Before Katrina one could describe levees as the …sections.asce.org/stlouis/Geotechnical...

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ASCE Fall Technical SeminarASCE Fall Technical Seminar

Standard of Practice for Levee DesignStandard of Practice for Levee Design

Chris GrovesChris GrovesOctober 2009October 2009

Before Katrina one could Before Katrina one could describe levees as the describe levees as the

stepchild of the engineeringstepchild of the engineeringstepchild of the engineering stepchild of the engineering professionprofession

After Katrina our attitude about the After Katrina our attitude about the risk posed by the levee system was risk posed by the levee system was

differentdifferent

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Even the Midwest floods of 1993 did Even the Midwest floods of 1993 did not cause us to rethink the risks. not cause us to rethink the risks.

After all, outside a few problems with After all, outside a few problems with federal levees, the levee system federal levees, the levee system

performed quite well. Overtopping of performed quite well. Overtopping of the agricultural levees had been the agricultural levees had been gg

expected and as a matter of policy expected and as a matter of policy this overtopping help protect the this overtopping help protect the

urban levees.urban levees.

Katrina managed to change our Katrina managed to change our understanding of acceptable levee understanding of acceptable levee

performance overnight. The lessons performance overnight. The lessons learned in the 1927 Mississippi River learned in the 1927 Mississippi River flood had long since been forgottenflood had long since been forgotten

Flooding criteria has led to most of Flooding criteria has led to most of the problems we have experiencedthe problems we have experienced

•• A 100A 100--year or greater flood has a 26% probability of year or greater flood has a 26% probability of occurrence in the life of a 30occurrence in the life of a 30--year mortgage. People are year mortgage. People are dropping the flood insurance when they have only 100dropping the flood insurance when they have only 100--year protection.year protection.

•• Banks require fire and storm insurance for much less likely Banks require fire and storm insurance for much less likely events. Banks should require flood insurance until a much events. Banks should require flood insurance until a much higher level of protection is provided.higher level of protection is provided.

•• From a public safety prospective, society should keep the From a public safety prospective, society should keep the general public out of the flood plain until a much higher general public out of the flood plain until a much higher level of protection is provided.level of protection is provided.

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How is flood frequency currently How is flood frequency currently being defined? The term “free board” being defined? The term “free board” is being replaced. Now it is the 90 or is being replaced. Now it is the 90 or

95 percent probability of 95 percent probability of nonexceedance.nonexceedance.

EM 1110EM 1110--22--1913 has become the 1913 has become the manual for levee design. Other manual for levee design. Other

documents are referenceddocuments are referenced

On the first page the document states On the first page the document states “Even though levees are similar to “Even though levees are similar to small earth dams they differ from small earth dams they differ from

earth dams in the following important earth dams in the following important respects:respects:

a)a) A levee embankment may become A levee embankment may become saturated for only a short period of timesaturated for only a short period of timesaturated for only a short period of time saturated for only a short period of time beyond the beyond the limit of capillary saturationlimit of capillary saturation,,

b)b) Levee alignment is dictated primarily by Levee alignment is dictated primarily by flood protection requirement, which often flood protection requirement, which often results in construction on poor foundation, results in construction on poor foundation, and….and….

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Modes of failure are identified as,Modes of failure are identified as,

•• OvertoppingOvertopping

•• Surface erosionSurface erosion

•• Internal erosion (piping)Internal erosion (piping)

•• Slides within the levee Slides within the levee embankment or the foundation embankment or the foundation soil.soil.

The differences in urban levees and The differences in urban levees and agricultural levees.agricultural levees.

•• Agricultural levees are generally constructed to Agricultural levees are generally constructed to provide a crest elevation above the 50provide a crest elevation above the 50--to100to100--yr level yr level of protection.of protection.

•• Agricultural levees were generally not designed by a Agricultural levees were generally not designed by a geotechnical engineer.geotechnical engineer.g gg g

•• Agricultural levees have seen poor construction and Agricultural levees have seen poor construction and repair practices.repair practices.

•• Urban levees have been constructed over the top of Urban levees have been constructed over the top of agricultural levees.agricultural levees.

•• Urban levees have had some borings and Urban levees have had some borings and geotechnical input.geotechnical input.

•• Urban levees protect lives.Urban levees protect lives.

Manual describes a phased Manual describes a phased investigation includinginvestigation including

Preliminary geological investigation Preliminary geological investigation including an office study based on available including an office study based on available information and a field survey to define the information and a field survey to define the topography, evidence of past problems, and topography, evidence of past problems, and natural and manmade features.natural and manmade features.

Subsurface explorations with two phases of Subsurface explorations with two phases of borings, test pits, geophysics, pump test, borings, test pits, geophysics, pump test, etc.etc.

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While aerial photographs are While aerial photographs are mentioned a geomorphologic study is mentioned a geomorphologic study is

not specifically describednot specifically described

Seepage and stability analysis are Seepage and stability analysis are described as the same scope one described as the same scope one

would do for a dam.would do for a dam.

•• Case I Case I –– End of ConstructionEnd of Construction

•• Case II Case II –– Sudden drawdownSudden drawdown

•• Case III Case III –– Steady Seepage from full flood stageSteady Seepage from full flood stage

C IVC IV E th k ( ll t i d)E th k ( ll t i d)•• Case IV Case IV –– Earthquake (normally not required)Earthquake (normally not required)

Steady Seepage becomes a problem for Steady Seepage becomes a problem for most unzoned homogenous most unzoned homogenous

embankments. When the phreatic embankments. When the phreatic surface breaks out on the face of the surface breaks out on the face of the

embankment the factor of safety drops. embankment the factor of safety drops. This issue is often addressed with one This issue is often addressed with one

f ff for more of the following.or more of the following.

•• A small cohesion of say 100 psf for clayA small cohesion of say 100 psf for clay

•• Ignoring shallow circles that do not reach the crest. Also Ignoring shallow circles that do not reach the crest. Also addressed in section 6addressed in section 6--8 of EM 1913.8 of EM 1913.

•• Transient seepage analysis (results subject to assumptions)Transient seepage analysis (results subject to assumptions)

•• A ruleA rule--ofof--thumb seepage geometry has been assumed.thumb seepage geometry has been assumed.

•• Seepage berms.Seepage berms.

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Factor of safety criteria are as followsFactor of safety criteria are as follows

•• 1.4 for steady seepage.1.4 for steady seepage.

•• 1.3 for end of construction 1.3 for end of construction

•• 1.0 to 1.2 for rapid drawdown1.0 to 1.2 for rapid drawdown

•• A series of exceptions are also A series of exceptions are also stated.stated.

Guidance for design of levees Guidance for design of levees generally follows guidance generally follows guidance

for earth dam.for earth dam.Then why does it appear that Then why does it appear that levees perform poorly in levees perform poorly in

comparison?comparison?

What are the principal hazards for What are the principal hazards for levees (failure modes)?levees (failure modes)?

•• OvertoppingOvertopping

•• UnderseepageUnderseepage

•• Slope StabilitySlope Stability

•• Through Seepage and Through Seepage and PenetrationPenetration

•• Animal BurrowsAnimal Burrows

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Overtopping Overtopping –– could be a low spot or could be a low spot or flood could exceed the designflood could exceed the design

Under seepage Under seepage –– starts as a small starts as a small boil and deteriorates with each floodboil and deteriorates with each flood

Slope instability Slope instability –– usually the result usually the result of a seepage problemof a seepage problem

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Through seepage Through seepage –– a construction a construction problem, a utility, or animal burrowproblem, a utility, or animal burrow

Animal BurrowAnimal Burrow

What is What is Acceptable Risk?Acceptable Risk?

•• What is risk?What is risk?

•• Who determines what is Who determines what is acceptable?acceptable?

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Risk = (probability) X (consequences)

DefinitionDefinition

Risk is never acceptable unconditionally. Risk is only acceptable if some benefit

can compensate for the risk

RiskRisk

can compensate for the risk.Fischhoff 1981

•• A dam is constructed for the A dam is constructed for the benefit of the owner of the dambenefit of the owner of the dam–– It is not acceptable to increase the It is not acceptable to increase the

risk to people downstream whorisk to people downstream who

DamsDams

risk to people downstream who risk to people downstream who receive no benefit.receive no benefit.

–– Therefore, we use very high Therefore, we use very high standards in the design and standards in the design and construction of a dam.construction of a dam.

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CriteriaCriteria

•• A levee is constructed for the A levee is constructed for the benefit of the people who live benefit of the people who live behind the leveebehind the levee

LeveesLevees

behind the levee.behind the levee.

•• Can they accept some risk?Can they accept some risk?

