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2006 ASCE Florida Section Annual Conference
IMPLEMENTATION OF O-CELLIMPLEMENTATION OF O-CELL®® LOADLOAD TESTING FOR DRILLED SHAFTS TESTING FOR DRILLED SHAFTS
AND AND AUGERED-CAST-IN-PLACE (ACIP) AUGERED-CAST-IN-PLACE (ACIP)
PILESPILES
John HayesJohn Hayes, Senior Project Manager | LoadTest, Inc., Senior Project Manager | LoadTest, Inc.Matthew E. Meyer, P.E.Matthew E. Meyer, P.E., Senior Associate | Langan , Senior Associate | Langan Engineering and Environmental Services, Inc.Engineering and Environmental Services, Inc.
2006 ASCE Florida Section Annual Conference
IMPLEMENTATION OF O-CELL LOAD TESTING FOR IMPLEMENTATION OF O-CELL LOAD TESTING FOR DRILLED SHAFTS AND AUGERED-CAST-IN-PLACE DRILLED SHAFTS AND AUGERED-CAST-IN-PLACE
(ACIP) PILES(ACIP) PILES
• Comparison of Conventional Top Load and Comparison of Conventional Top Load and the Osterberg Cell the Osterberg Cell
• O-Cell EvolutionO-Cell Evolution• Limitations and AdvantagesLimitations and Advantages• ApplicationsApplications• Constructability IssuesConstructability Issues• ACIP piles – Necessity leads to InnovationACIP piles – Necessity leads to Innovation• ACIP MilestonesACIP Milestones• InstrumentationInstrumentation
2006 ASCE Florida Section Annual Conference
COMPARISON OF O-CELL AND COMPARISON OF O-CELL AND CONVENTIONAL TESTSCONVENTIONAL TESTS
2006 ASCE Florida Section Annual Conference
O-Cell Evolution O-Cell Evolution
Evolution of Technology from 1980’s to 2006 Evolution of Technology from 1980’s to 2006
• Pioneering research by Dr. Jorj Osterberg and Pedro Pioneering research by Dr. Jorj Osterberg and Pedro De Silva in the 1980’sDe Silva in the 1980’s
• Osterberg’s impetus - to ascertain the bearing Osterberg’s impetus - to ascertain the bearing capacity within a rock socketcapacity within a rock socket
• Mid-west US and BrazilMid-west US and Brazil• Loadtest Inc. founded in 1991Loadtest Inc. founded in 1991• O-Cells available in sizes ranging from 9” – 34” dia O-Cells available in sizes ranging from 9” – 34” dia
and loads from 200 kips to >64,000 kipsand loads from 200 kips to >64,000 kips• Multi-cell and Multi-level applicationsMulti-cell and Multi-level applications• Bi-directional testing is used globallyBi-directional testing is used globally
2006 ASCE Florida Section Annual Conference
O-cell Bi-directional TestingO-cell Bi-directional Testing
Advantages
• No external reaction system
• No anchor piles
• Little or no heavy transport requirements
• Only half the stresses applied to the concrete
• Significant cost savings as loads increase
Limitations
• Pre-selected pile
• Maximum load limited by weaker of end bearing or skin friction
• Test results need interpretation
• Top of the pile is not structurally tested
• Top load movement curve must be calculated
2006 ASCE Florida Section Annual Conference
53
33
4
10
11
10
2
13 15
10
36
319
24
1223
17
89
157515
2
12
13
4(NH) 1
(CT) 7
Total USA Tests: 677
(MA) 26
7
2
World record load test set in 2001
(PR) 29
2 Lateral
4
(HI) 34
19(NJ) 31
(MD) 8(DC) 7
(RI) 4
Osterberg Cell Tests Completed in the United States*
*As of September 30, 2005
1
World record load test set in 2003
2
2006 ASCE Florida Section Annual Conference
O-cell Tests World-wideO-cell Tests World-wide
1-1011-2021-30>30
0
Upcoming/In progress
Key
2006 ASCE Florida Section Annual Conference
3000 ton Conventional3000 ton Conventional2500 ton Conventional2500 ton Conventional
3000 ton O-cell Test3000 ton O-cell Test
No reaction system required
Advantage in many in-situ scenarios including:
off-shore•low concrete cut-offs•confined areas
2006 ASCE Florida Section Annual Conference
One Raffles Quay, SingaporeOne Raffles Quay, Singapore(with Gammon Skanska and Meinhardt consultant)(with Gammon Skanska and Meinhardt consultant)
13 tests completed during November and December 2004 – 13 tests completed during November and December 2004 – extremely difficult soil conditions (Boulderly Clay)extremely difficult soil conditions (Boulderly Clay)
2006 ASCE Florida Section Annual Conference
Foundation ApplicationsFoundation Applications
• Drilled ShaftsDrilled Shafts• ACIP PilesACIP Piles• Driven PilesDriven Piles• Slurry Walls/BarrettesSlurry Walls/Barrettes
2006 ASCE Florida Section Annual Conference
Installation Schematics for Drilled Installation Schematics for Drilled Shafts in South FloridaShafts in South Florida
2006 ASCE Florida Section Annual Conference
Connection of O-Cell to Drilled Connection of O-Cell to Drilled ShaftShaft
2006 ASCE Florida Section Annual Conference
Drilled Shaft O-Cell and Reinforcing CageDrilled Shaft O-Cell and Reinforcing Cage
2006 ASCE Florida Section Annual Conference
THE MULTI-LEVEL O-CELL TEST CAN PROVIDE THE ENGINEER WITH MORE INFORMATION WHEN THE ESTIMATED CAPACITY IN SIDE SHEAR EXCEEDS THAT OF END BEARING
THE TEST ALLOWS THE ENGINEER TO OBTAIN DATA ON THREE OR MORE ISOLATED PILE COMPONENTS (i.e. two or more for shear and one for end bearing)
MULTI-LEVEL O-CELLMULTI-LEVEL O-CELLLOAD TESTINGLOAD TESTING
2006 ASCE Florida Section Annual Conference
2006 ASCE Florida Section Annual Conference
Multi Level O-cell Shaft Installation
2006 ASCE Florida Section Annual Conference
Constructability Issues For O-Cell Constructability Issues For O-Cell Installation in Drilled ShaftsInstallation in Drilled Shafts
• O-Cell diameter to shaft diameterO-Cell diameter to shaft diameter• O-Cell positions and tremie pipe positionO-Cell positions and tremie pipe position• Concrete slump and slump loss vs. timeConcrete slump and slump loss vs. time• Concrete cover on reinforcing cageConcrete cover on reinforcing cage• Spacing between vertical and horizontal Spacing between vertical and horizontal
reinforcing steelreinforcing steel• Horizontal assembly and cage liftingHorizontal assembly and cage lifting
2006 ASCE Florida Section Annual Conference
World-Record Drilled Shaft Load World-Record Drilled Shaft Load Test – 62,700 kipsTest – 62,700 kips
… record static load test achieving 62,700 kips (278 MN) on a single 118-inch (3m) diameter foundation pile at the Incheon 2nd Link project in Korea…
2006 ASCE Florida Section Annual Conference
O-Cell Development to ACIP Pile O-Cell Development to ACIP Pile Construction TechniqueConstruction Technique
Necessity is the Mother of InventionNecessity is the Mother of Invention-Plato-Plato
Necessity:Necessity:• To economize the testing of ever increasing ACIP pile depth and diameter To economize the testing of ever increasing ACIP pile depth and diameter
• As pile design load increases, testing becomes more costlyAs pile design load increases, testing becomes more costly• O-cell does not require reaction system, no need to drill reaction pilesO-cell does not require reaction system, no need to drill reaction piles• 2,000 kip load test from the surface becomes difficult – e.g. - 2,000 kip load cells are 2,000 kip load test from the surface becomes difficult – e.g. - 2,000 kip load cells are
not readily availablenot readily available• Shorten time for testing – 3x design allows quick test ASTM 4311D standardShorten time for testing – 3x design allows quick test ASTM 4311D standard
