IS 2911:1979 is the Indian Standard (BIS) for design and construction of pile foundations. This code sets forth the guidelines for the design, construction, and testing of various types of pile foundations. It details the methods to calculate load-carrying capacities statically, dictates spacing and group action rules, and outlines testing procedures like initial and routine pile load tests.
Provides methods for design and construction of pile foundations, including guidance on site investigation and boring practices, often referenced for its investigation aspects.
Quick Reference — IS 2911:1979 Pile Foundation (legacy)
Older umbrella code for design and construction of pile foundations. Now replaced by part-wise IS 2911:2010+.
| Reference | Value | Clause |
|---|
| Pile types covered — driven precast | Section 1 | Section 1 |
| Pile types covered — driven cast-in-situ | Section 2 | Section 2 |
| Pile types covered — bored cast-in-situ | Section 3 | Section 3 |
| Pile types covered — under-reamed | Section 4 (also IS 2911 Pt 3) | Section 4 |
| Minimum centre-to-centre spacing — friction piles | 3 × diameter | Cl. 5.5.1 |
| Minimum spacing — end-bearing piles | 2.5 × diameter | Cl. 5.5.1 |
| Minimum cover — pile cap to ground | 75 mm above NGL | Cl. 5.6.2 |
| Minimum reinforcement — driven precast | 1.25 % of cross-section | Cl. 5.10.1 (Sec 1) |
| Minimum reinforcement — bored cast-in-situ | 0.4 % of cross-section | Cl. 5.10.1 (Sec 3) |
| Minimum concrete grade — bored CIS | M25 | Cl. 5.4 (Sec 3) |
| Minimum concrete grade — driven precast | M30 | Cl. 5.4 (Sec 1) |
| Slump for tremie concreting (bored) | 150–200 mm | Cl. 6.5 (Sec 3) |
| Maximum allowable verticality deviation | 1 in 50 (driven), 1 in 100 (bored) | Cl. 6.7 |
| Position tolerance (pile head) | 75 mm | Cl. 6.7 |
| Group efficiency — friction pile group | = 1 − (θ/90) × ((n−1)m + (m−1)n) / (90 m n) | Cl. 5.5.4 (Converse-Labarre) |
| Allowable settlement — pile group | ≤ 25 mm (or per IS 1904) | Cl. 5.13 |
| Initial load test — load magnitude | 2.5 × design load | Cl. 8.1 (refers IS 2911 Pt 4) |
| Routine load test — load magnitude | 1.5 × design load | Cl. 8.2 (refers IS 2911 Pt 4) |
| Number of test piles — initial | 0.5 % of total piles (min 2) | Cl. 8.1 |
| Lateral load — typical limit | 12 mm at design lateral load | Cl. 5.13.2 |
⚠ Superseded by part-wise IS 2911 (Part 1 Sec 1, 2, 3, 4 — driven, bored, under-reamed; Part 4 — load test). 1979 edition still cited for design philosophy and historical comparison.
Overview
- Status
- Superseded — superseded by IS 2911 (Parts 1 to 4):2010
- Usage level
- Essential
- Domain
- Geotechnical — Surveying and Geotechnical Investigation
- Type
- Code of Practice
- Amendments
- Amendment 1 (1984)
Also on InfraLens for IS 2911
Practical Notes
! The 1979 version has been superseded by the 2010 version, which increased the minimum grade of concrete for cast-in-situ piles from M20 to M25.
! Always perform a pile load test to validate the static formula calculations, as soil characteristics vary significantly.
! Ensure proper execution of tremie concreting in bored cast-in-situ piles to prevent soil inclusion and necking.
Frequently referenced clauses
Updates & Amendments1 amendment
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
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International Equivalents
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International Comparison — Coming Soon
We're adding equivalent international standards for this code.
Key Values6
Quick Reference Values
minimum spacing friction piles3 times pile diameter
minimum spacing end bearing piles2.5 times pile diameter
minimum spacing piles resting on rock2 times pile diameter
factor of safety static capacity2.5
maximum settlement routine test12 mm
maximum settlement initial test10% of pile diameter (for bored piles)
Key Formulas
Qu = Ap * Nc * Cp + As * α * C — Ultimate static bearing capacity in cohesive soils
Eg = Qg / (n * Q1) — Group efficiency of piles
Tables & Referenced Sections
Key Tables
Table for Bearing Capacity Factors (Nc, Nq, Nγ)
Table for Adhesion Factor (α) in Cohesive Soils
Table for Modulus of Subgrade Reaction
Key Clauses
Spacing of Piles
Bearing Capacity of Piles (Static Formula)
Group Action of Piles
Structural Design of Piles
Pile Load Testing Methods
Frequently Asked Questions4
What is the minimum spacing required between friction piles?+
The minimum center-to-center spacing should be 3 times the shaft diameter.
What is the minimum spacing for piles resting on hard stratum?+
The minimum center-to-center spacing is 2.5 times the diameter, which can be reduced to 2 times for piles resting on rock.
What factor of safety is generally used for determining the safe load from static formulas?+
A minimum factor of safety of 2.5 is normally adopted.
What defines the safe load in a routine pile load test?+
The load corresponding to a maximum settlement of 12 mm.
QA/QC Inspection Templates
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QA/QC templates coming soon for this code.