SPT Based Pile Capacity Calculator as per IS 2911-2010

Advanced SPT Based Pile Capacity Calculator

Developed By:
Mohan Dangi (Gold Medalist)
Geotechnical Engineer

This calculator estimates pile capacity using IS 2911 SPT correlations.

Input Parameters

Soil Type Cohesionless Soil Non-Plastic Silt / Very Fine Sand Average N Value at Pile Tip (N) Average N Value Along Shaft (N̅) Pile Diameter, D (m) Total Embedded Length of Pile, L (m)

Results will appear here.

Design Formulas

Parameter	Formula
Pile Tip Area (Ap)	Ap = πD² / 4
Shaft Surface Area (As)	As = πDL
Ultimate Capacity for Cohesionless Soil	Qu = 13N(L/D)Ap + (N̅As / 0.50)
Ultimate Capacity for Non-Plastic Silt / Very Fine Sand	Qu = 10N(L/D)Ap + (N̅As / 0.60)
Safe Load Capacity	Qsafe = Qu / 2.5

Explanation:

• Pile tip area is automatically calculated using circular pile geometry.
• Shaft surface area is calculated based on pile circumference and embedded length.
• End-bearing resistance and shaft resistance are calculated separately.
• Ultimate pile capacity is obtained by adding end bearing and skin friction resistance.
• Safe load capacity is calculated using factor of safety = 2.5.
• End-bearing resistance is limited as per IS 2911 recommendation.

Reference:

IS 2911 (Part 1/Sec 2): 2010
Design and Construction of Pile Foundations – Bored Cast In-Situ Piles

Section B-4: Use of Standard Penetration Test Data for Cohesionless Soil

Disclaimer:

This calculator is intended for preliminary estimation and educational purposes only. Actual design should be performed using detailed geotechnical investigation, load testing, and professional engineering judgment.

© Mohan Dangi | Digitech Education