•• Engineers know that a dam Engineers know that a dam should have an impervious zone should have an impervious zone and a pervious drainage zoneand a pervious drainage zone——itit is not acceptable for seepage is not acceptable for seepage to breakout on the downstream to breakout on the downstream facefaceface.face.

•• Engineers followed the practice Engineers followed the practice of the farmers for the levees.of the farmers for the levees.

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Typical EmbankmentUSACE Manual

•• Farmers understood the risk.Farmers understood the risk.

•• They kept an eye on the river They kept an eye on the river and were quick to evacuate farm and were quick to evacuate farm equipment and personalequipment and personal

PerceptionsPerceptions

equipment and personal equipment and personal belongings.belongings.

•• Prosperous farmers would move Prosperous farmers would move family up on bluffs and continue family up on bluffs and continue farming flood plains.farming flood plains.

•• When the general public began When the general public began moving onto the flood plain they moving onto the flood plain they did not understand the risk.did not understand the risk.

•• They were often not sure where They were often not sure where


the river was located.the river was located.

•• They did not know what levees They did not know what levees looked like, who constructed looked like, who constructed them, or who maintained them.them, or who maintained them.

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•• The general public does not The general public does not know what a 100know what a 100--year levee is.year levee is.–– Does it mean that the flood comes Does it mean that the flood comes

about every 100 years?about every 100 years?


–– Does it mean that because there Does it mean that because there was a large flood 10 years ago was a large flood 10 years ago there will be 90 years before the there will be 90 years before the next one? “I don’t plan to live next one? “I don’t plan to live another 90 years, so I must be ok.”another 90 years, so I must be ok.”

•• “I am protected by a levee.”“I am protected by a levee.”–– Protected means there will never Protected means there will never

be a flood greater than the levee’sbe a flood greater than the levee’s


be a flood greater than the levee s be a flood greater than the levee s capability to protect.capability to protect.

•• Has this misconception of Has this misconception of terminology been cleared up by terminology been cleared up by FEMA and the USACE?FEMA and the USACE?


•• NO! But lately they have been NO! But lately they have been trying.trying.

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Congress and FEMACongress and FEMA

•• Has defined the Base Flood as Has defined the Base Flood as the flood with a 1 percent the flood with a 1 percent chance of exceedance on an chance of exceedance on an annual basis. annual basis.

•• When a levee provides When a levee provides protection for a flood with a 1% protection for a flood with a 1% probability, people within the probability, people within the protected zone are not required protected zone are not required to purchase flood insurance.to purchase flood insurance.

•• BAD IDEA!BAD IDEA!

•• In a 30In a 30--year period there is a year period there is a 26% chance that an event with a 26% chance that an event with a 1% annual probability will occur1% annual probability will occur

RealityReality

p yp y

•• People that pass on the flood People that pass on the flood insurance for their home are insurance for their home are betting they will not lose their betting they will not lose their greatest asset for the sake of greatest asset for the sake of saving on insurance.saving on insurance.

•• Most people in the Midwest have Most people in the Midwest have storm insurance. The banks storm insurance. The banks require it with the mortgage. Is require it with the mortgage. Is one home in four destroyed by one home in four destroyed by

RealityReality

tornados?tornados?

•• Who carries much of the blame Who carries much of the blame when the levee is overtopped?when the levee is overtopped?

•• USACE took the blame for New USACE took the blame for New Orleans.Orleans.

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From a social standpointFrom a social standpoint

•• What is wrong with the system?What is wrong with the system?

•• A 1% chance of failure each A 1% chance of failure each year is unacceptable when year is unacceptable when people understand the riskpeople understand the riskpeople understand the risk.people understand the risk.

•• Farmers want to sell the land for Farmers want to sell the land for development and retire.development and retire.

•• Developers want to develop the Developers want to develop the valuable floodplain near cities forvaluable floodplain near cities for

The path followedThe path followed

valuable floodplain near cities for valuable floodplain near cities for a profit.a profit.

•• Cities want the tax baseCities want the tax base

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•• Congress and FEMA has set a Congress and FEMA has set a standard with too much risk.standard with too much risk.

•• Engineers are willing to use a Engineers are willing to use a level of practice that results in level of practice that results in

Compounding riskCompounding risk

pptoo many failures.too many failures.

•• Home owners do not want to Home owners do not want to purchase the insurance.purchase the insurance.

•• Who is to blame?Who is to blame?

From an Engineering StandpointFrom an Engineering Standpoint

•• What is wrong with the system?What is wrong with the system?

•• Hydrology criteriaHydrology criteria——who would who would design a bridge or building with a design a bridge or building with a 26% chance of failure in a 3026% chance of failure in a 30--

EngineeringEngineering

year design life?year design life?

•• Geotechnical explorationGeotechnical exploration——who who would design a structure with would design a structure with borings spaced at 1,000 feet borings spaced at 1,000 feet with closer spacing at identified with closer spacing at identified problemsproblems

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•• Geotechnical analysisGeotechnical analysis——who who would design a dam without would design a dam without internal drainage features?internal drainage features?

EngineeringEngineering

•• Geotechnical stability and Geotechnical stability and underseepageunderseepage——who would who would consider observation during consider observation during loading to be an important tool to loading to be an important tool to find design deficiencies?find design deficiencies?

Finding the hidden problemFinding the hidden problem

120‐year flood

100‐year flood

Residual RiskResidual Risk

Levee

Residual Risk

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What have we learned and what What have we learned and what should we do?should we do?

•• Go for a 500Go for a 500--year (.2% year (.2% probability) criteria and stress probability) criteria and stress that there is still a 6% probabilitythat there is still a 6% probability

LessonsLessons

that there is still a 6% probability that there is still a 6% probability of failure in a 30of failure in a 30--year period, or year period, or suggest Probable Maximum suggest Probable Maximum Storm criteria used in sizing Storm criteria used in sizing spillways for damsspillways for dams

•• Stress the education of riskStress the education of risk

•• Stress that potential for loss of Stress that potential for loss of life should be considered in life should be considered in residential zoning. When aresidential zoning. When a

LessonsLessons

residential zoning. When a residential zoning. When a warehouse or factory is flooded warehouse or factory is flooded the risk to life is much lessthe risk to life is much less

•• Go for greater levee setbacks Go for greater levee setbacks from the river banksfrom the river banks

Questions???Questions???

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Design and Constructionof Micropiles

Fall Technical SeminarASCE Geotechnical Subcommittee – St. LouisOctober 30, 2009

John R. Wolosick, P.E.

Hayward Baker Inc.

Hayward Baker

2003

Calendar Art

Micropiles are…

High capacity (up to 500 tons design load), typically small diameter (2”-12”+) piles that are used in almost any type of ground to transfer structural load to competent bearing strata. Micropiles are easily installed in restricted access and limited headroom situations.

Also known as minipiles, pin piles, root piles, pipe piles, etc.

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Typical Micropile Program Involves

Drilling holes, 2”-12”+ diameter

The construction of a pile shaft consisting of high-strength steel pipes or steel bars

The filling of the hole with high strength cement grout

MicropilesDrilled and Grouted Steel Pipe Piles

Micropile Types

Soil Piles• Type S-1 – Composite Pile

• Type S-2 – Full Length Steel Pipe

Rock Piles• Type R-1 – Composite Pile

• Type R-2 – Full Length Steel Pipe

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Micropile TypesFounded inDense Soils

Founded in Rock

S-1 S-2 R-1 R-2

Micropile Installation Process

ConstructionSequenceS-1 Pile

Drill

Grout

Install reinforcement

Pressure Grout

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Construction SequenceR-1 Pile

Drill casing to rock

Drill rock socket

Grout

Install reinforcement

Micropiles –Typically Used For:

New Construction

Underpinning Existing Foundations

Limited Access or Headroom

Foundations where Obstructed Drilling is Required

Replacement for Drilled Shafts

Micropiles –Range of Ground Conditions:

Obstructions or Old Foundations

Variable Urban Fills

Karstic Limestone GeologyKarstic Limestone Geology

Glacial Till with Boulders

Mined Rock Geology

High Water Table

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Micropiles –Physical Constraints to Installation:

Limited Overhead Clearance

Limited Access

Vibration Sensitive EnvironmentsVibration Sensitive Environments

Settlement Sensitive Projects

Close Proximity to Existing Structures

Micropiles –Piling Materials:

Steel Pipe•API N80

•Yield Strength = 80 ksi

•Special Machine Flush Joint Threads

High Strength Steel Reinforcing BarsHigh Strength Steel Reinforcing Bars•Grade 75, 80, 95 or 150

Grout•Neat Cement

•Water / Cement Ratio = 0.45

•Strength = 4000 psi

3. Structural Design

Components• Cased length

• Uncased length

• Grout to steel bond

• Transitions between reinforcement types

• Strain compatibilityp y

• Casing or bar splice and connection

• Footing connection

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Structural Design (Internal):

Grout & steel Grout: 0.25-0.4*f’c{

Typical range of code allowable stresses(ASD):

Transfer zone (plunge)

Bond zone

Steel: 0.3-0.47*fy

{{

Connection Details

Shear transfer from grout

Bearing plate

Shear rings

Bearing Plate

Stiffener

Hewlett Packard Corvallis, ORSeismic Upgrade Connection

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Micropiles –Geotechnical Aspects of Piles:

Friction Bond – Soil or Rock!

