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Column Rings

 
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alpa_sheth
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Joined: 26 Jan 2003
Posts: 281

PostPosted: Thu Feb 19, 2004 1:26 pm    Post subject: Column Rings Reply with quote

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 Cool. 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
SEFI Member


Joined: 26 Jan 2003
Posts: 9

PostPosted: Thu Feb 19, 2004 3:05 pm    Post subject: Column Rings Reply with quote

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 Cool. 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
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Joined: 26 Jan 2003
Posts: 192

PostPosted: Fri Feb 20, 2004 4:48 am    Post subject: Column Rings Reply with quote

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 Cool. 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
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Joined: 26 Jan 2003
Posts: 192

PostPosted: Fri Feb 20, 2004 4:48 am    Post subject: Column Rings Reply with quote

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 Cool. 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
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Joined: 26 Jan 2003
Posts: 192

PostPosted: Fri Feb 20, 2004 5:30 am    Post subject: COLUMN RINGS Reply with quote

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
SEFI Regulars


Joined: 26 Jan 2003
Posts: 20

PostPosted: Fri Feb 20, 2004 7:21 am    Post subject: Column Rings Reply with quote

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
Progressive Member


Joined: 26 Jan 2003
Posts: 40

PostPosted: Fri Feb 20, 2004 12:32 pm    Post subject: Column Rings Reply with 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.

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 Cool. 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
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Joined: 26 Jan 2003
Posts: 104

PostPosted: Fri Feb 20, 2004 12:42 pm    Post subject: Column Rings Reply with quote

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 Cool. 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
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Joined: 26 Jan 2003
Posts: 134

PostPosted: Sat Feb 21, 2004 7:33 am    Post subject: Column Rings Reply with quote

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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