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alpa_sheth ...
Joined: 26 Jan 2003 Posts: 281
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Posted: Thu Feb 19, 2004 1:26 pm Post subject: Column Rings |
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Dear All,
I was wondering how others are dealing with the dichotomy on the column ring requirements of IS 456 and IS 13920 For Column rings, IS 456-2000 insists that a cross tie is required for column bars when the spacing of the bars exceeds or equals 75mm (Fig . On the other hand IS 13920-1993, requires a cross tie when the column bar spacing is equal to or greater than 300mm. ACI 318-02 is also more on the lines of IS 13920 than IS 456 which I feel is unduly punitive. One would expect IS 456 to be less stringent than IS 13920.
If others feel alike, I thought we could, as a group of structural engineers, make a representation to BIS to issue an amendment to IS 456 correcting this requirement for cross ties in columns. I suggest that if there are enough emails regarding this we could send all of them to BIS. May I request those who want to comment on this issue on SEFI to also append their details re. address, co etc. in their emails.
Regards, Alpa Sheth Vakil Mehta Sheth Consulting Engineers 312 Apeejay House 130 B S Marg Mumbai 400 023
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rgassociates SEFI Member
Joined: 26 Jan 2003 Posts: 9
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Posted: Thu Feb 19, 2004 3:05 pm Post subject: Column Rings |
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Dear Madam Alpha,
As a structural engineer I am with you. Kindly make the representation to get the amendment.
Wish you success,
T.Rangarjaan ----- Original Message ----- From: <alpa_sheth@vakilmehtasheth.com> To: <rgassociates@eth.net> Sent: Thursday, February 19, 2004 6:56 PM Subject: Column Rings
Dear All,
I was wondering how others are dealing with the dichotomy on the column ring requirements of IS 456 and IS 13920 For Column rings, IS 456-2000 insists that a cross tie is required for column bars when the spacing of the bars exceeds or equals 75mm (Fig . On the other hand IS 13920-1993, requires a cross tie when the column bar spacing is equal to or greater than 300mm. ACI 318-02 is also more on the lines of IS 13920 than IS 456 which I feel is unduly punitive. One would expect IS 456 to be less stringent than IS 13920.
If others feel alike, I thought we could, as a group of structural engineers, make a representation to BIS to issue an amendment to IS 456 correcting this requirement for cross ties in columns. I suggest that if there are enough emails regarding this we could send all of them to BIS. May I request those who want to comment on this issue on SEFI to also append their details re. address, co etc. in their emails.
Regards, Alpa Sheth Vakil Mehta Sheth Consulting Engineers 312 Apeejay House 130 B S Marg Mumbai 400 023
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Jayant Lakhlani General Sponsor
Joined: 26 Jan 2003 Posts: 192
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Posted: Fri Feb 20, 2004 4:48 am Post subject: Column Rings |
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Dear Alpa,
I agree in making a representation to BIS. But instead of making a group who feel alike, cant we do that we try to search for technical logic behind provisions in IS : 456 and 13920, and that behind ACI provisions and provisions in other codes also.
We can have a discussion among ourselves on those different logic to reach a conclusion with sound technical justification supporting it and then we can represent that to BIS along with the technical justification.
I think suggestion with a technical justification will make more sense rathr than to suggest what we feel like.
I think along with this point, IS - 13920 provision for confining ties in columns can also be considered.
Regards..
JAYANT LAKHLANI Consulting Engineers 221/223, SILVER CHAMBER TAGORE ROAD RAJKOT
alpa_sheth@vakilmehtasheth.com wrote: Dear All,
I was wondering how others are dealing with the dichotomy on the column ring requirements of IS 456 and IS 13920 For Column rings, IS 456-2000 insists that a cross tie is required for column bars when the spacing of the bars exceeds or equals 75mm (Fig . On the other hand IS 13920-1993, requires a cross tie when the column bar spacing is equal to or greater than 300mm. ACI 318-02 is also more on the lines of IS 13920 than IS 456 which I feel is unduly punitive. One would expect IS 456 to be less stringent than IS 13920.
If others feel alike, I thought we could, as a group of structural engineers, make a representation to BIS to issue an amendment to IS 456 correcting this requirement for cross ties in columns. I suggest that if there are enough emails regarding this we could send all of them to BIS. May I request those who want to comment on this issue on SEFI to also append their details re. address, co etc. in their emails.
