Grouting Piscsalko PPT

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9.0: Inspection

INTRODUCTION

• ACIP pile trends:

– Larger diameter

– Greater lengths

– Higher capacities

• Quality control and inspection is critical

• DFI is proactive in developing quality control guidelines

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INTRODUCTION

DFI References:

• ACIP Pile Manual, Second Edition (2003)

• Inspector’s guide to ACIP Piles (2010)

• ACIP Pile Specialty Seminar Proceedings (1997,1998, 2000 – 2008)

• ACIP Pile Installation Video (1998)

INTRODUCTION

DFI References:

• Inspector’s Guide to ACIP Piles Video (2001)

• Inspector’s Guide and Video on CD Rom (2001)

• Guide for Interpretation of Nondestructive Integrity Testing of ACIP and DD Piles (2011)

• Additional reference:

–FHWA GEC no. 8

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9.1: Manual Pile Inspection

PREPARATION

Before arriving to the site obtain and review…

• Geotechnical Report

• Pile Plans and Specifications

• DFI References:– ACIP Pile Manual

– ACIP Pile Specialty Seminar Proceedings

– ACIP Pile Inspection Video

– Inspector’s Guide and Video on CD‐ ROM

• Contractor’s Submittals

• Personal / Safety Equipment

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PREPARATION

Pre‐Construction Meeting• Who should attend?

– Geotechnical Engineer

– Inspector

– General Contractor

– Piling Contractor

– Testing Agency

• Discuss inspection procedures

• Review pile construction procedure / Sequence of installation

• Discuss chain of command

• Review specified augering termination criteria

• Discuss dispute resolution

PREPARATION

Grout Sampling• Mix design / Product Submittal

• Inspection Items

• Document water or admixtures added in field

• Sample frequency and number of samples

• Cubes or Cylinders

• Sample curing and handling

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PREPARATION

Once at the site, check in with the contractor, then…

• Check auger length and diameter

• Verify pile leads are clearly marked

• Check auger bit configuration

• Document equipment

• Verify grout pressure gage is functional and within view when pump stroke counting is performed

• Verify grout pump stroke counter is operational

• Check grout hopper screen

• Measure steel reinforcement and centralizers

• If AME is being used, understand the system and printout

Deep Foundations Institute “Augered Cast‐In‐Place Piles Manual” (©2003)

Section 2.2.2 “The grout pump shall be calibrated at the beginning of the work to determine the volume of grout pumped per stroke, and should be periodically recalibrated when deemed necessary by the Inspector during the project.”

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PREPARATION

Observe the pump calibration

– Container of known volume

– Count number of strokes to fill container

– Measure grout height in container

– Calculate the stroke volume:

Volume = [ ∏d²/4 ] x hd = Diameter of container (feet)

h = height of grout in container (feet)

PUMP CAL = Volume/number of strokes (ft3/stroke)

Normal grout pressure

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19

37

55

73

91

109

127

145

163

181

199

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235

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289

307

325

343

361

379

397

415

433

451

469

487

505

pre

ssu

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si .

Grout line Pressure versus Time

(fairly uniform & consistent)

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Missing stroke

Single missing pump stroke

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2501 21 41 61 81 101

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141

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UNSTABLE PUMP OPERATION

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1 23 45 67 89 111

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331

353

375

397

419

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463

485

507

529

551

573

595

617

639

661

683

Many Missing Strokes

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Section 1.5.2a “Records shall be kept for each pile installed. Such records shall as a minimum, include: project name and number, Pile Contractor, pile location and design pile capacity, pile diameter, tip elevation, drilling ground surface elevation, total and incremental volume of grout placed, amount of water (if any) added to the ready mix grout truck at the job site, pile reinforcing steel, and any unusual occurrences during the pile installation.”


Section 1.3 commentary “The grout volume placed for each increment of depth is the single most important installation control used during ACIP pile construction.”