Issues Faced:Issues Faced:
• Insertion of reinforcing steel through grouted shaft with O-cell attachedInsertion of reinforcing steel through grouted shaft with O-cell attached• Grout fluidityGrout fluidity• Sufficient cage weightSufficient cage weight• Acceptable O-Cell/ACIP pile diameter ratio – would 50% of available volume be the limit?Acceptable O-Cell/ACIP pile diameter ratio – would 50% of available volume be the limit?• Vertical vs. horizontal assembly (cage bending/racking)Vertical vs. horizontal assembly (cage bending/racking)• Early recognition that entire assembly had to be as straight as possibleEarly recognition that entire assembly had to be as straight as possible• O-Cell to reinforcing cage connection (steel fins vs. traditional plates) O-Cell to reinforcing cage connection (steel fins vs. traditional plates) • Augercast contractors would not change installation technique to suit our method – time Augercast contractors would not change installation technique to suit our method – time
consuming, inefficient (e.g. - more than one crane)consuming, inefficient (e.g. - more than one crane)• InnovateInnovate
2006 ASCE Florida Section Annual Conference
Initial ACIP Pile ApplicationsInitial ACIP Pile Applications
Initial applicationsInitial applications• 24-inch-diameter, 100-ft long piles24-inch-diameter, 100-ft long piles
• 13-inch diameter O-cell13-inch diameter O-cell• 2,600 kips (Equivalent Top Load)2,600 kips (Equivalent Top Load)
• 30-inch-diameter, 120-ft long piles30-inch-diameter, 120-ft long piles• 16-inch diameter O-cell16-inch diameter O-cell• 4,240 kips (Equivalent Top Load)4,240 kips (Equivalent Top Load)
2006 ASCE Florida Section Annual Conference
Simulation PilesSimulation Piles
2006 ASCE Florida Section Annual Conference
Auger cast-in-place (ACIP) pilesAuger cast-in-place (ACIP) piles
Adapting to the Augercast Installation method – or making hockey sticks!
2006 ASCE Florida Section Annual Conference
Vertical Vertical AssemblyAssembly
Allowed Allowed cage to flex cage to flex assuring assuring verticality verticality (no hockey (no hockey sticks) sticks)
Welding Welding time time infringing on infringing on installation installation processprocess
Required Required a pilot hole a pilot hole for stingerfor stinger
2006 ASCE Florida Section Annual Conference
Innovate - PrefabricationInnovate - Prefabrication
• O-cells and stingers are MIG O-cells and stingers are MIG welded in shop and then shipped welded in shop and then shipped to fieldto field
• ““Fins” replace bearing plates - Fins” replace bearing plates - additional planes to attach rebaradditional planes to attach rebar
• Field welding now limited to upper Field welding now limited to upper cagecage
2006 ASCE Florida Section Annual Conference
Additional ModificationsAdditional Modifications
• Plumbers union for TT pipePlumbers union for TT pipe• Taping pipe jointsTaping pipe joints• Sealing of hose joints with Sealing of hose joints with
plumbers puttyplumbers putty
Connection of O-Cell to ACIP Piles
2006 ASCE Florida Section Annual Conference
Installation Schematics for ACIP Installation Schematics for ACIP Piles Piles
2006 ASCE Florida Section Annual Conference
Evolution of ACIP Pile ApplicationsEvolution of ACIP Pile Applications
ApplicationsApplications• 18-inch-diameter, 80-ft long piles18-inch-diameter, 80-ft long piles
• 9-inch diameter O-cell (800 kip cap.)9-inch diameter O-cell (800 kip cap.)
• 24-inch-diameter, 100-ft long piles24-inch-diameter, 100-ft long piles• 16-inch diameter O-cell (2800 kip cap.)16-inch diameter O-cell (2800 kip cap.)