Regards, Alpa Sheth Vakil Mehta Sheth Consulting Engineers 312 Apeejay House 130 B S Marg Mumbai 400 023
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Jayant Lakhlani General Sponsor
Joined: 26 Jan 2003 Posts: 192
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Posted: Fri Feb 20, 2004 4:48 am Post subject: Column Rings |
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Dear Alpa,
I agree in making a representation to BIS. But instead of making a group who feel alike, cant we do that we try to search for technical logic behind provisions in IS : 456 and 13920, and that behind ACI provisions and provisions in other codes also.
We can have a discussion among ourselves on those different logic to reach a conclusion with sound technical justification supporting it and then we can represent that to BIS along with the technical justification.
I think suggestion with a technical justification will make more sense rathr than to suggest what we feel like.
I think along with this point, IS - 13920 provision for confining ties in columns can also be considered.
Regards..
JAYANT LAKHLANI Consulting Engineers 221/223, SILVER CHAMBER TAGORE ROAD RAJKOT
alpa_sheth@vakilmehtasheth.com wrote: Dear All,
I was wondering how others are dealing with the dichotomy on the column ring requirements of IS 456 and IS 13920 For Column rings, IS 456-2000 insists that a cross tie is required for column bars when the spacing of the bars exceeds or equals 75mm (Fig . On the other hand IS 13920-1993, requires a cross tie when the column bar spacing is equal to or greater than 300mm. ACI 318-02 is also more on the lines of IS 13920 than IS 456 which I feel is unduly punitive. One would expect IS 456 to be less stringent than IS 13920.
If others feel alike, I thought we could, as a group of structural engineers, make a representation to BIS to issue an amendment to IS 456 correcting this requirement for cross ties in columns. I suggest that if there are enough emails regarding this we could send all of them to BIS. May I request those who want to comment on this issue on SEFI to also append their details re. address, co etc. in their emails.
Regards, Alpa Sheth Vakil Mehta Sheth Consulting Engineers 312 Apeejay House 130 B S Marg Mumbai 400 023
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Jayant Lakhlani General Sponsor
Joined: 26 Jan 2003 Posts: 192
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Posted: Fri Feb 20, 2004 5:30 am Post subject: COLUMN RINGS |
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Dear Alpa,
I agree in making a representation to BIS. But instead of making a group who feel alike, cant we do that we try to search for technical logic behind provisions in IS : 456 and 13920, and that behind ACI provisions and provisions in other codes also.
We can have a discussion among ourselves on those different logic to reach a conclusion with sound technical justification supporting it and then we can represent that to BIS along with the technical justification.
I think suggestion with a technical justification will make more sense rather than to suggest what we feel like.
I think along with this point, IS - 13920 provision for confining ties in columns can also be considered.
Regards..
JAYANT LAKHLANI Consulting Engineers 221/223, SILVER CHAMBER TAGORE ROAD RAJKOT
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sjgandhi SEFI Regulars
Joined: 26 Jan 2003 Posts: 20
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Posted: Fri Feb 20, 2004 7:21 am Post subject: Column Rings |
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Dear Alpa,
I support the deliberations you have raised as the provisions of links have become controversial at site and among designers after the January 2001 earthquake.
I feel that we should represent the BIS on following points regarding column links as per IS:456 & IS:13920.
1. Type of steel to be used in links:
Same grade & type of steel shall be used for links as per main vertical bars.
2. Minimum dia. of links: As per IS:456 but not less than 8 mm dia
3. Minimum amount of transverse reinforcements:
[A] IS:456: To be retained as per the relevant clause IS:13920: To be classified as per seismic zone factors Z or design horz. seismic coefficient Ah. i.e intensity of seismic hazards. In portion of column with special confining reinforcement the amount of horiz. links to be progressively increasing as Z or Ah increases with the aid of some empirical formula.
4. Provision of cross ties:
Both IS:456 & IS:13920 should advocate same identical provisions without ambiguity.
5. Lapping of column bars:
Lapping of all the bars at same location may be allowed depending upon the intensity of seismic hazards classifying low risk, moderate risk & high risk.
Regards,
Sunil Gandhi Consulting Structural Engineer. 108, Amrut Commercial Centre, Sardarnagar Main Road, Rajkot-360001 --------------- Ph:(0281)2467661
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gyan_th Progressive Member
Joined: 26 Jan 2003 Posts: 40
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Posted: Fri Feb 20, 2004 12:32 pm Post subject: Column Rings |
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Deal All,
I agree with Miss Seth's idea that one expects IS-456 to be less stringent than IS-13920.
