ODOT- PIT and CSL Overview

7/25/2019 ODOT- PIT and CSL Overview

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GRLGRLDynamic Testing Methods for

Evaluation of Integrity andCapacity for Drilled Shafts

Dynamic Testing Methods for

Evaluation of Integrity andCapacity for Drilled Shafts

CSL

CSL

PDAPDAPDA PITPITPIT


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GRLGRLDeep Foundation Solutions:

Driven Piles

Steel, Concrete, Timber

Drilled Shafts Wet or Dry, Cased or Uncased

Augercast Piles

Each pile type has differentinspection needs

Deep Foundation Solutions:Deep Foundation Solutions:

Driven PilesDriven Piles

Steel, Concrete, Timber Steel, Concrete, Timber

Drilled ShaftsDrilled Shafts Wet or Dry, Cased orWet or Dry, Cased or UncasedUncased

AugercastAugercast PilesPiles

Each pile type has differentEach pile type has differentinspection needsinspection needs


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Planned inspection

Included in project specifications

Planned costs - normal pay item

Unplanned inspection

in response to something gone wrong

Unplanned costs - who pays?

Delays project, extra claims

Planned inspectionPlanned inspection

Included in project specificationsIncluded in project specifications

Planned costsPlanned costs -- normal pay itemnormal pay item

Unplanned inspectionUnplanned inspection

in response to something gone wrongin response to something gone wrong

Unplanned costsUnplanned costs -- who pays?who pays?

Delays project, extra claimsDelays project, extra claims

( Preferred )( Preferred )( Preferred )


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Low Strain Integrity MethodsLow Strain Integrity MethodsLow Strain Integrity Methods

PILE INTEGRITY TESTING (PIT) Measure Pile Top Motion, Reflections from Defects For concrete piles, concrete filled pipes, drilled

shafts, augercast piles, and sometimes timber piles.

CROSS-HOLE SONIC LOGGING (CSL) Determines Concrete Quality Between Tubes in Shaft For drilled shafts and larger augercast piles

PILE INTEGRITY TESTING (PIT)PILE INTEGRITY TESTING (PIT) Measure Pile Top Motion, Reflections from DefectsMeasure Pile Top Motion, Reflections from Defects For concrete piles, concrete filled pipes, drilledFor concrete piles, concrete filled pipes, drilled

shafts,shafts, augercastaugercast piles, and sometimes timber piles.piles, and sometimes timber piles.

CROSSCROSS --HOLE SONIC LOGGING (CSL)HOLE SONIC LOGGING (CSL) Determines Concrete Quality Between Tubes in ShaftDetermines Concrete Quality Between Tubes in Shaft For drilled shafts and largerFor drilled shafts and larger augercastaugercast pilespiles


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GRLGRLPile Integrity Testing...

looks for major defects

Pile Integrity Testing...

looks for

major defectsSmall hammerimpact device Accelerometer

measures response

(defect)

ASTM D5882ASTM D5882


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GRLGRL

Local Defect: small medium large

Local Bulge: small medium large

PIT - Basic InterpretationsPITPIT -- Basic InterpretationsBasic Interpretations


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GRLGRLNormal test

(pile top free)

800 mm drilled shafts800 mm drilled shafts

L = 25 m (L/D = 31)L = 25 m (L/D = 31)

Good PileGood Pile

Bad PileBad Pile


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14 inch14 inch augercastaugercast pile with 15 foot rebars.pile with 15 foot rebars.

Failed static load testFailed static load test often prompts testing.often prompts testing.

Defect in this test pile shaft caused failed testDefect in this test pile shaft caused failed test(rather than soil failure)(rather than soil failure)

GRL#994034

Test Pile

DefectDefect


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GRLGRLPIT detected bored pile defect at 4.1 m depth;PIT detected bored pile defect at 4.1 m depth;confirmed by coreconfirmed by core


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Good pile with local bulgeat about 25 ft and clear toe

Bulge- / + cycle

Bad pile with major defect atabout 3.5 ft and no clear toe

Neck+ / - cycleBad pile excavatedto reveal neck


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GRLGRLClassifications(4 categories proposed by GRL)

Classifications(4 categories proposed by GRL)

AA -- Good PileGood PileClear toe response, no obvious defect; sound shaftClear toe response, no obvious defect; sound shaft

BB -- Bad PileBad PileClear identification of serious defect;Clear identification of serious defect; no toe signalno toe signal

needs contingency tests or corrective measuresneeds contingency tests or corrective measures CC -- Possible DefectPossible Defect

rere --test, other tests, reduce capacity or replacetest, other tests, reduce capacity or replace

DD -- Inconclusive dataInconclusive data(poor pile top quality,(poor pile top quality,

or no reflections due to strong soil)or no reflections due to strong soil) fix pile top & refix pile top & re --test; might givetest; might give infoinfo for upper pile shaftfor upper pile shaft

which is reason to accept pile.which is reason to accept pile.