• It is difficult to get an accurate measure of the incremental grout volume when manually inspecting

• Be certain that the incremental grout volume is being observed and accurately reported (not just total pile volume) for all piles as this is the single most important control used during ACIP pile construction

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AUGERING THE PILE

For both ACIP and DD piles…

• Know Location

• Confirm bottom plug placed

• Check auger verticality

• Time drilling progression

• Observe adjacent completed piles

• Document obstructions and unusual subsurface conditions

• Augering termination criteria:– Refusal criteria

– Embedment criteria

For ACIP piles…

• Prolonged drilling undesirable

• Rapid auger rotation undesirable

For DD piles…

• Work from inside the group towards the outside

PILE GROUTING / CONCRETING

• ACIP Piles:– Initial Grout Head– Continuous clockwise auger rotation– Incremental grout volume (calculated from manually counted pump strokes/ increment)

– Slurry/Grout Return Depth– Overall Grout Factors

• Typical ACIP Pile Values:– Porous Limestone: 1.3 to 2.0– Clean Sands: 1.3 to 1.5– Stiff Clay: 1.15 to 1.3– Soft Clay: 1.3 to 2.0– Peat: 2.0 to 3.0

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PILE GROUTING / CONCRETING

• DD Piles:

– Initial head / pressure

– Maintained head / pressure during withdrawal

– Overall grout factors:

• Typically 1.1 to 1.2

REINFORCEMENT INSTALLATION

• Confirm top of pile is free of auger spoil

• Confirm reinforcing is clean prior to insertion

• Document reinforcement installation, and any difficulties

• Confirm reinforcement settles to the specified level under its own weight

• Confirm reinforcing has specified extension above proposed cut‐off elevation

• The most cost effective and time saving remedial measure is to re‐drill and re‐grout the pile should suspect conditions be

observed

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Reports / Documentation

• The following should be documented on each pile installation record:– Project name/client– Weather conditions and temperature– Date piles placed– Pile Inspector’s name– Grout truck number, arrival time on site, batch time, grout ticket number, batch volume and amount of water added to the truck on site

– Grout sampling time and time of initial set– Grout cube sets made by the Inspector and Contractor


• The following should be documented on each pile installation record:– Flow cone orifice diameter and test results

– Measured auger diameter

– Reference elevation for pile length

– Crane lead alignment (battered or vertical)

– Time period for drilling of pile

– Abnormal drilling behavior

– Pile drilled length/pile tip and top elevation

– Theoretical pile volume

– Time period for grouting of pile

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• The following should be documented on each pile installation record:– Range in pressure during grouting

– Grout return depth

– Incremental grout volume

– Total number of pump strokes to complete pile

– Overall grout factor (actual grout volume pumped divided by theoretical grout volume)

– Any re‐augering/re‐grouting during the pile installation

– Reinforcing steel installed in the pile

– Special remarks (e.g. time of and reason for interruptions during grouting)

SAMPLE FIELD LOG

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10.0 : Automated Monitoring Equipment

Why Automated Inspection?

• Manual inspection is difficult for determining incremental grout volume

– Hard to accurately determine grout pumped versus depth increment, and in some cases this may result in measurement of overall volume only

• The pump does not always maintain a repeatable volume per pump stroke

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Why Automated Inspection?

• Missing strokes are often clustered together, so these pile

sections may be seriously under pumped– AME with magnetic flow meter measures grout volume independent

of the pump

• Leads may not be marked accurately and can not be read with great precision due to parallax

• Manually inspected Incremental grout volume is typically recorded every 5 feet with low precision– AME can do better (recommend 2 ft. recording)

Goals for automated inspection:

• Provide information to help installation

• Document pumped volume versus depth

– to ensure sufficient pumping vs depth

• Easy to use, minimum input needed

• Operated by existing site personnel

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• AME produces :

– Real time graph to guide the operator

• Displays incremental grout volume in user selectable increments

– Field printout immediately after pile completion

– Digital record

• Data is saved for every 1 inch of pile length

Automated Monitoring Equipment (AME)

• Equipment automatically monitors, displays in real time and digitally records key drillingelements:

– Time

– Depth

– Torque Pressure

– Auger Rotation


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• Equipment automatically monitors, displays in real time and digitally records key groutingelements:

– Time

– Depth

– Grout Volume

– Grout Line Pressure

– Auger Rotation


Automated Monitoring System Components

• Depth Sensor measures auger tip position

• Magnetic Flow Meter measures incremental grout volume

• Pressure sensor measures grout line pressure

• Pressure sensor measures auger torque

• Control unit measures, records, and displays drilling and grouting data

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Pile Installation Recorder for Auger Cast Piles

1. Main Controller2. Depth Reel3. Grout line Pressure4. Magnetic Flow Meter5. Torque Pressure6. Auger Rotation

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1 44

2

3

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Automated Monitoring Systems Pile Dynamics PIR‐A System

AME readout guides crane operator to more uniform pile

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PIR Grouting Screen

Increments with low grout appear as red to

alert operator

PIR Viewer

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Automated Monitoring Systems Pile Dynamics PIR System

The Deep Foundations Institute’s Cast‐in‐Place Piling Seminar‐ KC '09

• Magnetic flow meters create a magnetic field in the tube.