Gyaneshwar Th. Sr. Project Executive, NBCC Ltd.
Quote: | From: alpa_sheth@vakilmehtasheth.com Reply-To: general@sefindia.org To: gyan_th@hotmail.com Subject: Column Rings Date: Thu Feb 19 18:56:17 2004
Dear All,
I was wondering how others are dealing with the dichotomy on the column ring requirements of IS 456 and IS 13920 For Column rings, IS 456-2000 insists that a cross tie is required for column bars when the spacing of the bars exceeds or equals 75mm (Fig . On the other hand IS 13920-1993, requires a cross tie when the column bar spacing is equal to or greater than 300mm. ACI 318-02 is also more on the lines of IS 13920 than IS 456 which I feel is unduly punitive. One would expect IS 456 to be less stringent than IS 13920.
If others feel alike, I thought we could, as a group of structural engineers, make a representation to BIS to issue an amendment to IS 456 correcting this requirement for cross ties in columns. I suggest that if there are enough emails regarding this we could send all of them to BIS. May I request those who want to comment on this issue on SEFI to also append their details re. address, co etc. in their emails.
Regards, Alpa Sheth Vakil Mehta Sheth Consulting Engineers 312 Apeejay House 130 B S Marg Mumbai 400 023
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skjain.iitk General Sponsor
Joined: 26 Jan 2003 Posts: 104
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Posted: Fri Feb 20, 2004 12:42 pm Post subject: Column Rings |
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Indeed, it will be a good idea to bring the clause of IS:456 to be in line with that in IS:13920.
Sudhir Jain Professor Civil Engg Dept IIT Kanpur
On Fri, 20 Feb 2004 gyan_th@hotmail.com wrote:
Quote: | Deal All,
I agree with Miss Seth's idea that one expects IS-456 to be less stringent than IS-13920.
Gyaneshwar Th. Sr. Project Executive, NBCC Ltd.
From: alpa_sheth@vakilmehtasheth.com Reply-To: general@sefindia.org To: gyan_th@hotmail.com Subject: Column Rings Date: Thu Feb 19 18:56:17 2004
Dear All,
I was wondering how others are dealing with the dichotomy on the column ring requirements of IS 456 and IS 13920 For Column rings, IS 456-2000 insists that a cross tie is required for column bars when the spacing of the bars exceeds or equals 75mm (Fig . On the other hand IS 13920-1993, requires a cross tie when the column bar spacing is equal to or greater than 300mm. ACI 318-02 is also more on the lines of IS 13920 than IS 456 which I feel is unduly punitive. One would expect IS 456 to be less stringent than IS 13920.
If others feel alike, I thought we could, as a group of structural engineers, make a representation to BIS to issue an amendment to IS 456 correcting this requirement for cross ties in columns. I suggest that if there are enough emails regarding this we could send all of them to BIS. May I request those who want to comment on this issue on SEFI to also append their details re. address, co etc. in their emails.
Regards, Alpa Sheth Vakil Mehta Sheth Consulting Engineers 312 Apeejay House 130 B S Marg Mumbai 400 023
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-------------------------------------------------------------------------- Sudhir K. Jain Professor Department of Civil Engineering Indian Institute of Technology Kanpur Kanpur 208 016, India
Phone: 91-512-2597867 (off), 2598367/ 2590583(home) Fax: 91-512-2597866 (preferred), 2597395 email: skjain@iitk.ac.in ---------------------------------------------------------------------------
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mc.upadhyay1 ...
Joined: 26 Jan 2003 Posts: 134
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Posted: Sat Feb 21, 2004 7:33 am Post subject: Column Rings |
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Hello The ties are provided to avoid premature buckling of longitudinal bars. I think IS 456 assumes when a bar is in between two bars such that spacing is less than or equal to 75mm, it is adequately confined hence don't need a tie. But if this spacing is more a tie is needed. Now the question is to define this "more spacing". If 75mm seems to be quite less; 300mm seems to be quite more. I want to know whether any testing of columns has been done, here or abroad to understand this. How these codes (456 & 13920) arrived at these spacings.
Regards
--------------------------------------------------------------------------------------------------------------------------------------------- Mukesh Chandra Upadhyay Senior Design Engineer M.E. (Str. Engg.) B.E. (Civil) J. P. Ventures Ltd. (Consultancy Organisation of Jaiprakash Ind. Ltd.) 64/4, Site 4, Industrial Area, Sahibabad Ghaziabad, U.P. - 201010
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