Compression and Tension Loads

20 – 500+ tons Working Load20 500 tons Working Load

Lateral Load Capacity: 5 – 15 tons

Battering is not a problem

MicropilesMicropiles

for thefor the

SpalationSpalation Neutron Source Neutron Source FACILITYFACILITY

OAK RIDGE, TENNESSEEOAK RIDGE, TENNESSEE

Hayward Baker/Nicholson JVHayward Baker/Nicholson JV

SITEOak Ridge

NashvilleKnoxville

Chattanooga

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Y-12

OAK RIDGE

SITEETT Park(ORGDP)

ORNL

- Lawrence Berkeley

Los Alamos/Jefferson

- Oak Ridge

- Brookhaven

Argonne/Oak Ridge

Project Information

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Project Scope

• Layers of weathered rock, soil filled cavities • Anticipated depths ranged from 40 to 200 ft. • Owner required three drilling operations

186 l d d h d l• 186 calendar day schedule

Project Scope

• Total of 1087 -- 12 inch dia. Minipiles in bid• 400 kip compression & tension capacity• 60 kip lateral load • Install four No 6 rebar w/#3 cage - top 8 ftInstall four No. 6 rebar w/#3 cage top 8 ft.• Install ten feet into bedrock in karst terrain

Alternate Bid Submitted

• 9-5/8 in. dia. w/0.545 in. wall to full depth

• 11-7/8 in dia. w/0.534 in. wall upper 20 ft.

• Single rebar of adequate size

• Two predrill rigs for open hole drilling

• Two drill rigs for installation of pipe

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Site Conditions

Bldg. North

SNS Site -- October, 2000

TOP OF SOUND ROCK

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TOP OF SOUND ROCK

Project Conditions

Office Area

Equipment

Laydown & Cutting Yard

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Air Compressor Bank & Batch Plant Operations

Working Area

200 ton crane w/power unit

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Hydraulic Drill Motor

Drilling with DHH, air & water

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Typical Operation

Pipe Installation Operation

Setting 11-7/8 in. pipe

w/100 ton service crane

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Pipe Installation

Completed Pile prior to

Rebar Extension

Pile Load Tests• Compression Tests - 4 planned

(4 test & 1 production pile conducted) 800 Kips

• Tension Tests 2 planned (2 conducted) • Tension Tests - 2 planned (2 conducted) 800 Kips

• Lateral Tests - 2 planned (2 conducted) 60 Kips

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Compression Test

Tension Test

T-3 Installation

Lateral Test

L-1 Pile

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Compression Test C-3B

0

0.2

0.4

0.6

0 100 200 300 400 500 600 700 800 900

Load (kips)

es)

Pile Butt Deflection

Telltale Deflection

Load (kips)

Compression Test C-3B

0.8

1

1.2

1.4

1.6

Def

lect

ion

(in

ch

Deflection

Project Challenges

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Available Work Area

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Rebar Forest

PROJECT ANALYSIS

• Projected No. of Piles ------ 1,087

• Actual No. of Piles ---------- 937

• Projected Drilling Footage - 113,500

• Actual Drilling Footage ----- 95,240

• Projected Grout Qty. (cyd) - 13,500

• Actual Grout Qty. (cyd) ----- 10,560

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GKN Aerospace Press Mat FoundationSt. Louis, Missouri

A new machining press with movable static loads required a thick concrete mat supported on many lightly loaded friction piles

The pile section provided by HBI satisfied the structural engineer’s specifications for deflection

GKN owned Hayward Baker

until 1990!

GKN Aerospace Press Mat FoundationSt. Louis, Missouri

Subsurface Exploration Location Sketch

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Boring Log

Log of CPT

Micropiles were installed using DK50 and Klemm 708 rigs working in limited headroom

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Load Test Set-up and Reaction Frame

GKN Aerospace Press Mat FoundationSt. Louis, MissouriLoad Test

The End

Q ti ?Questions?

10/28/2009

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AUGER CAST PILESAUGER CAST PILES

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Richard W. Stephenson, Ph.D., P.E.Richard W. Stephenson, Ph.D., P.E.

AugerAuger--Cast PilesCast Piles

Also Known As:Also Known As:–– Augered Pressure Grouted Pile (APG)Augered Pressure Grouted Pile (APG)–– Augered CastAugered Cast--inin--Place PilesPlace Piles

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–– Continuous Flight Auger PilesContinuous Flight Auger Piles–– Intruded Mortar PilesIntruded Mortar Piles–– Auger PilesAuger Piles–– Grouted Bored PilesGrouted Bored Piles–– Augered GroutAugered Grout--Injected PilesInjected Piles

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AugerAuger--Cast PilesCast Piles

0.3 to 0.9 m (12 to 36) Inches Diameter

Up to 30 m (100 feet) Deep

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p ( ) p

Capacities as for Driven Piles of Same Size

Single pilesSingle piles–– Sound wallSound wall–– Light poleLight poleLight poleLight pole

GroupsGroups–– BridgesBridges–– Etc.Etc.

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ReinforcementReinforcement

Confined to upper 10 to 15 m (33Confined to upper 10 to 15 m (33--50 ft)50 ft)Occasionally full length reinforcementOccasionally full length reinforcement

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Differences between ACIP and Differences between ACIP and drilled shaftsdrilled shafts

The main difference is that the use of The main difference is that the use of casing or slurry to temporarily support casing or slurry to temporarily support the hole is avoided.the hole is avoided.

Drilling the hole in one continuous Drilling the hole in one continuous process is faster than drilling a shaft process is faster than drilling a shaft excavation,excavation,

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The torque requirement to install the The torque requirement to install the continuous auger is high compared with continuous auger is high compared with a conventional drilled shaft of similar a conventional drilled shaft of similar diameter; therefore, diameter; therefore,

The diameter and length of ACIP piles The diameter and length of ACIP piles g pg pare generally less than drilled shafts.are generally less than drilled shafts.

The use of a continuous auger for The use of a continuous auger for installation also limits ACIP piles to soil installation also limits ACIP piles to soil or very weak rock profilesor very weak rock profiles

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Differences between ACIP and Differences between ACIP and driven pilesdriven piles

Noise and vibration due to pile driving Noise and vibration due to pile driving are minimizedare minimized

ACIP piles also eliminate splices and ACIP piles also eliminate splices and cutoffs.cutoffs.

Soil heave due to driving can be Soil heave due to driving can be eliminatedeliminated

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A disadvantage of ACIP piles A disadvantage of ACIP piles compared to driven piles is that compared to driven piles is that the available QA methods to verify the available QA methods to verify the structural integrity and pile the structural integrity and pile bearing capacity for ACIP piles are bearing capacity for ACIP piles are less reliable than those for driven less reliable than those for driven pilespilespiles.piles.

Another disadvantage of ACIP piles Another disadvantage of ACIP piles is that ACIP piles generate soil is that ACIP piles generate soil spoils that require collection and spoils that require collection and disposal.disposal.

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Construction Techniques Construction Techniques and Materialsand Materials

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Drill RigsDrill RigsCrane Crane MountedMountedContinuousContinuous--flight hollowflight hollow--stem augerstem augerCrowdCrowdCrowd Crowd limited to limited to total weight total weight of gearbox, of gearbox, augers above augers above ground and ground and soil on auger soil on auger flightsflights

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torque capacities torque capacities for cranefor crane--attached rigs attached rigs range from 20 to range from 20 to 120 kN120 kN--m m (15,000 to (15,000 to 90,000 ft90,000 ft--lbs);lbs);

7 to 50 kN7 to 50 kN mm7 to 50 kN7 to 50 kN--m m (20,000 to (20,000 to 36,000 ft36,000 ft--lbs) lbs) are most are most common for common for private private commercial commercial work.work.

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Hydraulic Rig

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Grout or Concrete?Grout or Concrete?

