pile design from constructability perspective - seaog · pile design from constructability...

Pile Design from Constructability Perspective

Prestressed Concrete Piles in Coastal Georgia

Presented by:

Guoming Lin, Ph.D., G.E., D.GE

Senior Principal / Senior Consultant

Savannah, Georgia

November 8, 2017

Outline

Geology and Geotechnical Challenges

Prestressed Concrete Piles in the Marl

o Marl Formation

o Driveability and Driving Stresses

o Setup and Freeze Bearing

Project Case History

o Georgia Ports Container Berth 8

o Truman Parkway Phase V

o Kinder Morgan Elba Island Terminal

Summary & Conclusions

Savannah is in Coastal Plain

Bedrock 1500 - 2000 ft deep

Three Geology Regions

Blue Ridge

Piedmont

Coastal Plain

Soil Strata in Savannah

Ref: Dames & Moore “ Talmadge Memorial Bridge Foundation Load Testing Report” Sept 1985.

Soft Clay Sand

Soft Limestone

Marl Formation

Silty Clay Sand

380’ boring

Floridian Limestone

SPT SamplesNo Rock Core

Soft Clay

Sand

Marl Formation

Soil Profile in upper 150 ft boring

Supported on 6 piles

Ground settled >12 inches below pile-supported building

Restroom for Hutchinson Island Golf

Elba LNG Terminal Administration Building

A new step every 5 yearsBuilding Constructed in 1975

Photo taken in 2002

Martin Marietta Aggregates / Marine Terminal

Soils have consistency close to peanut butter

Soil Bearing Failure/Mud Wave

Outline



o Marl Formation








Prestressed concrete piles

o Most commonly used along the Savannah River, Why?

All piles are supported in the Marl

o What is Marl?



PSC Piles

Advantages

Quality and reliability

Local experience

Corrosion resistant

Cost: less expensive

than steel H piles or

pipe piles or drilled

shafts

Disadvantages

Heavy to transport and

handle

Difficult to adjust length

Cost: more expensive

than timber pile, auger

cast piles

Marl

Loose or crumbling earthy

deposit (as of sand, silt, or clay)

that contains a substantial

amount of calcium carbonate

Miocene Formation-(5 to 23

million years ago)

Olive green and gray color

Marl

Marl, Origin and Characteristics

The Cooper Marl*

Skeletal remains of microscopic sea

organisms

Apparent over-consolidation due to

cementation

Uniform across the area

Constant properties along depth

SPT N=10 to 20, CPT tip qT~50 tsf,

VS~1500 fps, SU~4 ksf

* ref: W.M. Camp (2002) “Drilled and Driven

Foundation Behavior in Calcareous Clay” Proc.

GeoCongress, Orlando, FL.

Difference of Savannah Marl

Higher sand content

Less calcareous

Denser, SPT N=15 to 50, CPT tip qT~50 to

100 tsf

Pile driving difficulties: high blow counts

and limited penetration

High driving stresses and pile damage

Dense sandy silty claycan be excavated

imperious

Marl, Excavated at

SHEP Upper Water Intake Structure

Rincon, Georgia

PSC Pile Behaviors in the Marl in Savannah

High side frication capacities

High pore pressure (CPT or pile driving)

Setup/freeze effect

Low compressibility/settlement

Limited penetration

High driving stresses (~hammer)

Outline



o Marl Formation








GPA Container Berth 8

Kinder MorganElba Island Terminal

Truman ParkwayPhase V

Three Case Histories

Georgia Ports Garden City Terminal

The longest contiguous berth in the US

CB8 and 9

• Construction: barge mounted cranes

• Pile driving rig with swing lead

• Rigid steel framed templates

Dock: 1700 ft long

Subsurface Profile

Marl (silty sand clay, CL/CH)

SPT N ~ 20 to 60

+15, Top of dock

-16, Top of marl, undredged

-48, Dredge depth

+10, Ground surface on land

Ref: Lockwood Greene, GPA Container Berth 8 Dock, Aug 2003.

Pile Design

• Sizes: 20”, 18”, 16” square PSC

• Length: 60 to 98 ft

• Compression Capacities: 100 to 135 tons

Pile Test Program

• 11 Indicator piles with PDA testing

• PDA testing: initial driving, 6 or 7 day restrike

• Static Load Testing:

• 2 Compression tests

• 1 Tension test

Pile Test Results-Driveability and Stresses

Pile Hammer

• Model APE 46-32

• Rated Energy: 107.2 kips-ft

• Ram Weight: 10.1 kips

• Pile cushion: 9” thick plywood

Pile Casting Details

• 7000 psi concrete (actual>10,000 psi)

• 1000 psi effective prestressing

• Allowable Stress: compressive: 4.95 ksi

• Allowable Stress: tensile: 1.25 ksi

Driving Resistances (blow counts):

• 10 to 45 bpf in the marl

• Occasionally > 50 bpf in dense layers

• All driven to tip elevations

• No pile damage observed

Driving Stresses:

• Compressive: 2.4 to 4.7 ksi

• Tensile: 0.5 to 1.2 ksi

• Lower fuel setting to 2 to reduce driving

stresses

Pile Test Results-Pile Capacities

Max Load=360 tonsMax deflection=0.40 inchesPile did not fail

Max Load=440 tonsMax deflection=0.41 inchesPile did not fail

Pile Test Results-Setup Effect and Capacity Increases

Pile Capacity (tons)

