Vol. 79, No.8, Aug. 2005, pp.39-46, Discussion, Oct. 05, pp.22.
- Subramanian, N., Controlling the crack width of Flexural R.C. Members, The Indian Concrete Journal, Vol.79, No.11, Nov. 2005, pp.31-36
- Subramanian, N., Transmission of HSC column loads through NSC slabs, The Indian Concrete Journal, Vol.80, No.1, Jan 2006, pp.44-49.
- Subramanian, N., Effective Concrete Strength of Column - Slab/Beam Joints, Bulletin of the Indian Concrete Institute, No.65, Oct.-Dec. 98, pp. 29-31.
- Subramanian, N., Limiting reinforcement ratios for RC flexural members, The Indian Concrete Journal, Vol. 84, No.9, Sept.2010, pp.71-80
- Subramanian, N., Design of confinement reinforcement for RC columns, The Indian Concrete Journal, Vol. 85, No.8, Aug.2011, pp.25-36.
- Subramanian N., Curing – The Last and the Least Considered Aspect in Concrete Making, Journal of the Indian Concrete Institute,Vol.3, No.1, April–June 2002, pp.13-20.
- Subramanian N., and Prakash Rao., D.S., Seismic Design of Joints in R.C. Structures – A Review, The Indian Concrete Journal,Vol.77, No.2, Feb.2003, pp.883-892.
The committee should consider the recommendations suggested by me.
Best wishes,
NS |
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Dr. N. Subramanian General Sponsor
Joined: 21 Feb 2008 Posts: 5538 Location: Gaithersburg, MD, U.S.A.
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Posted: Thu Jan 10, 2013 4:52 pm Post subject: Re: Proposed REVISION OF IS:456-2000- Inviting Comments |
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Dear Friends,
As suggested by many, it is high time IS 456 includes provisions on Anchor bolts, as in Appendix D of ACI 318. Prof. Rolf Elgehausen of the University of Stuttgart has spent his life time on the design of Anchor bolts- i was fortunate to visit his Lab during 1991, when I attended a conf. organized by IABSE. Even ACI has used his services to develop Appendix D of ACI 318. There are many others like Prof. Cook,Prof. Klingner, R.Cannon, R. Mallée, J. Zhao, Er Richard E. Wollmershauser and Er J. Silva of Hilti, Dr W Fuchs, and others who have contributed in this field extensively. I have written the following papers which may be useful in developing the code clauses.
- Subramanian, N., Recent Developments in the Design of Anchor Bolts, The Indian Concrete Journal, V. 74, No. 7, July 2000, pp. 407-414
- Subramanian, N., and Cook, R.A., Installation, Behaviour and Design of Bonded Anchors, The Indian Concrete Journal, Vol. 76, No. 1, Jan. 2002, pp. 47-56
- Subramanian N., and Cook R.A., Behaviour of Grouted Anchors, The Indian Concrete Journal, Vol.78, No.4, April 2004, pp.14-21 Reply to the Discussion, Vol.78, No.12, Dec.2004, pp.12
Best wishes,
NS |
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