• Faraday's Law of Induction: "a conductive medium moving through a magnetic field will induce a voltage in the medium that is proportional to its average flow velocity."

• This measurement depends only on conductivity and is independent of density, viscosity, or any other parameter.

Magnetic Flow Meter

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Field Printout

• Pile Name: 16REV

• Project Name: PITTSBURGH

• Pile Vol: 72.25 ft3 (139%)

• Date: 2009‐07‐08

•

• Auger Data [start 16:05]

• time torque‐pres

• depth interval min max

• (ft) (sec) (PSI)

• 0.0

• 2.0 21 158 247

• 4.0 19 240 400

• 6.0 20 273 352

• 34.0 51 833 1558

• 36.0 73 1003 1570

• 37.2 97 968 1227

• [ 37.1, 0.0] [stop 16:22 (00:10:41)]

• Pile name, Project name, volume in shaft, and date of installation

• Depth, printed in user defined increments

• Time for each depth increment printed

• Minimum and maximum torque as a function of depth

• Start time• Stop time as well as total

drilling time

Field Printout• Maximum Drilling Depth

• Volume Required to fill Auger stem plus Starting Head

• Depth printed in User defined Increments

• Withdrawal time as a function of depth

• Pumped Volume as a function of depth

• Pumped Volume Ratio (Pumped Volume/Nominal Volume) as a function of Depth

• Min and Max Grout Line Pressure

• Grout Return Depth

• Start/Stop Times

• Withdrawal Data [start 16:22]

• pumped volume line

• depth dT volume ratio min max

• (ft) (sec) (ft3) (%) (PSI)

• 37.2 (max depth)

• 36.9 6.50 (Stem+Head)

• 36.0 24 4.31 261 114 229

• 34.0 7 5.97 211 211 245

• 32.0 6 3.71 131 224 255

• 16.0 6 4.03 143 186 212

• 15.9 <‐‐ return depth (‐0.9)

• 14.0 6 3.92 139 187 211

• 12.0 5 3.00 106 184 212

• 2.0 6 3.60 127 174 201

• 0.0 9 3.07 109 171 198

• 1.84 (spill vol)

• [stop 16:24 (00:02:15)]

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Field Printout

• Nominal Incremental Volume• Target Incremental Volume• Nominal Pile Volume• Pile Target Volume• Volume Pumped into Pile• Stem Volume• Starting Head Volume• Spill Volume• Reaugered Volume• Grout Return Height

• Volume: (ft3)• Nominal Inc: 2.83 (2.0 ft)• Target Inc: 3.25 (2.0 ft)• Nominal: 51.91 (16.0 in dia)• Min Target: 59.70 (115%)• Shaft: 72.25 (139%)• Stem: 3.67• Head: 2.83 (2.0 ft)• Pile: 78.75 (152%)• Spill: 1.84• Reaugered: 0.00• Total: 80.59• Return: 44.21 (85%)•• Pile = Shaft + Stem + Head• Total = Pile + Spill + Reauger•• Legend for Increment Warnings.• * pumped volume < target volume• ** pumped volume < nominal volume•

PIR Volume Rate and Withdrawal Rate vs. Time

Volume Rate and Withdrawal Rate vs. Time

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0.00.51.01.52.02.53.03.54.04.5

Time (min)

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Vol. Rate

Withdrawl RateWithdrawal Rate Slows as Volume Rate Slows

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Volume Rate and Pump Pressure vs. Time

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00.511.522.533.544.5

Time (min)

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Pumped Volume Rate is low during times of pump

malfunctions.

Volume and Withdrawal Rate vs. Auger Depth

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Depth (ft)

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Withdrawl Rate

Normalized Volume

Theoretical Volume (100%)

Even with pump malfunction, by monitoring with PIR, the pile was installed with

adequate incremental volume versus depth.

