STRUCTURAL ENGINEERING FORUM OF INDIA [SEFI]

SRAVANTHI · SEFI Member Joined: 28 Jun 2011 Posts: 7

Dear Sefians

Why is the edge distance of pile to pile cap 150mm according IS 2911? What is the criteria for 150mm?

gpsarathyy · ... Joined: 28 Jun 2010 Posts: 487

Dear Sefian,
Minimum edge distance to be maintained between the pile cap and the piles.
In order to provide rebars between the pile and the outer pilecap and considering the cover requirements. It is fixed as 0.15m,(as minimum)
But you can have additional edge distance also.
Based on the case to case it shall be finalised.

N. Prabhakar · General Sponsor Joined: 25 Apr 2009 Posts: 474

Deleted

N. Prabhakar · General Sponsor Joined: 25 Apr 2009 Posts: 474

Dear Sefians,

In small sized pile caps (for and up to 6 piles, not raft type), where the angle θ subtended from centre lines of column to pile (see sketch attached) is geater than 30⁰, then there is tie-strut action in the transfer of load from the column to the pile. In this context, the tie is the reinforcement provided at the bottom between piles, and the strut is the inclined compression zone of concrete from column to pile.

The tie reinforcement is to be anchored well beyond the centre line of pile with a development length. Because the edge projection of concrete beyond pile is normally small, providing the required development length of tie bar beyond centre line of pile is a problem to satisfy the requirement of Cl. 26.2.2.5 of IS 456: 2000 which would involve providing a large radius of bend to reinforcement bar at 90⁰bend. This detailing is not practical in all cases. Alternatively, horizontal links of equivalent area equal to 1/4 area of the main tie bars, are to be provided very close to the bottom tie reinforcement to take care of the bursting action due to tie force. Please see the the attachments.

I trust you will find the above information useful in detailing pile cap reinforcement.

With best wishes,

N. Prabhakar, BE, CEng(I), MIStructE (UK), MIE (Ind)
Chartered Structural Engineer
Vasai (E), Pin 401 208[/quote]

N. Prabhakar · General Sponsor Joined: 25 Apr 2009 Posts: 474

Dear Sefians,

I am attaching a jpg file which is missing in my previous posting.

With best wishes,

N. Prabhakar

N. Prabhakar · General Sponsor Joined: 25 Apr 2009 Posts: 474

Dear Sefians,

I am attaching jpg files which are missing in my previous posting.

With best wishes,

N. Prabhakar

N. Prabhakar · General Sponsor Joined: 25 Apr 2009 Posts: 474

Dear Sefians,

I am attaching docx files which are missing in my previous posting.

With best wishes,

N. Prabhakar

N. Prabhakar · General Sponsor Joined: 25 Apr 2009 Posts: 474

Dear Admin,

Why my attachments in this posting are not seen?

These attachments are important in the context of my text. Please do the needful.

Thanks.

N. Prabhakar

SRAVANTHI · SEFI Member Joined: 28 Jun 2011 Posts: 7

Thank you for your information sir.

es_jayakumar · Posted: Mon Apr 17, 2017 4:17 pmPost subject:

I think, there is one more point in keeping the edge distance of 150mm, from construction point of view. It is difficult to keep the pile centres exactly to the required alignment while casting them. So, this edge distance of 150mm will give us allowance to keep the pile cap and thereby column in the exact location, despite the piles being minutely wayward.

E S Jayakumar