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IS 2911 Part 1/Section 2 : 2010Design and Construction of Pile Foundations - Concrete Piles (Bored Cast-in-situ Concrete Piles)

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EN 1997-1 · BS 8004 · ACI 336.3R
CurrentFrequently UsedCode of PracticeBIMGeotechnical · Coastal and Marine Engineering
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OverviewValues6InternationalTablesFAQ4RelatedQA/QCNew

IS 2911:2010 Part 1/Section 2 is the Indian Standard (BIS) for design and construction of pile foundations - concrete piles (bored cast-in-situ concrete piles). This part of IS 2911 covers the design, construction, and installation of bored cast-in-situ under-reamed piles. It is particularly crucial for designing foundations in expansive soils like black cotton soil to prevent uplift and settlement, and is widely used for transmission towers and lightly loaded structures.

Specifies design and construction procedures for bored cast-in-situ concrete piles.

Overview

Status
Current
Usage level
Frequently Used
Domain
Geotechnical — Coastal and Marine Engineering
Type
Code of Practice
Amendments
Amendment 1 (2014)
International equivalents
EN 1997-1:2004 + EN 1536:2010 · European Committee for Standardization (CEN), EuropeBS 8004:2015+A1:2020 · British Standards Institution (BSI), United KingdomACI 336.3R-14 · American Concrete Institute (ACI), USAAS 2159:2009 · Standards Australia, Australia
Typically used with
IS 456IS 1080IS 1498IS 1892IS 2131
Also on InfraLens for IS 2911
6Key values2Tables4QA/QC templates1Handbook topics1Knowledge articles4FAQs

BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.

Practical Notes
! Under-reamed piles are highly effective in expansive soils to counteract heave due to moisture changes.
! Ensure proper cleaning of the borehole base and under-reamed bulbs using a bucket auger before placing concrete.
! If high groundwater table is encountered, concrete must be placed using a tremie pipe to prevent cement wash-out and segregation.
Frequently referenced clauses
Cl. 5MaterialsCl. 6.2Spacing of PilesCl. 6.3Bearing CapacityCl. 7Structural DesignCl. 8Construction
Pulled from IS 2911:2010. Browse the full clause & table index below in Tables & Referenced Sections.
Updates & Amendments1 amendment
2014Amendment 1 (2014)
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
concretesteelbentonite slurrysoil

International Equivalents

Similar International Standards
EN 1997-1:2004 + EN 1536:2010European Committee for Standardization (CEN), Europe
HighCurrent
Eurocode 7: Geotechnical design - Part 1: General rules & EN 1536: Execution of special geotechnical works - Bored piles
EN 1997-1 covers design principles while EN 1536 covers execution, together matching the IS code's scope.
BS 8004:2015+A1:2020British Standards Institution (BSI), United Kingdom
HighCurrent
Code of practice for foundations
Provides comprehensive guidance on the design and construction of all pile types, including bored cast-in-situ.
ACI 336.3R-14American Concrete Institute (ACI), USA
HighCurrent
Report on Design and Construction of Drilled Piers
Directly addresses the design and construction of drilled piers, the US term for bored cast-in-situ piles.
AS 2159:2009Standards Australia, Australia
MediumCurrent
Piling - Design and installation
Covers the entire piling process, with significant overlap on design and installation of bored piles.
Key Differences
≠IS 2911 primarily uses a working stress design (WSD) approach with a single global factor of safety (typically 2.5), whereas Eurocode 7 and other modern standards use a Limit State Design (LSD) approach with separate partial factors on actions (loads) and resistances (ground/material strength).
≠IS 2911 specifies a minimum longitudinal reinforcement of 0.4% of the pile's gross cross-sectional area. In contrast, codes like BS 8004 vary the minimum reinforcement based on design actions (e.g., 0.5% for piles resisting bending, potentially less for pure compression).
≠The criteria for determining safe load from a static load test are explicitly defined in IS 2911 (Part 4), often based on settlement limits (e.g., settlement of 12 mm or 2% of pile diameter). International codes like Eurocode 7 provide a framework for interpretation but allow for various accepted methods (e.g., Chin-Kondner extrapolation, 0.1D method).
≠IS 2911 specifies a relatively narrow concrete slump range of 150-180 mm for tremie concrete. International execution standards like EN 1536 are more flexible, using slump classes (e.g., S4: 160-210 mm) and explicitly accommodating self-compacting concrete (SCC) with flow criteria.
Key Similarities
≈All standards are fundamentally based on the principle that the ultimate pile capacity is the sum of end bearing resistance and skin friction resistance (Qu = Qp + Qs).
≈There is a universal emphasis across all codes on the critical importance of a comprehensive geotechnical investigation as the basis for a safe and economical pile foundation design.
≈The descriptions of construction methodologies are highly consistent, including the sequence of boring, use of temporary casing or stabilizing fluids (bentonite/polymer), placement of reinforcement cages, and concreting from the bottom up using a tremie pipe to ensure concrete integrity.
≈All modern standards, including IS 2911, recommend or mandate non-destructive integrity testing (e.g., low-strain sonic integrity, cross-hole sonic logging) to verify the as-built quality of the piles and check for defects.
Parameter Comparison
ParameterIS ValueInternationalSource
Design Safety ApproachWorking Stress Design with global Factor of Safety (typically 2.5 on ultimate load).Limit State Design with partial factors on loads and resistances (e.g., γ_R = 1.4 for end bearing).EN 1997-1
Minimum Concrete Cover (to main bars)60 mm75 mm (for piles cast directly against soil)BS 8004:2015
Minimum Centre-to-Centre Pile Spacing3 x Pile Diameter3 x Pile Diameter is a commonly recommended minimum spacing.ACI 336.3R-14
Concrete Slump (for tremie placement)150 mm to 180 mmTypically Class S4 (160 mm to 210 mm) or higher workability classes.EN 1536:2010
Minimum Longitudinal Reinforcement0.4% of gross cross-sectional area0.5% for piles resisting bending moments.BS 8004:2015
Positional Tolerance (at cut-off level)75 mm in any direction.75 mm for single piles or piles in a two-pile group.EN 1536:2010
Cut-off Level Tolerance (vertical)+25 mm / -75 mm± 50 mmEN 1536:2010
⚠ Verify details from original standards before use