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Compare with other observationsCompare with other observations

ReRe --test with PIT (trim pile top to solid concrete)test with PIT (trim pile top to solid concrete) Excavate if near topExcavate if near top

Request pile coreRequest pile core Request a PDA test or a static testRequest a PDA test or a static test Replace pile (or repair)Replace pile (or repair) Other?Other?

Have a planHave a plan what to do if find a defectwhat to do if find a defect

What to do if find a problem ?What to do if find a problem ?


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Some studies suggest a 30 L/DSome studies suggest a 30 L/D limit.limit.Actually this is only a rule of thumb andActually this is only a rule of thumb anduseable length depends on:useable length depends on:

soil strength,soil strength, pile uniformity,pile uniformity,

actual diameter and length,actual diameter and length, and equipment noise and resolution.and equipment noise and resolution.

We often see much farther We often see much farther

PIT LimitationsPIT Limitations

Highly nonHighly non --uniform piles difficult to interpretuniform piles difficult to interpret Cracks or mechanical joints block wavesCracks or mechanical joints block waves

Small defects (or of short length) hard to findSmall defects (or of short length) hard to find Gradual changes hard to findGradual changes hard to find


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GRLGRLPIT ConclusionsPIT ConclusionsPIT Conclusions

PIT finds major defects,

low cost so can test every pile Inclusion of inspection requirements in

job specifications is suggested PIT can sometimes test piles in structure

Guideline of use till 30 L/D is not a limit.

Cracks or gaps limit transmission of wave

No information about capacity

PIT findsPIT finds major defectsmajor defects ,,

low cost so can test every pilelow cost so can test every pile Inclusion of inspection requirements inInclusion of inspection requirements in

job specifications is suggested job specifications is suggested PIT can sometimes test piles in structurePIT can sometimes test piles in structure

Guideline of use till 30 L/D is not a limit.Guideline of use till 30 L/D is not a limit.

Cracks or gaps limit transmission of waveCracks or gaps limit transmission of wave

No information about capacityNo information about capacity


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Stress Waves, emittedStress Waves, emittedin one tube are receivedin one tube are received

in another one if concretein another one if concrete

quality is satisfactoryquality is satisfactory

ReceiveReceiveTransmit Transmit

Cross Hole Sonic Logging

ASTM D6760

Cross Hole Sonic LoggingCross Hole Sonic Logging

ASTM D6760ASTM D6760


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SignalSignal

(wave speed) = ( tube distance ) / (arrival time )(wave speed) = ( tube distance ) / (arrival time )

Arrival

Energy


Arrival

Arrival


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DefectDefect

DefectDefect

DefectDefect

How do we spot defects?How do we spot defects?Low energyLow energyLate arrivalsLate arrivals



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GRLGRL48 shaft with soft toe condition48 shaft with soft toe condition


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GRLGRLShaft with tremie defect


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insensitive to surrounding soil or pile lengthinsensitive to surrounding soil or pile length

finds multiple defects, depth and quadrantfinds multiple defects, depth and quadrant

finds soft bottoms if tubes go to bottomfinds soft bottoms if tubes go to bottom inspires careful construction by contractor inspires careful construction by contractor

CSL Testing AdvantagesCSL Testing Advantages


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must plan and install access tubesmust plan and install access tubes tubes preferably less than 2 meters aparttubes preferably less than 2 meters apart

evaluates concrete only between tube pairsevaluates concrete only between tube pairs

defects undetected when outside cagedefects undetected when outside cage

CSL Testing LimitationsCSL Testing Limitations


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GRLGRLCSL ConclusionsCSL ConclusionsCSL Conclusions Can find multiple defects and their quadrant;

not sensitive to pile length or soil

CSL finds defects between (steel) access tubes;consider defect remedy in advance

CSL access tubes in every shaft inspireshigh quality installation for every shaft

(even if do not test every shaft)

Allows low cost testing access if problems occurduring installation

Waterfall, FAT and energy complimentinterpretation of results

Can find multiple defects and their quadrant;Can find multiple defects and their quadrant;not sensitive to pile length or soil not sensitive to pile length or soil

CSL finds defects between (steel) access tubes;CSL finds defects between (steel) access tubes;consider defect remedy in advanceconsider defect remedy in advance

CSL access tubesCSL access tubes in every shaft in every shaft inspiresinspireshigh quality installation for every shafthigh quality installation for every shaft

(even if do not test every shaft)(even if do not test every shaft)

Allows low cost testing access if problems occur Allows low cost testing access if problems occurduring installationduring installation

Waterfall, FAT and energy complimentWaterfall, FAT and energy complimentinterpretation of resultsinterpretation of results


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The ndhe nd

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ODOT- PIT and CSL Overview