Grout mixes are sometimes preferred for easier Grout mixes are sometimes preferred for easier insertion of steel reinforcement into the pile;insertion of steel reinforcement into the pile;

Grout mixes tend to be more fluid and have Grout mixes tend to be more fluid and have greater workability; andgreater workability; andgreater workability; andgreater workability; and

Grout mixes tend to be easier to pump, and Grout mixes tend to be easier to pump, and many contractors, who have historically used many contractors, who have historically used grout mixes, have grout pumps and equipment grout mixes, have grout pumps and equipment that may not be suitable for use with concrete.that may not be suitable for use with concrete.

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Grout will generally have a higher unit cost than Grout will generally have a higher unit cost than concrete;concrete;

Grout will tend to have a slightly lower elastic Grout will tend to have a slightly lower elastic modulus than concrete; andmodulus than concrete; and

Grout will tend to be less stable within the hole Grout will tend to be less stable within the hole when drilling through extremely soft soils (such as when drilling through extremely soft soils (such as organic clays or silt).organic clays or silt).

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Wider acceptance of ACIP Piles in Wider acceptance of ACIP Piles in commercial rather than commercial rather than

transportationtransportationSimple foundation requirements: a large number of Simple foundation requirements: a large number of piles are commonly used in a compact area primarily piles are commonly used in a compact area primarily to support large concentrated dead loads.to support large concentrated dead loads.

S d f i t ll ti f ACIP il th ilS d f i t ll ti f ACIP il th ilSpeed of installation of ACIP piles over other pile Speed of installation of ACIP piles over other pile types.types.

Increased use of designIncreased use of design--build contracting in private build contracting in private work, in which contractors are highly motivated work, in which contractors are highly motivated toward speed, economy, and innovations to those toward speed, economy, and innovations to those means.means.

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Increased requirements to minimize noise and Increased requirements to minimize noise and vibrations from pile installation in heavily populated vibrations from pile installation in heavily populated areas.areas.

A reluctance by many owners to utilize ACIP piles A reluctance by many owners to utilize ACIP piles because of concerns about quality control and because of concerns about quality control and structural integrity.structural integrity.

The typical demand on bridges for uplift and lateral The typical demand on bridges for uplift and lateral load capacity, scour considerations, and/or seismic load capacity, scour considerations, and/or seismic considerations, require pile diameters and possibly considerations, require pile diameters and possibly lengths up to a range not commonly used with ACIP lengths up to a range not commonly used with ACIP piles in private commercial work in U.S. markets.piles in private commercial work in U.S. markets.

10/28/2009 27

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10

Advantages and Advantages and Limitations of ACIP PilesLimitations of ACIP Piles

10/28/2009 28

Limitations of ACIP PilesLimitations of ACIP Piles

Favorable Geotechnical Favorable Geotechnical ConditionsConditions

Medium to very stiff clay soils.Medium to very stiff clay soils.–– clays are generally stable during drilling clays are generally stable during drilling

and less subject to concerns about soil and less subject to concerns about soil i i d i d illii i d i d illi

10/28/2009 29

mining during drilling.mining during drilling.

Cemented sands or weak limestoneCemented sands or weak limestone

Residual soils.Residual soils.

Medium dense to dense silty sands and Medium dense to dense silty sands and wellwell--graded sands.graded sands.

Rock overlain by stiff or cemented Rock overlain by stiff or cemented deposits.deposits.

10/28/2009 30

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11

Unfavorable Geotechnical Unfavorable Geotechnical ConditionsConditions

Very soft soils.Very soft soils.

Loose sands or very clean uniformly Loose sands or very clean uniformly graded sands under groundwatergraded sands under groundwater

10/28/2009 31

graded sands under groundwatergraded sands under groundwater

Geologic formations containing voids, Geologic formations containing voids, pockets of water, lenses of very soft pockets of water, lenses of very soft soils, and/or flowing water.soils, and/or flowing water.

Hard soil or rock overlain by soft soil or Hard soil or rock overlain by soft soil or loose, granular soil.loose, granular soil.

SandSand--bearing stratum underlying stiff bearing stratum underlying stiff clay.clay.

Highly variable ground conditions.Highly variable ground conditions.

Conditions requiring penetration of very Conditions requiring penetration of very hard strata.hard strata.

10/28/2009 32

Ground conditions requiring Ground conditions requiring uncommonly long piles.uncommonly long piles.

Ground conditions with deep scour or Ground conditions with deep scour or liquefiable sand layers.liquefiable sand layers.

10/28/2009 33

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12

Project Conditions Project Conditions Affecting the Selection and Affecting the Selection and

Use of ACIP PilesUse of ACIP PilesUse of ACIP PilesUse of ACIP Piles

10/28/2009 34

Projects where speed of installation is Projects where speed of installation is important.important.

Batter Piles Required.Batter Piles Required.

P j t h l b f ilP j t h l b f ilProjects where large numbers of piles Projects where large numbers of piles are required.are required.

Low headroom conditions.Low headroom conditions.

10/28/2009 35

Secant or tangent pile walls up to 10 m Secant or tangent pile walls up to 10 m (33 ft) of exposed wall height.(33 ft) of exposed wall height.

Sound walls in favorable soil conditionsSound walls in favorable soil conditions

PilPil t d b k tt d b k tPilePile--supported embankments.supported embankments.

10/28/2009 36

10/28/2009

13

10/28/2009 37

10/28/2009 38

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10/28/2009

14

EVALUATION OF STATIC EVALUATION OF STATIC CAPACITY OFCAPACITY OF

AUGEREDAUGERED CASTCAST ININ PLACEPLACEAUGEREDAUGERED--CASTCAST--ININ--PLACE PLACE PILESPILES

10/28/2009 40

General Design EquationGeneral Design Equation

where,– qp = ultimate unit

end bearing capacity

10/28/2009 41

end bearing capacity,– Ab = cross-sectional

area of the pile base,– fs = ultimate unit

friction capacity, and– As = perimeter area

of the pile.

ssbpultv AfAqQ ⋅+⋅=,

The behavior of ACIP piles falls somewhere between that of drilled

10/28/2009 42

somewhere between that of drilled shafts and driven piles

10/28/2009

15

ZeladaZelada and Stephenson and Stephenson (2000)(2000)

SCOPE OF WORKSCOPE OF WORK

This study compared computed theoretical load capacity using eight different published

10/28/2009 43

p y g g ptechniques, with the results from a field load test database of ACIP piles constructed in cohesionless soils. Recommendations were made regarding the design approach most appropriate for these foundations and the best procedure for estimating ultimate capacity from pile load tests.

Auger Cast Piles Auger Cast Piles –– Sand Sand ––Tip CapacitiesTip Capacities

Empirical formulas based on sixty load tests Empirical formulas based on sixty load tests on piles from 12 to 24 inches diameteron piles from 12 to 24 inches diameter

Embedments of from 15Embedments of from 15--85 feet85 feet

44

Embedments of from 15Embedments of from 15 85 feet85 feet

Capacity is based on the auger diameter, not Capacity is based on the auger diameter, not the eventual constructed pile diameter.the eventual constructed pile diameter.

FHWA 1999 FHWA 1999

tsfNpq 759.1 ≤=Neely (1991)

10/28/2009 45

75Nfor 3.4)(

75N0for 6.0 )(

6060

6060

>=

≤≤=

NMPaq

Ntsfq

p

p

N60 is the SPT-N value at 60% efficiency near the tip of the pile (1 diameter above to 2 or 3 diameters below the pile tip)

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16

Auger Cast Piles Auger Cast Piles –– Sand Sand ––Side CapacitiesSide Capacities

10/28/2009 46

Side CapacitiesSide Capacities

Neely (1991)

tsfpf os 4.1' ≤⋅= β

10/28/2009 47

Wright and Reese (1978) (McVay et al., 1994)

tsfKpf 61tan' ≤= φ

Where– Ks is taken as 1.1, – p’o is the

ff ti

10/28/2009 48

tsfKpf ss 6.1tan0 ≤= φ average effective stress along the length of the pile and

– φ is the angle of internal friction of the soil

tsfNdq 403

205.0

≤⋅=

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17

Reese and O’Neill (FHWA, 1988)

The end bearing is taken as 0.6N (tsf) at the

2.125.0135.05.1tan 5.0 ≤≤−==⋅ ββφ zK

10/28/2009 49

The end bearing is taken as 0.6N (tsf) at thetip, for N values less than 75.For N values greater than 75, the unit endbearing is assumed to be a constant 45 tsf (4MPa).

RESULTSRESULTS

10/28/2009 50

New EquationsNew EquationsZeladaZelada and Stephenson (2000)and Stephenson (2000)

5.0108.02.1 z−=βf 'β

10/28/2009 51

tsfNqb 757.1 ≤⋅=

os pf '⋅= β

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18

TIP RESISTANCETIP RESISTANCE

200

250

300 350

400

Tip stan

Meyerhof (Driven Piles)

represent derived values from measured loads.

