October 12, 2016

DEEP FOUNDATIONS FOR TRANSPORTATION FACILITIES: A HISTORIC PERSPECTIVE

John G. Delphia

TxDOT Bridge Division – Geotechnical Branch Manager

October 12, 2016

TxDOT Foundation Use - Historical Perspective

2

-- Spread footing foundations were used occasionally into the 1970’s to support

bridges in competent soil or rock, but the increasing economy of drilled shafts

resulted in an end to the use of spread footings.

-- Driven piling have been used effectively in softer soils, as they displace the soil

and rely on skin friction.

-- TxDOT has used drilled shafts to found bridges since the late 1940’s. Drilled

shafts can be used in a wide variety of soil/rock conditions. TxDOT is

generally considered to be the largest user of drilled shafts in the United

States.

October 12, 2016

Spread Footing

3

October 12, 2016

TxDOT Deep Foundations

4

DEEP FOUNDATIONS

PILING DRILLED SHAFTS

October 12, 2016

TxDOT Piling – Historical Perspective

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1925 – Concrete Structures -

Substructure Design - “For

streams where erosion is

possible, piling should

preferably be used (if possible

to drive) as a protection against

scour, even though the safe

bearing resistance of the

natural soil is sufficient to

support the substructure

without piling.”

1950 – Timber

Piling, Precast

Concrete Piling, and

Steel H Piling were

included in the

TxDOT

Specifications Book.

1962– Steel Piling

(Steel H and Sheet

Piling) replaced

Steel H Piling. Metal

Shell Piling was

included in the

TxDOT

Specifications Book.

1993– Metal Shell

Piling was removed

from the TxDOT

Specifications Book.

October 12, 2016 6

http://www.vulcanhammer.info/on/differential.php

Pile Driving

~ 1940’s

Pile Driving

~ 1950’s

http://www.vulcanhammer.info/on/photos.php

Pile Driving

~ 1960’s

http://www.vulcanhammer.info/products/leaders.php

October 12, 2016

Piling

7

Diesel Hammer

Hydraulic Hammer

Vibratory

Hammer

October 12, 2016

Piling

8

Timber Piling

Steel Pipe

Piling

Steel H PilingConcrete

Piling

October 12, 2016

TxDOT Drilled Shafts – Historical Perspective

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(From: http://www.ahbeck.com/)

1962 –

Introduction of

slurry into the

TxDOT

Specifications.

1972 –Human

/visual inspection

of the bottom of

the hole is still

required. Belled

Drilled Shafts

being used less.

1950 – Drilled

Shafts included

in the TxDOT

Specifications

and human

inspection of bell

shaped footing.

1932 – Several companies in

Texas first started using

drilled shafts for private jobs.

Pioneering work on drilled shafts was funded by TxDOT beginning in

1968. Dr. Lymon Reese and Dr. Mike O’Neill performed the bulk of

this research at the University of Texas and later the University of

Houston. This research was included in the FHWA Drilled Shaft

Manual.

1993 - TxDOT

Specification was

updated to include

slurry requirements,

underwater placement ,

and no human

examination of the

bottom of the hole.

TxDOT first used drilled shafts to found bridges in the late

1940’s.

October 12, 2016

Drilled Shafts

10

Drilled Shaft Equipment

~ 1950’s

October 12, 2016

Belled Drilled Shafts

11

Reamer for Belled Shaped Drilled Shafts

~ 1950’s

Soil

Rock

October 12, 2016

Drilled Shafts

12

Drilled Shaft Equipment

~ 2005

October 12, 2016

TxDOT Deep Foundations

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DEEP FOUNDATION DESIGN

TEXAS CONE

PENETROMETER

TESTING

DESIGN

CORRELATION

CHARTS

October 12, 2016

Texas Cone Penetrometer History

14

Development of the Texas

Cone Penetrometer (TCP)

Test

1949 – First

use of the TCP

test.1956 – TCP

correlation charts first

published. Drilled

shafts designed for

point bearing. Skin

friction for Piles.

1972– TCP

correlation charts

were updated.

Drilled shafts

designed for skin

friction and point

bearing.

1982 & 2000– TCP

correlation charts

were updated.

October 12, 2016

Texas Cone Penetrometer

15

October 12, 2016

Texas Cone Penetrometer Design Curves

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October 12, 2016

TxDOT Design Method History

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History of TxDOT Design Method

1949 – 1971

- spread footing designed on bearing

- piling designed on skin friction

- drilled shaft designed on point bearing

1972 – Present

- spread footing on rock designed on bearing

- piling designed on skin friction

- drilled shafts designed on combination of

skin friction and point bearing

October 12, 2016

Drilled Shaft Design

18

Soil

Rock

Rock Bearing

Soil

Rock

Soil

Skin

Friction

Rock Skin

Friction

Rock

Bearing

October 12, 2016

Recent Advancements in Deep Foundations

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DRILLED SHAFTS

• Large Diameter Mono Drilled Shaft

FOUNDATION TESTING

• Thermal Integrity Profiler (TIP) Testing of

Drilled Shafts

• Statnamic Testing

• High Strain Dynamic Testing

October 12, 2016

12 Foot Diameter Drilled Shaft

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Due to a variety of reasons large diameter mono

drilled shafts are being used on TxDOT bridges.

October 12, 2016

Thermal Integrity Profiler (TIP) Testing

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Thermal Integrity Profiler (TIP):

- uses the temperature generated by curing cement (hydration energy) to assess the

quality of a drilled shaft.

- evaluates the entire cross-section and the entire length of the foundation. Results

are available shortly after shaft installation is concluded.

- reveals necks or inclusions, bulges, variations in concrete cover, shape of the

shaft and cage alignment.

October 12, 2016

Statnamic Testing

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The Statnamic load test is a type of

test for assessing the load carrying

capacity of deep foundations, which

is faster than a traditional load test.

October 12, 2016

High Strain Dynamic Testing

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High strain dynamic testing is a method

of testing deep foundations to:

• obtain information about

capacity

• obtain information about

integrity

• monitor their installation.

It is a standard test method in ASTM:

D4945-08 - Standard Test Method for

High-Strain Dynamic Testing of Piles.

Pile Driving Analyzer (PDA)

October 12, 2016

Deep Foundations for Transportation Facilities: A Historic Perspective

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TxDOT:

• utilizes deep foundations to support transportation facilities,

namely bridges.

• has a long and successful history with deep foundations for use

on bridges.

• has done a lot of leading edge research on drilled shafts, which

has advanced the use and knowledge of them.

Let’s see what advancements will be made in the future.

October 12, 2016

Deep Foundations for Transportation Facilities: A Historic Perspective

25

QUESTIONS?

October 12, 2016

Deep Foundations for Transportation Facilities: A Historic Perspective

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