The Use and Construction of Drilled Shaft FoundationsPrepared By:

ADSC Northeast ChapterA Regional Chapter of the ADSC

The International Association of Foundation Drilling

In Cooperation With:

ADSC:The International Association of Foundation Drilling

8445 Freeport Parkway Suite 325· Irving, TX 75063Telephone: (469) 359-6000 · Fax: (469) 369-6007

E-mail: adsc@adsc-iafd.com

THE HISTORY AND OBJECTIVES OF THE ADSC

The Association was founded in 1964 and is comprised of foundation drilling, anchored earth retention and geo-support contractors (Contractor Members), manufacturers and suppliers to the industries (Associate Members), andengineering and design professionals (Technical Affiliate Members), and students enrolled in construction and/orengineering related programs.

The work of the ADSC…

1) Establish Standards and Specifications for the Foundation Drilling, Anchored Earth Retention and Geo-Support Industries

2) Conduct Design, Construction and Inspection Seminars worldwide3) Hold Meetings4) Fund and conduct original research5) Promote ethical practices6) Develop technical materials7) Serve as clearing house for information8) Provide educational scholarships9) Interface with corresponding industries10) Establish international labor-management agreements11) Provide a forum for the free flow of ideas12) Stimulate industry growth13) Government liaison task force

THE HISTORY AND OBJECTIVES OF THE ADSC

The ADSC’s publications include:

FOUNDATION DRILLING Magazine, published eight times per year, is a colorfulmagazine dealing with the latest developments in the foundation drilling, anchoredearth retention and geo-support industries. Subscriptions are available. Contact theADSC International office for fees and further information.

The ADSC has published a complete Technical Library Catalog available free uponrequest from the ADSC office. It contains a description of all technical materialsavailable, plus management aids, films, videos, slide presentations, and books.

ADSC: The International Association of Foundation Drilling is a trade associationcomprised of people working together to advance all aspects of the industries it serves.To learn more about how you can become a Contractor, Associate, or TechnicalAffiliate Member of the ADSC, please contact our International Office or any member.

Design for Constructibility

•Engineering design cannot be separated from the construction of drilled shafts.

•Construction methods and materials will influence the capacity, load-displacement characteristics, and economics of drilled shafts.

Definition of Drilled Shaft Foundation

(Drilled Pier, Bored Pile, Cast-In-Drilled-Hole, Drilled Caisson, etc.)

1) Excavate a cylindrical hole in the ground.

2) Fill excavation with concrete, usuallyreinforced.

Advantages of Drilled Shafts

When properly designed and constructed:

1).Reliability

3).Versatility

2).Economy

SOIL EXTRACTEDON OPEN-FLIGHTAUGER.

SINGLE DRILLED SHAFT FOUNDATION

TRANSMISSION LINE PROJECT

SHORINGSYSTEMS

HIGH-RISEPROJECT

BRIDGE STRUCTURE OVER WATER

OFFSHORE DRILLING

HILLSIDE DRILLING

SEISMICRETROFITBUILDING

SEISMICRETROFITBRIDGE / VIADUCT

RESIDENTIAL

BATTEREDPILE FOUNDATIONS

PERMANENTRETAININGWALLS

DEEPBASEMENTEXCAVATIONS

TUNNEL ACCESS SHAFT

Construction of Drilled Shafts

•Construction Methods

•Construction Equipment

•Design for Constructibility

DRY METHOD OF CONSTRUCTION

OPEN HOLEEXCAVATION

SLURRY METHOD OF CONSTRUCTION

SLURRYDISPLACEMENTMETHOD

PROPERTIESOF SLURRY

Functions of Slurry

1) Maintain the stability of the excavation

2) Prevent suspended particles from settling out

3) Allow clean displacement by concrete

4) Allow easy pumping

SUGGESTED SPECIFICATIONSFOR BENTONITE SLURRY (1)

Property Range @ 20º C Test Method

Density less than 1.10 g/ml mud density balance

Viscosity 30 to 90 seconds Marshal funnelless than 20 cP Fann viscometer

Shear Strength 4 to 40 N/m2 shearometer1.4 to 10 N/m2 Fann viscometer

PH 9.5 to 12 pH indicatorpaper strips

(1) FEDERATION OF PILING SPECIALISTS

MUD DENSITY BALANCE

MARSH FUNNEL

FANN VISCOMETER

SHEAROMETER

LITMUS TEST (pH)

SLURRYPROCESSING PLANT

CASING METHOD OF CONSTRUCTION

TELESCOPINGCASING

Construction of Drilled Shafts

• Construction Methods

• Construction Equipment

• Design for Constructibility

DRILL RIGS

Kelly Bar

Power Unit

RotaryTable

CRANE MOUNTED ATTACHMENT

TEXOMA 600 (TRUCK-MOUNTED)

TRUCKMOUNTEDDRILLING UNITS

“BIG STAN”

TOP-DRIVEDRILLING UNITS

LONG REACHDRILLING UNITS

CRANE MOUNT

CASINGOSCILATOR

CASING ROTATOR

LOW OVERHEAD DRILLING

DRILL TOOLING

AUGERS

AUGERS

ROCK AUGER

DOUBLE-FLIGHTED AUGER

BOULDER ROOTER -“CHRISTMAS TREE” AUGER

DIGGING BUCKETS

BELLING BUCKETS

CORE BARRELS

AIR CIRCULATIONCORE BARRELS

ROCK CORING

CLUSTER DRILL

DOWN-THE-HOLE HAMMER

CHURN BIT

TRI-CONE ROLLER BIT

GRABBUCKETS

INSTALLATIONOF

TEMPORARY CASING

CASING TWISTER

STARTER CASING

TELESCOPINGCASING

SLEDGE &POWER SWIVEL

TOP DRIVE

CASING OSCILATORWITH GRAB BUCKET

VIBRATORY HAMMERS

CLEANING-OUTTHE BOTTOM

OF THE DRILLED SHAFT

CLEAN-OUTBUCKETS

HYDRAULIC PUMP

AIR LIFT -“PORTUGUESE PUMP”

HAND -CLEANING

INSTALLATIONOF REINFORCING

STEEL CAGE

REBAR CAGEFABRICATION

REBAR CAGEINSTALLATION

LIFTING OF LONG REBAR CAGE

REBAR CAGEPOSITIONINGDURINGCONCRETEPOUR

FINALPOSITIONINGOF REINFORCING CAGE

Concrete Placement: Key Factors

• Concrete should be placed as soon as possible after the hole is completed

• The concrete should have good flow characteristics

• The concrete placement techniques must result in complete filling of the excavation without segregation

FREE-FALL METHODS

CONCRETEBOOM-PUMP

TREMIE POUR

FINISHEDCUT-OFF

Construction of Drilled Shafts

• Construction Methods

• Construction Equipment

• Design for Constructibility

Design for Constructibility

Remember:

“Do Not Design on Paper WhatYou Have to Wish into the Ground”

- KARL TERZAGHI

Design for Constructibility: The Keys

• Subsurface Investigation

• Appropriate Concrete Design

• Appropriate Steel Design and Tolerances

• Inspection

CIRCA 1920’s

This presentation has been prepared specifically for use by the Association of Drilled Shaft Contractors West Coast

Chapter and the International Association of Foundation Drilling.

Duplication, modification, or use of this presentation by others, is strictly

prohibited without the expressed written permission by the Association of Drilled Shaft Contractors or the International

Association of Foundation Drilling.