10/28/2009 52

0

50

100 150

200

0 20 40 60 80 100

SPT N-value

sf)

Neely

Reese & O'Neill

Avg. Unit Tip = 1.7N

COHESIVE SOILCOHESIVE SOIL

10/28/2009 53

American Petroleum Institute (16) Cohesive Soil The shaft friction in cohesive soil can be calculated at any point along the pile by the following:

fs = αcu (24)

where α = a dimensionless factor cu = undrained shear strength of the soil at the point in

10/28/2009 54

question α = 0.5ψ-0.5 for ψ ≤ 1 (25) α = 0.5ψ-0.25 for ψ > 1 (26) with the constraint that α ≤ 1.0. ψ = cu/σv’ for the point of interest (27) where σv’ = effective overburden pressure at the point in question.

10/28/2009

19

FHWA 1999FHWA 1999

51/f550 ≤= us

P

cf α

10/28/2009 55

5.1/cfor 55.0 u ≤= aPαPa = atmospheric pressure

The unit point resistance for piles in bearing in cohesive soil can be calculated by the following

10/28/2009 56

cohesive soil can be calculated by the following.qp = 9cu

FHWA

Coyle et. al

API

Unconservative Conservative

10/28/2009 57

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75

Measured/Predicted Load Ratio

LPC

German Standard

10/28/2009

20

AUGER CAST PILESAUGER CAST PILESQA/ACQA/AC

10/28/2009 58

Richard W. Stephenson, Ph.D., P.E.Richard W. Stephenson, Ph.D., P.E.

Recommended RecordsRecommended Records

1. Pile location and plumbness;

2. Ground surface elevation;

59

3. Pile toe (bottom) depth/elevation;

4. Depth/Elevation of top of grout/concrete;

5. Pile length;

6. Auger diameter;

7. Details of the reinforcing steel (number, size, and grade of longitudinal bars, size andspacing of transverse steel; outside diameter and length of cage);

8. Flow cone efflux time and volume of grout placed,

60

g p ,or slump and volume of concreteplaced;

9. Theoretical volume of excavation (theoretical diameter = diameter of auger);

10. Depth/Elevation to which reinforcing steel was placed;

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21

11. Date/Time of beginning of drilling;

12. Date/Time of completion of drilling;

13. Date/Time grout or concrete was mixed;

14. Date/Time ready-mix grout or concrete truck i d t j t it d i f ll

61

arrived at project site, and copies of allgrout or concrete batch tickets used for the pile construction;

15. Date/Time of beginning of grout or concrete pumping;

16. Date/Time of completion of grout or concrete pumping;

17. Date/Time of placement of reinforcing steel;

18. Weather conditions, including air temperature, at time of grout or concrete placement;

19. Identification of all grout or concrete samples taken from the pile;

20. All other pertinent data relative to the pile installation; and

21. All readings made by the automated measuring and recording equipment to include as a minimum:

a. auger rotation vs. depth for every 0.6-m (2-ft) increment, or less, of pile advancement during the drilling process, and during placement of grout orconcrete (if auger is rotated during this placement);concrete (if auger is rotated during this placement); and

b. volume of grout or concrete placed versus depth of outlet orifice for every 0.6-m(2-ft) increment, or less, of pile placed;

10/28/2009

22

c. Average maximum and minimum pump stroke pressures at ground level for every0.6-m (2-ft) increment, or less, of pile placed;

d. Average maximum and minimum pump stroke pressure at or near the auger headfor every 0.6-m (2-ft) increment, or less, of pile placed, if directed by the engineer; andy g ;

e. Additionally, the engineer may also specify that the torque and crowd force (downward thrust on auger) measurements be made at every 0.6-m (2-ft)increment, or less, of pile advancement during the drilling process.

PERFORMANCE PERFORMANCE MONITORING AND MONITORING AND CONTROL DURING CONTROL DURING CONSTRUCCTIONCONSTRUCCTION

Past PracticePast Practice

••Importance of a skilled operatorImportance of a skilled operator

••Use of visual observations of the Use of visual observations of the drillingdrilling

••Crude estimates of grout/concrete Crude estimates of grout/concrete pumpedpumped

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23

MONITORING AND MONITORING AND CONTROL OF THE CONTROL OF THE DRILLING PHASEDRILLING PHASEDRILLING PHASEDRILLING PHASE

Goals of Monitoring and Control:Goals of Monitoring and Control:

•Ensure that excessive flighting of soil does not occur and

•The appropriate level of soil displacement occurs

General Guidelines for Auger Penetration Rate for CFA Piles

Soil Type Rate of Penetration(Revolutions per Auger Pitch)

Clay soils 2 to 3

Cohesionless soils 1.5 to 2

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24

••In the Manual Control System:In the Manual Control System:

•Auger speed is predetermined by the gearbox setting

•The depth of penetration is monitored by direct observation of the to of the auger in the leads, and

•The rate of penetration is observed using a stopwatch.

Better method:Better method:

•Depth encoder and revolution counter to monitor and display the rate of penetration graphically in units of revolutions per meter of penetration

•Use with hydraulic fixed mast drilling equipment that allows control of crowd, torque and speed of revolution.

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25

Crane Mounted:Crane Mounted:

•Depth encoder and a clock to monitor the rate of penetration.

•The speed of auger rotation is controlled via the bgearbox.

Monitoring and Control of the Monitoring and Control of the Grouting/Concreting PhaseGrouting/Concreting Phase

••Perhaps the most important aspect of QA/QC Perhaps the most important aspect of QA/QC for ACIP Pilesfor ACIP Piles

••Objective: Adequate grout or concrete be Objective: Adequate grout or concrete be delivered to the discharge point of the auger at delivered to the discharge point of the auger at the proper pressure.the proper pressure.

••Both pressure and volume must be monitored Both pressure and volume must be monitored as a function of auger depth.as a function of auger depth.

••Monitor the extraction of the auger.Monitor the extraction of the auger.

••The lift speed of the auger must be controlled The lift speed of the auger must be controlled so that the proper volume of concrete is so that the proper volume of concrete is delivered under sufficient pressure. delivered under sufficient pressure.

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26

••Observe and document:Observe and document:••Position of the auger tipPosition of the auger tip••Lifting speedLifting speed••Volume of grout/concrete deliveredVolume of grout/concrete delivered••Pressure with which the grout/concrete is Pressure with which the grout/concrete is delivered.delivered.

The manual method of monitoring and documenting The manual method of monitoring and documenting the grouting/concrete operation involves the the grouting/concrete operation involves the following:following:

• the position of the auger tip is monitored visually by observing the height of the augerin the leads;

• the lifting speed is controlled by the operator by feel and by observing the height ofthe auger in the leads while timing the withdrawal using a stopwatch;

• the volume of grout is measured by estimating the volume per stroke of the pump, and by manually counting the pump strokes; and

• the pressure with which the grout is p gdelivered is monitored by a gauge in the line near the pump.

10/28/2009

27

The system recommended for transportation projects includes automated monitoring of the augerposition; volume of grout/concrete that is delivered; pressure with which it is delivered; and rotation and lifting speed of the auger. Such system should provide the following:

• the position of the auger tip [monitored automatically by a position sensor ;

• the volume of grout [measured by an in-line flowmeter that provides a reliable and accurate measure of the grout/concrete that is delivered in real time];

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28

•the pressure with which the grout/concrete is delivered [monitored using a gauge in theline near the swivel at the top of the auger, or in the auger itself near the tip (latter option is better)];

• the rotation of the auger [monitored by a sensor];

• the lifting speed [controlled by the operator based on real time observation of the control parameters notedreal time observation of the control parameters noted above, displayed graphically in the cab of the rig, and compared to target values]; and

• the entire operation [recorded as a part of the documentation process].

