STRUCTURAL ENGINEERING FORUM OF INDIA [SEFI]

mohd_arastu · Posted: Mon Sep 23, 2013 1:20 pm Post subject: HOW TO CALCULATE NUMBER OF PILES

DEAR SEFIEANS

PLEASE GUIDE ME...HOW TO CALCULATE THE NUMBER OF PILES.

I HAVE PILE CAPACITY AS FOLLOWS

1. HORIZONTAL CAPACITY = 44KN
2. COMPRESSION CAPACITY = 280KN
3. UPLIFT/TENSION CAPACITY = 175KN

I HAVE REACTION AT EACH NODE FROM STAAD FOR 17 DIFFERENT LOAD CASES IN THE FORM OF:

FY, FX, FZ, MX, MY, MZ

pravin_shirsath · ... Joined: 23 Jan 2011 Posts: 66

no of piles are depends upon lateral load as well as Vetical load.

1) lateral load = sqrt(fx² + fz²)

no of piles = lateral load/lateral capacity

2) Vertical load increased by approximate 20% for moments

no of piles =Vertical load /vertical capacity

Hence no of piles max of (1) & (2)

mohd_arastu · Posted: Tue Sep 24, 2013 1:21 pm Post subject:

Thanks Mr. Pravin

in case of uplift?

should Self weight of pile cap added to Fy? if yes then how much percentage of Fy?

pravin_shirsath · ... Joined: 23 Jan 2011 Posts: 66

most of time uplift not governing,unless transmission tower (slender structures).

20% is ok as pile cap weight will be marginal comapre to total weight.

most of time lateral capacity & vertical loads governs.

Siva Agathamudi · SEFI Member Joined: 09 Jun 2016 Posts: 10

Dear Mr.Shirsath,

How to find the number of piles with biaxial moment and vertical capacity.
How should i convert the moments into axial force...

Regards,
Siva

es_jayakumar · Posted: Fri Nov 17, 2017 1:08 am Post subject:

You may please refer the book "Reinforced Concrete Vol-I" by H.J.Shah (Charotar), to clarify your query.

E S Jayakumar