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Tension with Bending for pile

 
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wproy
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Joined: 30 Oct 2013
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Location: Kolkata

PostPosted: Sat Feb 07, 2015 12:08 pm    Post subject: Tension with Bending for pile Reply with quote

I am designing pile foundations for Junction house in Steel Plant. I am having a case for the pile to be designed with bending under tension in IS code. But SP-16 and IS456 does not support such case. Any method that can be used in this case ?

The pile is end bearing and 600 dia circular pile
Compressive capacity 120T
Tensile Capacity 60T
Maximum horizontal force in group 3.2T
Length of Fixity 3.77m
Length above ground level 0m
Moment reduction factor 0.82
Pile head is fixed

Moment  in Pile = 9.9 Tm (appx.)
Max uplift in pile = 40 T

Please advice.

Regards,
WP
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spsvasan
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PostPosted: Mon Feb 09, 2015 12:17 am    Post subject: Re: Tension with Bending for pile Reply with quote

Hello Er.Roy,

The book " A Manual of Limit State Design" by Varyani and Radhaji contains some charts for circular sections under tension and BM

With best wishes
S.P.Srinivasan



Wriddhi Pratim Roy wrote:
I am designing pile foundations for Junction house in Steel Plant. I am having a case for the pile to be designed with bending under tension in IS code. But SP-16 and IS456 does not support such case. Any method that can be used in this case ?

The pile is end bearing and 600 dia circular pile
Compressive capacity 120T
Tensile Capacity 60T
Maximum horizontal force in group 3.2T
Length of Fixity 3.77m
Length above ground level 0m
Moment reduction factor 0.82
Pile head is fixed

Moment  in Pile = 9.9 Tm (appx.)
Max uplift in pile = 40 T

Please advice.

Regards,
WP
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abhy_vivek
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PostPosted: Mon Feb 09, 2015 10:33 am    Post subject: Re: Tension with Bending for pile Reply with quote

Dear Er. WP Roy,


     If possible recheck the Loading and the Analysis. Such a high Tension Load in piles may not be recommended / advisable. I would also like to suggest whether the configuration of piles is correct and it can be rearranged to reduce the tensile force.


Regards
Vivek Abhyankar
Mumbai

Wriddhi Pratim Roy wrote:
I am designing pile foundations for Junction house in Steel Plant. I am having a case for the pile to be designed with bending under tension in IS code. But SP-16 and IS456 does not support such case. Any method that can be used in this case ? . . . .

WP
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wproy
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PostPosted: Mon Feb 09, 2015 10:54 am    Post subject: Reply with quote

Thanks for the advice Mr. Srinivasan.

Mr. Abhyankar,
Yes, Tension is coming that much, as it is a piled raft where the 3 columns are positioned in an  'L' shape, so some piles are loaded with uplift of such magnitude. I have found charts in BS code for tension in bending for circular section, but the charts do not come in our d'/d ratio range(i.e. from 0.5 to 2).  

Wriddhi.
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abhy_vivek
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PostPosted: Mon Feb 09, 2015 12:01 pm    Post subject: Reply with quote

Dear Er. Wriddhi,

    As mentioned by you its a Piled-Raft, so how much proportion of Vertical load is shared by Raft vs Piles ? Can you share (because the value you mentioned in last post itself was high, so I am unable to get a FEEL of this structure and it foundation behaviour.

    I am inclined to suggest use of Prestressed Anchors instead for the tension caused due to 'Uplift'. Please correct me if I am wrong or post some photos / drawings to know more about your problem.

    Reg. Tension + Bending - checked Reynold / Mark Fintel's handbook ?

Best Wishes
Vivek Abhyankar

Wriddhi Pratim Roy wrote:
Thanks for the advice Mr. Srinivasan.

Mr. Abhyankar,
Yes, Tension is coming that much, as it is a piled raft where the 3 columns are positioned in an  'L' shape, so some piles are loaded with uplift of such magnitude. I have found charts in BS code for tension in bending for circular section, but the charts do not come in our d'/d ratio range(i.e. from 0.5 to 2).  

Wriddhi.
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wproy
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Location: Kolkata

PostPosted: Wed Feb 18, 2015 11:46 am    Post subject: Reply with quote

Dear Mr. Abhyankar,

I am sorry for my delayed response. Well in this case, a pre-stressed anchoring is a good solution but it is difficult to replicate the same on site. (Confidentiality regretted)

I have checked and found couple of other solutions. Reynolds handbook does have couple of charts for circular sections with uplift and bending.

The formulations required for arriving the chart values are well explained in the book written by P.C. Vargheee.
The coordinates can be arrived by the formula

&


Thanks for the advices.

Regards,
Wriddhi.
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ind_mr
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Joined: 14 Nov 2017
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PostPosted: Tue Nov 14, 2017 7:06 am    Post subject: Reply with quote

Hi Wriddhi,
which is the BS code with design charts for tension and bending for circular section???



wproy wrote:
Thanks for the advice Mr. Srinivasan.

Mr. Abhyankar,
Yes, Tension is coming that much, as it is a piled raft where the 3 columns are positioned in an  'L' shape, so some piles are loaded with uplift of such magnitude. I have found charts in BS code for tension in bending for circular section, but the charts do not come in our d'/d ratio range(i.e. from 0.5 to 2).  

Wriddhi.
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