• 30-inch-diameter, 120-ft long piles30-inch-diameter, 120-ft long piles• 21-inch diameter O-cell (4800 kip cap.)21-inch diameter O-cell (4800 kip cap.)
• 36-inch-diameter, 120-ft long piles36-inch-diameter, 120-ft long piles• Multi-level assembliesMulti-level assemblies• Two 21-inch diameter O-cellTwo 21-inch diameter O-cell• 26-inch? (7200 kip cap.)26-inch? (7200 kip cap.)
2006 ASCE Florida Section Annual Conference
Milestones of utilizing O-cell Milestones of utilizing O-cell Technology in Augercast pilesTechnology in Augercast piles
• Incremental records of total load on an ACIP pile – from Incremental records of total load on an ACIP pile – from 2,400 kips to >10,000 kips2,400 kips to >10,000 kips
• Increased O-Cell/shaft diameter ratio from 0.53 to 0.70Increased O-Cell/shaft diameter ratio from 0.53 to 0.70• First multi-level test on an ACIP pile (able to separate First multi-level test on an ACIP pile (able to separate
strata)strata)• Testing some of the deepest ACIP piles worldwide - >145 Testing some of the deepest ACIP piles worldwide - >145
ft. (44 m)ft. (44 m)• Method allows economical testing at 3 times design, Method allows economical testing at 3 times design,
allowing “quick test” standard.allowing “quick test” standard.• Largest known total load applied to an ACIP pile - 10,421 Largest known total load applied to an ACIP pile - 10,421
kipskips
2006 ASCE Florida Section Annual Conference
ACIP Pile O-Cell and Reinforcing ACIP Pile O-Cell and Reinforcing CageCage
2006 ASCE Florida Section Annual Conference
Multi-level Multi-level O-cell O-cell ACIP ACIP
placementplacement
2006 ASCE Florida Section Annual Conference
Schematic of Schematic of InstrumentationInstrumentation• Dial gauges for top of Dial gauges for top of
shaft deflectionshaft deflection• Strain gauges for load Strain gauges for load
distributiondistribution• Top of cell telltales for Top of cell telltales for
compressioncompression• Bottom “fin” tell-tales Bottom “fin” tell-tales
for downward for downward movement and/or O-cell movement and/or O-cell expansionexpansion
• ECT’s at tip of stinger to ECT’s at tip of stinger to measure toe movement measure toe movement
2006 ASCE Florida Section Annual Conference
O-cell O-cell Test Set upTest Set up
2006 ASCE Florida Section Annual Conference
Implementation of O-Cell Load Testing Implementation of O-Cell Load Testing for Drilled Shafts and Augered Cast-in-for Drilled Shafts and Augered Cast-in-
Place (ACIP) PilesPlace (ACIP) Piles• Drilled shaft load test resultsDrilled shaft load test results• ACIP pile load test resultsACIP pile load test results• Top load test results vs. calculated equivalent top load Top load test results vs. calculated equivalent top load
curvescurves• Load DistributionLoad Distribution• Mobilized side shear for drilled shaftsMobilized side shear for drilled shafts• Mobilized end bearing for drilled shaftsMobilized end bearing for drilled shafts• Strain gauge interpretation (drilled shafts and ACIP Strain gauge interpretation (drilled shafts and ACIP
piles)piles)• Testing DevicesTesting Devices• O-Cell positionsO-Cell positions• Regional ApplicationsRegional Applications
2006 ASCE Florida Section Annual Conference
Result of Bi-Directional Load Test:Result of Bi-Directional Load Test:Drilled ShaftsDrilled Shafts
2006 ASCE Florida Section Annual Conference
Result of Bi-Directional Load Test:Result of Bi-Directional Load Test:Auger Cast-In-Place (ACIP) PilesAuger Cast-In-Place (ACIP) Piles
2006 ASCE Florida Section Annual Conference
Top Load Test: Top Load Test: Predicted vs. Field ResultsPredicted vs. Field Results
2006 ASCE Florida Section Annual Conference
Top Load Test Setup:Top Load Test Setup:30-Inch-Diameter ACIP PILE30-Inch-Diameter ACIP PILE