CONCLUSIONSCONCLUSIONSACIP Piles are becoming a dominant ACIP Piles are becoming a dominant player in the Midwestplayer in the Midwest

Resistance to use is primarily related to Resistance to use is primarily related to p yp ythe lack of conventional QA/QC the lack of conventional QA/QC proceduresprocedures

Design equations existDesign equations exist

84

10/28/2009

29

ReferencesReferencesDan A. Brown, Ph.D., P.E., Steven D. Dapp, Ph.D., P.E., W. Robert Dan A. Brown, Ph.D., P.E., Steven D. Dapp, Ph.D., P.E., W. Robert Thompson, III, P.E., and Carlos A. Lazarte, Ph.D., P.E., GEOTECHNICAL Thompson, III, P.E., and Carlos A. Lazarte, Ph.D., P.E., GEOTECHNICAL ENGINEERING CIRCULAR NO. 8 Design and Construction of Continuous ENGINEERING CIRCULAR NO. 8 Design and Construction of Continuous Flight Auger (CFA) PilesFlight Auger (CFA) PilesBustamante, M., and Gianeselli, L. (1981). “Portance Réele et Portance Bustamante, M., and Gianeselli, L. (1981). “Portance Réele et Portance Calculée des Pieux Isolés Sollicités Verticalement,” Revue Francaise de Calculée des Pieux Isolés Sollicités Verticalement,” Revue Francaise de Geotéchnique, No. 16, Presses de l’ Geotéchnique, No. 16, Presses de l’ ENPC, France.ENPC, France.Bustamante, M., and Gianeselli, L. (1982). “Pile Bearing Capacity by Bustamante, M., and Gianeselli, L. (1982). “Pile Bearing Capacity by Means Means of of Static Penetrometer Static Penetrometer CPT,” In Proceedings of the 2nd CPT,” In Proceedings of the 2nd

10/28/2009 85

, g, gEuropean Symposium on European Symposium on Penetration TestingPenetration Testing. Amsterdam, pp. 493. Amsterdam, pp. 493––500.500.Chin, F.K. (1970). “Estimation of the Ultimate Load of Piles not Carried Chin, F.K. (1970). “Estimation of the Ultimate Load of Piles not Carried to Failure,” Proceedings of the Second Southeast Asian Conference on to Failure,” Proceedings of the Second Southeast Asian Conference on Soil Engineering, Singapore, Vol. 1, pp. 81Soil Engineering, Singapore, Vol. 1, pp. 81––90.90.Clemente, J.L.M., Davie, J.R., and Senapathy, H. (2000). “Design and Clemente, J.L.M., Davie, J.R., and Senapathy, H. (2000). “Design and Load Testing of Augercast Piles in Stiff Clay,” Geotechnical Special Load Testing of Augercast Piles in Stiff Clay,” Geotechnical Special Publication No. 100, Ed. By N. D. Dennis, R. Castelli, and M. W. O’Neill Publication No. 100, Ed. By N. D. Dennis, R. Castelli, and M. W. O’Neill (Eds.), ASCE, August, pp. 398(Eds.), ASCE, August, pp. 398––403.403.

Coleman, D.M. and Arcement, B.J. (2002). “Evaluation of Design Coleman, D.M. and Arcement, B.J. (2002). “Evaluation of Design Methods for Auger Cast Piles in Mixed Soil Conditions,” Proceedings of Methods for Auger Cast Piles in Mixed Soil Conditions,” Proceedings of the International Deep Foundations Congress 2002, February 14the International Deep Foundations Congress 2002, February 14--16, 16, 2002 Orlando, Florida; M.W. O’Neill and F.C. Townsend (Eds.), ASCE, 2002 Orlando, Florida; M.W. O’Neill and F.C. Townsend (Eds.), ASCE, pp. 1404pp. 1404––1420.1420.Coyle H. M., and Castello, R. R. (1981). “New Design Correlations for Coyle H. M., and Castello, R. R. (1981). “New Design Correlations for Piles on Sand,” Journal of the Geotechnical Engineering Division, ASCE, Piles on Sand,” Journal of the Geotechnical Engineering Division, ASCE, Vol. 106 No. GT7, pp. 965Vol. 106 No. GT7, pp. 965––986.986.Decourt, L. (2003). “Behaviour of a CFA Pile in a Lateric Clay,” Decourt, L. (2003). “Behaviour of a CFA Pile in a Lateric Clay,” Proceedings of the 4Proceedings of the 4thth International Geotechnical Seminar on Deep International Geotechnical Seminar on Deep Foundations on Bored and Auger Piles, BAP IV, Ghent, Belgium, pp. Foundations on Bored and Auger Piles, BAP IV, Ghent, Belgium, pp. 301301––308.308.DFI (2005). “Manual for Non Destructive Testing and Evaluation of DFI (2005). “Manual for Non Destructive Testing and Evaluation of Drilled Shafts”, Deep Foundations Institute, Chernauskas, L.E. (Ed.) Drilled Shafts”, Deep Foundations Institute, Chernauskas, L.E. (Ed.) Hawthorne, NJ.Hawthorne, NJ.Douglas, D. J. (1983). “Discussion on Paper 17Douglas, D. J. (1983). “Discussion on Paper 17--22: Case Histories,” 22: Case Histories,” Proceeding, Conference on Piling and Ground Treatment, Institution of Proceeding, Conference on Piling and Ground Treatment, Institution of Civil Engineering, London, pp. 283.Civil Engineering, London, pp. 283.

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Fleming, W.G.K. (1995). “The Understanding of Continuous Flight Fleming, W.G.K. (1995). “The Understanding of Continuous Flight Auger Piling, Its Monitoring and Control,” Proceedings, Institution of Auger Piling, Its Monitoring and Control,” Proceedings, Institution of Civil Engineers Geotechnical Engineering, Vol. 113, July, pp. 157Civil Engineers Geotechnical Engineering, Vol. 113, July, pp. 157––165. 165. Discussion by R. SmythDiscussion by R. Smyth--Osbourne and reply, Vol. 119, Oct., 1996, p. Osbourne and reply, Vol. 119, Oct., 1996, p. 237.237.Frizzi, R.P. and Meyer, M.E. (2000). “Augercast Piles: South Florida Frizzi, R.P. and Meyer, M.E. (2000). “Augercast Piles: South Florida Experience,” Geotechnical Special Publication No. 100, N. D. Dennis, R. Experience,” Geotechnical Special Publication No. 100, N. D. Dennis, R. Castelli, and M. W. O’Neill (Eds.), ASCE, August, pp. 382Castelli, and M. W. O’Neill (Eds.), ASCE, August, pp. 382––396.396.McVay, M., Armaghani, B, and Casper, R. (1994). “Design and McVay, M., Armaghani, B, and Casper, R. (1994). “Design and Construction of AugerConstruction of Auger--Cast Piles in Florida,” Transportation Research Cast Piles in Florida,” Transportation Research Record 1447 Design and Construction of Auger Cast Piles and OtherRecord 1447 Design and Construction of Auger Cast Piles and OtherRecord 1447, Design and Construction of Auger Cast Piles, and Other Record 1447, Design and Construction of Auger Cast Piles, and Other Foundation Issues, Washington, pp. 10Foundation Issues, Washington, pp. 10––18.18.Neely, W. J. (1991) “Bearing Capacity of AugerNeely, W. J. (1991) “Bearing Capacity of Auger--Cast Piles in Sand,” Cast Piles in Sand,” Journal of Geotechnical Engineering, ASCE, Vol. 117, No. 2, pp. 331Journal of Geotechnical Engineering, ASCE, Vol. 117, No. 2, pp. 331––345.345.O’Neill, M. W., Ata, A., Vipulanandan, C., and Yin, S. (2002). “Axial O’Neill, M. W., Ata, A., Vipulanandan, C., and Yin, S. (2002). “Axial Performance of ACIP Piles in Texas Coastal Soils,” Geotechnical Special Performance of ACIP Piles in Texas Coastal Soils,” Geotechnical Special Publication No. 116, Ed. by M. W. O’Neill and F. C. Townsend (Eds.), Publication No. 116, Ed. by M. W. O’Neill and F. C. Townsend (Eds.), ASCE, February, Vol. 1, pp. 1290ASCE, February, Vol. 1, pp. 1290––13041304

10/28/2009 87

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O’Neill, M. W., Vipulanandan, C., Ata, A., Tan, F. (1999). “Axial O’Neill, M. W., Vipulanandan, C., Ata, A., Tan, F. (1999). “Axial Performance of ContinuousPerformance of Continuous-- FlightFlight--Auger Piles for Bearing,” Final report Auger Piles for Bearing,” Final report to the Texas Department of Transportation, Report No. 7to the Texas Department of Transportation, Report No. 7--39403940--2, 2, August, 254 .August, 254 .O’Neill, M.W. and Reese, L.C. (1999). “Drilled Shafts: Construction O’Neill, M.W. and Reese, L.C. (1999). “Drilled Shafts: Construction Procedures and Design Methods,” FHWA Report No. IFProcedures and Design Methods,” FHWA Report No. IF--9999--025, Federal 025, Federal Highway Administration, Washington, D.C.Highway Administration, Washington, D.C.O’Neill, M.W., Vipulanandan, C., and Hassan, K. (2000). “Modeling of O’Neill, M.W., Vipulanandan, C., and Hassan, K. (2000). “Modeling of Laterally Loaded ACIP Piles in Overconsolidated Clay,” Geotechnical Laterally Loaded ACIP Piles in Overconsolidated Clay,” Geotechnical Special Publication No. 100, N. D. Dennis, R. Castelli, and M. W. O’Neill Special Publication No. 100, N. D. Dennis, R. Castelli, and M. W. O’Neill (Eds.), ASCE, August, pp. 382(Eds.), ASCE, August, pp. 382––396.396.(Eds.), ASCE, August, pp. 382(Eds.), ASCE, August, pp. 382 396.396.Reese, L. C., and O’Neill M. W. (1988). “Drilled Shaft: Construction Reese, L. C., and O’Neill M. W. (1988). “Drilled Shaft: Construction Procedures and Design Methods,” FHWAProcedures and Design Methods,” FHWA--HIHI--8888--042, Federal Highway 042, Federal Highway Administration, Washington, D.C.Administration, Washington, D.C.Viggiani, C. (1993) “Further Experiences with Auger Piles in Naples Viggiani, C. (1993) “Further Experiences with Auger Piles in Naples Area,” Proceedings of the 2nd International Geotechnical Seminar on Area,” Proceedings of the 2nd International Geotechnical Seminar on Deep Deep