Key Values6

Quick Reference Values
ratio of under ream to shaft diameter2 to 3 (usually 2.5)
minimum spacing between piles2 times under-ream diameter (2Du)
minimum grade of concreteM 20
minimum longitudinal reinforcement0.4 percent of the gross cross-sectional area of the pile shaft
minimum clear cover to longitudinal reinforcement40 mm
vertical spacing between two under reams1.25 to 1.5 times the under-ream diameter
Key Formulas
Qu = Ap * Nc * cp + α * c * As + ... (Static formula for ultimate bearing capacity of under-reamed pile in clay)
Safe Load = Ultimate Bearing Capacity / Factor of Safety (Usually 2.5)

Tables & Referenced Sections

Key Tables
Table 1 - Safe Load for Vertical Bored Cast in Situ Under-Reamed Piles in Cohesive Soils
Table 2 - Safe Load for Vertical Bored Cast in Situ Under-Reamed Piles in Sandy Soils
Key Clauses
Clause 5 - Materials
Clause 6.2 - Spacing of Piles
Clause 6.3 - Bearing Capacity
Clause 7 - Structural Design
Clause 8 - Construction

Related Resources on InfraLens

Cross-Referenced Codes
IS 456:2000Plain and Reinforced Concrete - Code of Pract...
→
IS 1080:1985Code of Practice For Design And Construction ...
→
IS 1498:1970Classification and identification of soils fo...
→
IS 1892:1979Code of practice for site investigations for ...
→
IS 2131:1981Method for standard penetration test for soil...
→
Handbook & Design Rules
Handbook Topics
📖Pile Bearing Capacity (IS 2911)
→
Articles & Guides
📖Foundation Selection Guide — Isolated, Combined, Raft, Pile
→

Frequently Asked Questions4

What is the standard ratio of under-ream diameter to shaft diameter?+
The ratio is normally 2 to 3, but generally a value of 2.5 is used in practice.
What is the minimum spacing allowed between two under-reamed piles?+
The minimum spacing should be 2 times the under-ream diameter (2Du).
What is the minimum longitudinal reinforcement required for an under-reamed pile?+
Minimum 0.4 percent of the gross cross-sectional area of the pile shaft.
How many bulbs can an under-reamed pile have?+
They can be single or multi-under-reamed (typically up to two or three bulbs) depending on load requirements and soil strata.

QA/QC Inspection Templates

Code-Specific Templates for IS 2911
📝
Piling Method Statement
form
Excel / PDF
📐
Geotechnical ITP
plan
Excel / PDF
📋
Pile Driving / Boring Log
register
Excel / PDF
📝
Piling Method Statement
form
Excel / PDF