Test Pile End of Initial Drive 6D/7D Restrike Increase (tons) Percent

IP4 (E-76) 368 412 192 52%

IP5 (E-66) 276 423 147 53%

IP6 (A-53) 264 493 229 87%

IP7 (A-18) 226 539 313 139%

IP8 (F-52) 248 486 238 96%

IP9 (P-39.7) 258 525 266 103%

IP10 (D-38) 140 256 115 82%

IP11 (E-24) 193 332 139 72%

IP12 (D-4) 247 277 29 12%

IP13 (F.5-61) 199 368 169 85%

IP14 (G-31) 253 526 273 108%

Average 192 81%

Piles at CB8

Over 2,000 Piles

Vertical and Horizontal Tolerance (rigid template)

Only One Pile Damaged

Truman Parkway V

Marsh and Vernon River

$72 million

1782 piles

16” for end bents

18” for intermediate bents

Design Load: 80 tons compression

Pile Casting Details-GDOT Standards

• 5000 psi concrete

• 734 psi prestressing

• Allowable Stress: compressive: 3.6 ksi

• Allowable Stress: tensile: 0.9 ksi

Pile Hammer

• Model ICE I-30

• Rated Energy: 71.7 kips-ft

• Ram Weight: 6.6 kips

• Pile cushion: 8” thick plywood

BFI Report

• Min tip elevation=-12 to -16 m

• Estimated tip elevation=-17 m

Pile Testing and Driving Conditions

Pile Testing:

• 17 probe piles along alignment

• GDOT does not require continuous monitoring

• End of Driving Blow Count as acceptance criteria

Driving Resistances (blow counts):

• Mostly normal driving, achieved the required bearing

• Occasionally > 50 bpf in dense layers

• Min tip was adjusted to -13 meters for a few bends

Truman Parkway Phase V

Pile Damage due to Tensile Driving Stress

PDA Testing and Driving Stresses

PDA Testing:

• Bent 44, 18” Square, 73.8 ft long and tip -12.1 m (-40 ft)

• CAPWAP Capacity 312 tons

Driving Stresses:

• Max compression stress: 3.0 ksi

• Max tension stress: 0.7 ksi

• Pile driving procedures were adjusted to avoid driving damage

Elba Island LNG Terminal

20,000 piles at the terminal>9,000 piles in current phase

SPT, CPT and DMT within 5 ft at Tank Center

Comparison of SPT, CPT and DMT Soundings

Comparison of SPT, CPT and DMT at Tank Center

T5B5 T5C5 T5D1SPTCPT DMT

Static Load Test-Setup

Static Test-Load Deflection Curves

Pile Instrumentation Plan

Piles cast at Standard Concrete ProductsSavannah, Georgia

Static Test-Unit Side Friction

Pile Driving Stressesand Damage

PDA Monitor

Test Pile No.

TypeAxial Load Test Results (tons)

EOD1 4DR2 6DSTN3

12DSLT4

TP1 18-in sq PPC 186 321 447

TP2 18-in sq PPC 189 316 373 425

TP3 17.7 in dia. ICP 123 322 430

TP4 18-in sq PPC Not Tested

TP5 18-in sq PPC 200 230

Axial Capacity Testing Program Summary.NOTES:

•EOD = End Of Driving (Dynamic)

•4DR = 4 Day Restrike (Dynamic)

•6D STN = 6 Day STATNAMIC test – SLD capacity

•12D SLT = 12 Day Static Load Test

Pile Setup Effect (Strength Gain over Time)

Average increases: 4 days=70%; 6 days=151%

Pile Driving Sequence

Started with peripheral rings

Over-densified sand layers

Predrilling required to complete pile driving

Liq

uid

Le

ve

l =

11

3 ft

Inner diameter = 252 ft

Outer diameter = 258 ft

68 ft 1600 18-inch Square

prestressed concrete piles

Elba Liquefaction Project (on-going)

• $2.4 billion project to convert the terminal into an LNG export facility

• 10 MMLS (movable modular liquefaction system)

• >9,000 prestressed concrete piles

Pile Test Program

• Prestressed concrete piles (18” and 14” square)

• Steel H piles

• Three types of auger cast piles: conventional auger, displacement and partial displacement piles

Very long caseDifficult drilling

Speed !Speed !Speed !

Very large hammer

High driving stress

Green concrete

No templates

Alignment

Outline



o Marl Formation








Conclusions

The Marl Formation is a reliable bearing stratum for piles. Marl has special

characteristics that affect pile foundation design and construction.

Prestressed concrete piles (PSC) have been the most popular foundation

system along the Savannah River.

Pile driving into the Savannah Marl can be difficult. Selection of pile hammer is

critical for pile drivability.

PSC piles are prone to damage by excessive driving stresses (compression and

tension). Using higher strength concrete and prestressing than the current

GDOT standards can help reduce the risk of pile damage.

The setup effect for PSC piles in the marl is very significant and should be taken

into account in the design and construction.

Acknowledgements

Clients: Georgia Ports, Georgia DOT, Chatham County, Kinder

Morgan

Partners: CH2M-Hill, Moffatt Nichol, Jacobs, CB&I, IHI E&C

Contractors: Orion Marine, Balfour Beatty, TIC, Bo-Mac, Cajun n

Standard Concrete Products

The Terracon Team (65+ strong in Savannah)

Thank You!

Any Questions / Comments ?

Guoming Lin, Ph.D., G.E., D.GE

Terracon Consultants

Savannah, Georgia

P: (912) 629 4000

E: [email protected]

pile design from constructability perspective - seaog · pile design from constructability...

Documents