2006 ASCE Florida Section Annual Conference
Load Distribution for ACIP Piles:Load Distribution for ACIP Piles:O-Cell Load TestsO-Cell Load Tests
2006 ASCE Florida Section Annual Conference
Load Distribution for ACIP PilesLoad Distribution for ACIP PilesTop Load TestsTop Load Tests
2006 ASCE Florida Section Annual Conference
Mobilized Side ShearMobilized Side ShearDrilled ShaftsDrilled Shafts
2006 ASCE Florida Section Annual Conference
Mobilized End BearingMobilized End BearingDrilled ShaftsDrilled Shafts
2006 ASCE Florida Section Annual Conference
Geotechnical Considerations for Geotechnical Considerations for Strain Gauge InterpretationStrain Gauge Interpretation
• Shaft diameterShaft diameter• Shaft roughness/undulationsShaft roughness/undulations• Slurry exposure (filtercake)Slurry exposure (filtercake)• Drilling procedure and casing extraction Drilling procedure and casing extraction
procedureprocedure• Pile diameterPile diameter• Pile undulationsPile undulations• Conditions at test shaft/pile location vs. Conditions at test shaft/pile location vs.
site subsurface conditionssite subsurface conditions
2006 ASCE Florida Section Annual Conference
Shaft CaliperShaft Caliper
2006 ASCE Florida Section Annual Conference
Shaft DiameterShaft DiameterShaft Caliper Sample Test ResultsShaft Caliper Sample Test Results
2006 ASCE Florida Section Annual Conference
Shaft Diameter 3-D RenderingShaft Diameter 3-D Rendering
2006 ASCE Florida Section Annual Conference
Shaft Sampling and Inspection Tools:Shaft Sampling and Inspection Tools:Sidewall SamplerSidewall Sampler
2006 ASCE Florida Section Annual Conference
Shaft Sampling and Inspection Shaft Sampling and Inspection Tools: Mini-SIDTools: Mini-SID
2006 ASCE Florida Section Annual Conference
Caliper Results from ACIP PileCaliper Results from ACIP Pile
• No technique presently available to No technique presently available to determine diameter versus depth of determine diameter versus depth of ACIP pileACIP pile
• Inferences available based on grout Inferences available based on grout factorfactor
2006 ASCE Florida Section Annual Conference
O-Cell Positioning ConsiderationsO-Cell Positioning Considerations
• Reaction above and below O-Cell is Reaction above and below O-Cell is necessary to facilitate testingnecessary to facilitate testing
• Proper positioning to evaluate single Proper positioning to evaluate single or multiple bearing layersor multiple bearing layers
• Proper positioning to evaluate end Proper positioning to evaluate end bearing alone or through bearing alone or through instrumentationinstrumentation
2006 ASCE Florida Section Annual Conference
Typical Application in South FloridaTypical Application in South Florida
2006 ASCE Florida Section Annual Conference
Typical Application in Northern Typical Application in Northern FloridaFlorida
2006 ASCE Florida Section Annual Conference
Typical Application in Western Typical Application in Western FloridaFlorida
2006 ASCE Florida Section Annual Conference
ConclusionsConclusions
• Full-scale load testing of production sized Full-scale load testing of production sized foundation elements is viablefoundation elements is viable
• Can separate shaft capacity into Can separate shaft capacity into componentscomponents
• Understanding of load distribution with Understanding of load distribution with depth and available side shear with depthdepth and available side shear with depth
• Can obtain end bearing values at various Can obtain end bearing values at various deflectionsdeflections
• Adaptation of existing technology has Adaptation of existing technology has allowed ACIP piles to be O-Cell load testedallowed ACIP piles to be O-Cell load tested