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pravin_shirsath ...

Joined: 23 Jan 2011 Posts: 66
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Posted: Wed Dec 17, 2014 8:33 am Post subject: BATTEN PLATE SPACING |
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I have to give batten plate spacing for channel placed back to back.
channels are braced & without braced effective length changes.
as per IS 800 clause 7.7.3
spacing = 0.7times slendeness ratio of member.
for braced column slenderness ratio is less compared to unbrace column.
so spacing required for braced column is less compare to unbraced column.
Can you please see attached file?
please comment.
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abhy_vivek Silver Sponsor


Joined: 26 Jan 2003 Posts: 690
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Posted: Thu Dec 18, 2014 9:17 am Post subject: Re: BATTEN PLATE SPACING |
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Pravin I think there is some confused made amongst - words Lacing / Bracing and battening ?
what is your exact question is also not clear, so no one has yet replied to your query.
pravin_shirsath wrote: | I have to give batten plate spacing for channel placed back to back.
channels are braced & without braced effective length changes.
as per IS 800 clause 7.7.3
spacing = 0.7times slendeness ratio of member.
for braced column slenderness ratio is less compared to unbrace column.
so spacing required for braced column is less compare to unbraced column.
Can you please see attached file?
please comment. |
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pravin_shirsath ...

Joined: 23 Jan 2011 Posts: 66
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Posted: Thu Dec 18, 2014 9:59 am Post subject: |
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column back to back channel sections are same for Frame 1 & Frame 2
1) Frame 1 :
colums are placed back to back channels (open section) and columns are braced by tube for framing(connected at web).
my question is if i have to give batten at flanges,
Effective length is less than frame 2 due to bracing.
hence for braced frame,spacing requirement is less due to slenderness ratio & due to IS 800 clause.
2) Frame 2 :
Effective length is more compare to frame 1.
hence unbraced frame (without tube) slenderness ratio is more , so spacing required is more.
I am little confused with Clause for braced column (frame 1) ,batten spacing requiement is less compare to unbrace column (frame 2)?
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Dr. N. Subramanian General Sponsor


Joined: 21 Feb 2008 Posts: 5553 Location: Gaithersburg, MD, U.S.A.
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Posted: Fri Dec 19, 2014 2:46 am Post subject: |
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Dear Er Pravin,
First of all the column shown by you is a laced column and not a battened column.
You must check local as well as overall buckling. For laced column the length to be taken is 1.05L.
The system shown by you is not efficient. You need to keep rxx and ryy more or less same. Moreover welding of the tube in between the channels may give practical difficulties.
Best wishes
NS
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pravin_shirsath ...

Joined: 23 Jan 2011 Posts: 66
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Posted: Sat Dec 20, 2014 9:10 am Post subject: |
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Thank you NS sir for your reply.
I am planning bolting between column web & tube.
as my setion is open i.e. back to back channel with inside lacing ,
what i understand is i do not need batten plate for laced column.
but flanges are open & these sections are cold formed ??
is there any example or any references for such type of cases??
Regards,
Pravin K Shirsath
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abhy_vivek Silver Sponsor


Joined: 26 Jan 2003 Posts: 690
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Posted: Mon Dec 22, 2014 8:06 am Post subject: |
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Pravin, if you do not mid one quick question.
Has your boss or any experienced senior checked this structural configuration, before you post it on Sefi ?
I again, repeat, that this question is not to discourage you or any Young Growing Structural Engineer from asking questions in forum. But just wanted to find out 'Whether the designers / Structural Engineers in India or elsewhere' are learning on their own, by trail and error ?. . . If so then the trend is not good for 'Structures Health'.
Reg
Vivek
pravin_shirsath wrote: | Thank you NS sir for your reply.
I am planning bolting between column web & tube.
as my setion is open i.e. back to back channel with inside lacing ,
what i understand is i do not need batten plate for laced column.
but flanges are open & these sections are cold formed ??
is there any example or any references for such type of cases??
Regards,
Pravin K Shirsath |
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pravin_shirsath ...

Joined: 23 Jan 2011 Posts: 66
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Posted: Tue Dec 23, 2014 8:19 am Post subject: |
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I really concern with your worry about structrual safety. this is some research type of work.
Very good research scientist & structural engineer having age more than 60 years is involved in this type of work.
I am just collecting information for my reference.
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abhy_vivek Silver Sponsor


Joined: 26 Jan 2003 Posts: 690
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Posted: Wed Dec 24, 2014 12:06 pm Post subject: |
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Ok Pravin,
Good to note that you have mentors who are highly experienced (at least in terms of age).
In past couple of months, I came across not less than 10 / 12 designers who are working in
isolation without any guidance / mentor in India, China, Dubai, S. Korea etc. They are struggling
for guidance / literature. Some times refer wrong / superseded references. And somehow complete
the designs.
Industry should do something to face such reality. Otherwise the structures will be in danger.
There are many Big Consulting companies who outsources the work to small companies / individuals
Finally the work suffers.
Reg
Vivek
pravin_shirsath wrote: | I really concern with your worry about structrual safety. this is some research type of work.
Very good research scientist & structural engineer having age more than 60 years is involved in this type of work.
I am just collecting information for my reference. |
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dipak_bhattacharya ...


Joined: 18 Jun 2011 Posts: 76
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Posted: Sun Jan 04, 2015 4:39 pm Post subject: Batten Plate Spacing |
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This is today's scenario in Indian Private Consulting Companies.
Culture is not to spend any money or waste time on any employee engineer. They recruit fresh / inexperienced engineers with pitiable salaries,because supply of engineers passing from private colleges are much more than the requirement of the market.In critical situations only, those private company owners outsource the assignments.
The other side of the story is that those junior engineers always remain on the lookout of jumping from one company to other and quit at the earliest opportunity, only for better money.They can't be retained by any means because the employer has trained them.
So who is to blame whom?And who can help the situation? Companies are struggling to survive.
Experienced engineers are busy and do not find it worthy to waste time on this kind of forums.
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