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Zelada, G. A., and Stephenson, R. W. (2000). “Design Methods for Zelada, G. A., and Stephenson, R. W. (2000). “Design Methods for Auger CIP piles in Compression,” New Technological and Design Auger CIP piles in Compression,” New Technological and Design Developments in Deep Foundations, ASCE Geotechnical Special Developments in Deep Foundations, ASCE Geotechnical Special Publication No. 100, N. D. Dennis, R. Castelli and M. W. O’Neill (Eds.), Publication No. 100, N. D. Dennis, R. Castelli and M. W. O’Neill (Eds.), ASCE, August, pp. 418ASCE, August, pp. 418––432.432.

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THANK YOUTHANK YOU

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11/1/2009

1

Geotechnical Earthquake Engineeringfor the New I-70 Mississippi River Bridge

Youssef M A Hashash & Scott M Olson

University of Illinois at Urbana-Champaign 1

Youssef M. A. Hashash & Scott M. Olson

Department of Civil and Environmental Engineering

University of Illinois at Urbana-Champaign

Fall Technical Seminar

ASCE Geotechnical Group – St. Louis

October 30, 2009

AcknowledgementsAcknowledgements

• Dr. Norm Abrahamson

• Mr. Steve Hague, structural design team, and geotechnical design team, HNTB Corporation


OutlineOutline

• Background

• Site investigation

• Seismic hazard analysis & conditional mean spectrum


• Nonlinear site response analysis

• Liquefaction & seismic stability analyses

• Concluding remarks

11/1/2009

2

BackgroundBackground

• New cable-stayed structure to divert I-70 traffic north of Poplar Street bridge

• 6,460 ft of structure including Illinois approach, main span (~1500 ft navigation channel), and Missouri approach

• 23 pier locations• Main span founded


Main span founded on hydrauliccaissons

Artist’s rendering from HNTB

Earthquake ShakingEarthquake Shaking

Fault ruptureWave propagationlocal Ground motion and site effects

Permanent ground deformations: Ground FailureTsunamis & Ground FailureTransient ground deformations: site response

University of Illinois at Urbana-Champaign 6CEE 588, Lecture 01; © 2005 Y. M. A. Hashash &

Site InvestigationSite Investigation

• 42 exploratory borings at 23 pier locations

• Downhole geophysics performed at 10 boring locations

• 18 seismic piezocone penetration tests


• Index, permeability, and strength testing for soils and rock

11/1/2009

3

General Subsurface ConditionsGeneral Subsurface Conditions


Subsurface Conditions Subsurface Conditions –– Missouri approachMissouri approach


Subsurface Conditions Subsurface Conditions –– Missouri alluviumMissouri alluvium


11/1/2009

4

Subsurface Conditions Subsurface Conditions –– Illinois recent alluviumIllinois recent alluvium


Subsurface Conditions Subsurface Conditions –– Illinois Illinois glaciofluvialglaciofluvial


Subsurface Conditions Subsurface Conditions –– Limestone bedrockLimestone bedrock


11/1/2009

5

Example design profile Example design profile –– SRSR--ILIL--22


DETERMINISTIC HAZARD ANALYSIS (DHA): DETERMINISTIC HAZARD ANALYSIS (DHA): Scenario EarthquakeScenario Earthquake


PROBABILISTIC SEISMIC HAZARD ANALYSIS PROBABILISTIC SEISMIC HAZARD ANALYSIS (PSHA)(PSHA)


11/1/2009

6

Use Deaggregation to obtain M and R that has the highest contribution.

Memphis

DEAGGREGATIONDEAGGREGATION


Contribution of M= 7.5 - 8events is dominant in NMSZ

Hazard at the margins Hazard at the margins -- NMSZNMSZ


USGS

PSHA Response SpectraPSHA Response Spectra

0.4

0.5

0.6

ele

ratio

n (g

)

975UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS

5% in 50 yrs (975 yr) Hazard

0.4

0.5

0.6

ele

ratio

n (g

)

2500UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS



0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

Sp

ect

ral A

cc

0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

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ect

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cce

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DeaggregationDeaggregation--2500 2500 ((55%in %in 50 50 yrs)yrs)






11/1/2009

8

Deterministic Seismic Hazard AnalysisDeterministic Seismic Hazard AnalysisBiBi--modal hazardmodal hazard

0.4

0.5

0.6

atio

n (g

)

975UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS


0.4

0.5

0.6

atio

n (g

)

2500UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS



0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

Sp

ect

ral A

cce

lera

0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

Sp

ect

ral A

cce

lera

PSHA PSHA vsvs DSHA: Can we reconcile?DSHA: Can we reconcile?

0.4

0.5

0.6

ele

ratio

n (

g)

975UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS


0.4

0.5

0.6

ele

ratio

n (

g)

2500UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS



0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

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ectr

al A

cce

0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

Sp

ectr

al A

cce

What is Conditional Mean Spectrum What is Conditional Mean Spectrum (CMS) (CMS) slide from J. Baker Stanford Universityslide from J. Baker Stanford University


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CMS (11) slide from J. Baker Stanford University


PSHA PSHA vsvs DSHA: Can we reconcile?DSHA: Can we reconcile?

0.4

0.5

0.6

cele

ratio

n (g

)

975UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS


0.4

0.5

0.6

ele

ratio

n (g

)

2500UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS



0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

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ect

ral A

cc

0.01 0.1 1 10Period (sec)

0

0.1

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ect

ral A

cc

CMS for Mississippi River BridgeCMS for Mississippi River Bridge

0.4

0.5

0.6

cele

ratio

n (

g)

975UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS


0.4

0.5

0.6

ele

ratio

n (

g)

2500UHS

M6 84th

M6 Med

M7.5 84th

M7.5 Med

0.2sec CMS

1.0sec CMS

2% in 50 yrs (2475 yr) HazardInstead of a single UHRS use two UHRS compatible CMS:

[email protected] ~ M=6 event

[email protected] ~ M=7.5 events


0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

Sp

ectr

al A

cc

0.01 0.1 1 10Period (sec)

0

0.1

0.2

0.3

Sp

ectr

al A

cc

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Background –– 11--D Site response D Site response modelingModelingmodelingModeling

1D Wave Propagation – Time Domain SolutionNumerical Solution:

1h11 ,G

Layer1

2

G

22 21 mm

22 32 mm

21m

11 c,k

22 c,k

k

2h

h


i

n

22 ,G

ii ,G

nn ,G

3 33 ,G

EE ,G

iii hm

2nmSEEE VC nn c,k

33 c,k3h

nh

ih

Layer Properties

G: shear modulus: densityVS: shear wave velocityh: thickness

Equivalent Lumped Mass System

k: stiffnessc: viscous damping

Background –– 11--D ModelingD Modeling

1D Wave Propagation – Time Domain Solution

guIMuKuCuM

Equation of Motion:


[C]: Damping matrix → Viscous DampingRayleigh DampingExhibit frequency dependent behavior

[M]: Mass matrix → Less uncertaintyStraightforward calculation

[K]: Stiffness matrix → Nonlinearity: Recalculated in each time stepUse of simplified models (i.e. Hyperbolic Model or Ramberg Osgood)Modulus reductionHysteretic Damping

Background –– 11--D ModelingD Modeling

1D Wave Propagation – Time Domain Solution

Gsec1

Gsec2

Initial L di

Modified Extended Hyperbolic Model

smo

s

mo

mo G

G

G

11


Backbone Curve

LoadingCurve

SubsequentLoading & Unloading Curves

g

uMuKuCuM

Dynamic Equation :

rmo

11/1/2009

11

Issue 1:

Small Strain DampingSmall Strain Damping


Small Strain – Viscous - Damping

g

uMuKuCuM

Dynamic Equation :

2

Stiffness proportional damping

Rayleigh Damping

1

0

1N

b

b

b KMaMC

Small Strain DampingSmall Strain Damping


0

1

Full Rayleigh Damping

Simplified Rayleigh Damping

Extended Rayleigh

0 5 10 15 20 25 30 35Frequency (Hz)

Dam

ping

rat

io,

(%

)

Mass proportional damping

Frequency Independent

Over-damped

Under-damped

Small Strain Damping

Frequency Independent Damping Formulation to construct the damping matrix

11

021

11

0

21

0

1

N

b

N

b

bb

N

b

b

b aMaMKMaMC


n

nn

N

b

bnb

nn

a

afaf

faf

2

2

12

4

12

4

1

21

2121

1

0

2

Small strain damping independent of the frequency → experimental results

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12

Issue 2:


Large strain – hysteretic - damping

Large strain dampingLarge strain damping

0.0

0.2

0.4

0.6

0.8

1.0

0.0001 0.001 0.01 0.1 1

Shear strain - - [%]

G/G

0

MasingRules

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2

/max,cycle

/m

ax,c

ycle

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2

/max,cycle

/m

ax,c

ycle

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

-1.2 -0.8 -0.4 0.0 0.4 0.8 1.2

/max,cycle

/m

ax,c

ycle


0

5

10

15

20

25

30

35

40

0.0001 0.001 0.01 0.1 1


Dam

ping

[%

]

Test Data Calculated Value

0

5

10

15

20

25

30

35

40

0.0001 0.001 0.01 0.1 1


Dam

ping

[%

]


Shear strain [%]

B

ADampingStrainSmalltotal

4

0

5

10

15

20

25

30

35

40

0.0001 0.001 0.01 0.1 1


Dam

ping

[%

]


0

5

10

15

20

25

30

35

40

0.0001 0.001 0.01 0.1 1


Dam

ping

[%

]


0

5

10

15

20

25

30

35

40

0.0001 0.001 0.01 0.1 1


Dam

ping

[%

]


DampingMismatch

Small strain Damping

Hysteretic Damping

s

G

1

0

Load Curve

Non Masing rule criteria

1

G0

mrev

New Fm)m

Large Strain Damping (Hysteretic)Large Strain Damping (Hysteretic)


r

revs

r

m

revs

r

m

revs

r

rev

rev

m

GGG

F

112

1

22 00

0

Unload – Reload Curve

Load CurveUnload – Reload Curve

rev

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13

Non-Masing rule criteria

Use a reduction Factor MRDF:

3

1 m

pG

F

New Model

0.60

0.70

0.80

0.90

1.00on

Fac

tor

for

hyst

eret

ic D

ampi

ng

F(

) =

L

abo

rato

ry/

Mas

ing

Vucetic & Dobry 1991 -PI = 0 - Fit

Vucetic & Dobry 1991 -PI = 0 - Target

Seed & Idriss 1970 - SandMean - Fit

Seed & Idriss 1970 - SandMean - Target

Zhang et al. 2005 -Quaternary Soil PI = 0 -Fit

R2=0.99

R2=0.95

R2=0.99

R2=0.960.0

0.2

0.4

0.6

0.8

1.0

0 0001 0 001 0 01 0 1 1 10

G/G

o

0.0

0.2

0.4

0.6

0.8

1.0

0 0001 0 001 0 01 0 1 1 10

G/G

o

Large Strain Damping (Hysteretic)


1 20

1 m

mF p pG

- Free Parameters- Fitting Methodology

0.40

0.50

0.01 0.1 1 10

Shear Strain - - [%]

Red

uctio

Zhang et al. 2005 -Quaternary Soil PI = 0 -Target

Zekkos et al. 2006 - 8-25%< 20mm - Fit

Zekkos et al. 2006 - 8-25%< 20mm - Target

0.0001 0.001 0.01 0.1 1 10

0

10

20

30

40

0.0001 0.001 0.01 0.1 1 10


Dam

ping

[%

]

Sands Mean Limit - Seed & Idriss 1971Result Fitting MRDF

0.0001 0.001 0.01 0.1 1 10

0

10

20

30

40

0.0001 0.001 0.01 0.1 1 10


Dam

ping

[%

]

Sands Mean Limit - Seed & Idriss 1971Result Fitting MRDF

ImplementationImplementation

DEEPSOIL

FrequencyDomain

Time Domain

1D Site Response Analysis (e.g. DEEPSOIL)http://www.illinois.edu/~deepsoil


Linear

Equivalent Linear

Total Stress Effective Stress

Std. Hyperbolic Model (MR, MRD, MD)

New Hyperbolic Model(MRDF)

PWP ModelSand

PWP ModelClay

Linear

Non Linear

Implementation in DEEPSOILImplementation in DEEPSOIL


http://www.illinois.edu/~Deepsoil/

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Large Strain Damping (Hysteretic)

Implementation in DEEPSOILImplementation in DEEPSOIL


Fitting scheme

MR: Fitting Modulus Reduction Curve onlyMRD: Fitting Modulus Reduction and Damping Curve simultaneouslyMD: Fitting Damping Curve only MRDF: Fitting Modulus Reduction and Damping Curve simultaneously using the damping reduction factor. Non-Masing rule unload-reload criteria

V3.5 R17

60

50

40

30

20

10

0

ft)

0 500 1000 1500 2000Vs (ft/sec)

0 10 20 30 40PI

100120140160Unit weight (pcf)

0 4000 8000'vo (psf)

1 5 9 13OCR

0 500 1000 1500 2000su (psf)

alluvialmix

fine tomediumpoorly

d d

SP

alluvialmix

Typical Soil Profile Typical Soil Profile –– Illinois SideIllinois Side


140

130

120

110

100

90

80

70

De

pth

(f

Vs = 6500 ft/s

Wxlimestone

Unwxlimestone

gradedsand (SP)

Site response for deep sectionsSite response for deep sectionsIllinois Profiles, Section SR-IL-2, SR-IL-3, SR-IL-42% in 50 yrs (2475 yr) Hazard

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

al A

cce

lera

tion

(g)

2475UHS(Rock)

0.2sec CMS(Rock)

Section 9

Section 7

Section 6

5% Damped Surface Response Spectra, 0.2 sec motion site response

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

al A

cce

lera

tion

(g)

975UHS(Rock)

0.2sec CMS(Rock)

Section 9

Section 7

Section 6

5% Damped Surface Response Spectra, 0.2 sec motion site response

Higher acceleration – Lower M Lower acceleration – Higher M


0.01 0.1 1 10Period (sec)

0

0.1

0.2

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0.4

0.5Spe

ctr

0.01 0.1 1 10Period (sec)

0

0.1

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ect

ra

Implication => very limited liquefaction v.s. extensive liquefaction without CMS

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Liquefaction Analysis ApproachLiquefaction Analysis Approach

• Triggering analysis– SPT using Youd et al. (2001) and checked with

Cetin et al. (2004)

– CPT using Robertson and Wride (1998) and checked with Moss et al (2006)


checked with Moss et al. (2006)

• Lateral spreading analysis– Youd et al. (2002) and checked using Olson and

Johnson (2008) and Zhang et al. (2004)

Liquefaction Analysis ApproachLiquefaction Analysis Approach

• Liquefaction-induced settlement– SPT using Idriss and Boulanger (2008) and

checked using Tokimatsu and Seed (1987)

– CPT using Zhang et al. (2005) and checked using Ishihara et al (1992)


Ishihara et al. (1992)

• Porewater pressure generation– Estimated using Marcuson and Hynes (1990)

Liquefaction evidenceLiquefaction evidence

• Liquefaction in St. Louis related to 1811-12 earthquakes was sparse

• Nuttli (1983) “mention of sand blow activity on


of sand blow activity on floodplain

• Lateral spreading limit of about 175 km (Keefer 1984)

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16

Liquefaction evidenceLiquefaction evidence

• MMI ~ 7-8 from 1811-12 events

• Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse Damage


with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.

• Small water and sand ejections and localized lateral spreading adjacent to streams, canals, lakes, etc.

• A new concept of conditional mean spectra is introduced that bridges the gap between probabilistic and deterministic seismic hazard analysis

• Improved site response analysis procedures essential for reliable estimate of site effects

• The resulting site response and liquefaction analysis provided estimates of

ConclusionsConclusions


The resulting site response and liquefaction analysis provided estimates of ground motions and ground response that are consistent with historical evidence.

• Significant impact on engineer design

THANK YOU


THANK YOU

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