Pile Bi-Directional Axial Compressive Load Test
(Osterberg Cell Test)

Static pile load test using embedded hydraulic jack (O-Cell) to load the pile bi-directionally from within — eliminating the need for kentledge for very high-capacity piles.

Overview

What is the Pile Bi-Directional Axial Compressive Load Test?

The Bi-Directional Axial Compressive Load Test (O-Cell test) uses sacrificial hydraulic jacks embedded in the pile during construction. When pressurised, the jack pushes the pile above it upward and below downward simultaneously — measuring skin friction and end bearing without external reaction systems.

Conducted as per ASTM D8169, this method is ideal for very large diameter or high-capacity piles (>5000 tonnes) where conventional kentledge tests are impractical. Global Lab conducts bi-directional load tests with automated data acquisition and equivalent top-load curve construction.

No Kentledge Required

Self-reacting system — no external reaction system needed for very high loads.

Very High Capacity

Suitable for piles >5000 tonne capacity — beyond conventional static test limits.

Skin Friction Separation

Separates upper shaft friction from lower shaft friction and end bearing.

Equivalent Top-Load Curve

Bi-directional results converted to equivalent conventional top-load curve.

NABL Certified Reports

All results on NABL-accredited letterhead per ASTM D8169.

Real-Time Telemetry

Automated data acquisition with real-time data streaming to client dashboard.

Test in Action

Pile Bi-Directional Axial Compressive Load Test — Site Images

O-Cell Jack Installed in Pile Cage

Hydraulic Pressure System and Data Logger

Bi-Directional Load-Movement Curve Plotted

Test Procedure

How the Pile Bi-Directional Axial Compressive Load Test is Conducted

1

O-Cell Installation

O-Cell jacks installed at predetermined level in pile cage before concreting.
2

Instrumentation

Telltale rods and strain gauges installed at multiple levels.
3

Hydraulic Pressure Application

Hydraulic pressure applied to O-Cell in increments. Upward and downward movements recorded.
4

Data Acquisition

Automated data logger records all pressure, load and movement data continuously.
5

Equivalent Top-Load Construction

Bi-directional curves converted to equivalent top-load settlement curve. NABL report within 7 days.

Standards & Specifications

Applicable Test Standards

Standard	Title	Scope	Type
ASTM D8169	Standard Test Methods for Deep Foundations Under Bi-Directional Static Axial Compressive Load	Bi-Directional Test	ASTM
ASTM D1143	Standard Test Methods for Deep Foundations Under Static Axial Compressive Load	Reference Method	ASTM
IS 2911 Part 4	Code of Practice for Design and Construction of Pile Foundations — Load Test	Pile Load Test	Indian Standard
ASCE 20-96	Standard Guidelines for Design and Installation of Pile Foundations	Design Reference	ASCE

Applications

Where is the CAPO Test Used?

Very large diameter bored piles >1500mm for bridge foundations

High-capacity piles for nuclear power plant and industrial structures

Offshore pile testing where conventional reaction systems are impractical

Urban infrastructure piles where space constraints prevent kentledge setup

Research piles for calibration of soil-structure interaction models

Piles in very deep water or inaccessible locations

Why Choose Global Lab

Our Advantages

NABL Accredited ReportsGovernment-accepted certificates for NHAI, PWD and all statutory bodies.

Highest Capacity TestingBi-directional method tests piles beyond 10,000 tonne capacity if needed.

Autovity Real-Time DataLive data streaming and client dashboard access during test.

Skin Friction ProfileLoad distribution at each strain gauge level — complete pile characterisation.

Pan-India CoverageFoundation testing teams across all 7 lab locations.

Combined TestingBi-directional + PDA + PIT offered as a complete foundation assessment.

Pile Bi-Directional Axial Compressive Load Test(Osterberg Cell Test)