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10.1 Properly Using AME

PIR Field Printout with 5 foot increment Setting

• Shaft Name: 1093

• Project Name: TEST

• Pile Vol: 107.18 ft3 (116%)

• Date: 2008‐07‐22

•

• Auger Data [start 11:45]

• time torque‐pres

• depth interval min max

• (ft) (sec) (PSI)

• 0.0

• 5.0 151 0 0

• 10.0 33 0 0

• 15.0 38 0 0

• 20.0 33 0 0

• 25.0 33 0 0

• 30.0 34 0 0

• 35.0 34 0 0

• 40.0 34 0 0

• 45.0 34 0 0

• 50.0 34 0 0

• 52.3 16 0 0

• [stop 11:54 (00:07:55)]


• pumped volume pump line_pres

• depth volume ratio strks min max

• (ft) (ft3) (%) (PSI)


• 51.8 1.84 0 (stem vol)

• 50.5 3.53 0 (head vol)

• 50.0 1.34** 33 0 8 227

• 45.0 13.10 148 0 8 277

• 40.0 11.83 134 0 8 277

• 35.0 9.57* 108 0 116 268

• 30.0 10.67* 121 0 95 276

• 25.0 11.30 128 0 103 277

• 20.0 11.09 125 0 94 284

• 15.8 <‐‐ return depth

• 15.0 9.96* 113 0 23 291

• 10.0 10.21* 116 0 112 288

• 5.0 12.32 139 0 115 286

• 0.0 5.44** 62 0 36 284

• 0.00 0 (spill vol)

• [stop 12:15 (00:21:33)]

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Plotted with 5 ft. increments Volume always > 100%

Magnetic Flow Meter

Plotted with 2 ft. increments Volume drops below 100% at Several locations

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Field Printout Grouting Data with 2 foot increment


• pumped volume AVG line

• depth dT volume ratio Pressure

• (ft) (sec) (ft3) (%) (PSI)


• 50.5 5.40 (Stem+Head)

• 52.0 1 0.00** 0 0

• 50.0 2 1.34** 38 0

• 48.0 7 4.80 135 0

• 46.0 7 6.32 177 0

• 44.0 5 4.03* 113 0

• 42.0 6 4.87 137 0

• 40.0 7 4.80 135 0

• 38.0 5 5.01 141 0

• 36.0 5 3.53** 99 0

• 34.0 5 3.28** 92 0

• 32.0 6 3.81* 107 0

• 30.0 8 4.59 129 0

• 28.0 5 5.76 161 0

• 26.0 5 2.93** 82 0

• 24.0 6 4.24* 119 0

• 22.0 7 3.96* 111 0

• 20.0 1120 5.76 161 0

• 18.0 9 6.07 170 0

• 16.0 4 2.54** 71 0

• 15.8 <‐‐ return depth (‐5.2)

• 14.0 5 3.46** 97 0

• 12.0 7 3.00** 84 0

• 10.0 8 5.26 148 0

• 8.0 7 2.72** 76 0

• 6.0 11 7.77 218 0

• 4.0 4 3.43** 96 0

• 2.0 4 3.88 109 0

• 0.0 1 0.00** 0 0

• 0.00 (spill vol)

• [stop 12:15 (00:65528:65522)]

11.0: Embedded Jack, Rapid and Dynamic Load Testing

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Multi‐Level Embedded Jack Load Testing

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)

Reference: ASCE 2006 Conference, Hayes and Meyer

Comparison of Embedded Jack Load Tests and Conventional Top Load Tests


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Bi‐Directional Load Testing

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

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


Multi‐Level Embedded Jack Load Testing


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Initial ACIP Pile Applications

Initial applications

– 24‐inch‐diameter, 100‐ft long piles• 13‐inch diameter O‐cell

• 2,600 kips (Equivalent Top Load)

– 30‐inch‐diameter, 120‐ft long piles• 16‐inch diameter O‐cell

• 4,240 kips (Equivalent Top Load)


Configuration and Simulation Piles


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Embedded Jack Assembly


Results of Bi‐Directional Load Testing


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Results of Bi‐Directional Load Testing


Rapid and Dynamic Load Testing Techniques

• Hammer Systems (DLT‐High Strain Dynamic Testing)

– Apple System

• Statnamic Load Test (RLT)

• Fundex System (RLT)

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Rapid and Dynamic Load Testing Techniques

RLT‐Statnamic by AFTFundex System

Apple Systems by GRL

Typical Instrumentation

• Load cells to measure force

• Accelerometers and strain sensors

• Deflection recorded utilizing optical receivers, transmitters and/or other remote techniques

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Apple Dynamic Load Testing System

Graphics and photos courtesy ofPile Dynamics Inc

Pile VelocityPile Velocity

ForceForce

TraditionalTraditionalF = maF = ma

Top transducer

Top transducer

F

V

Strain / ForceStrain / Force

AccelerometerAccelerometer

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Dynamic Testing of ACIP piles

• need large drop weight • Apply single blows of varying drop height•To move pile to a permanent set

• prepare pile top• excavate or build up pile top• flat top protected by cushion

– attach sensors

• analysis method•Signal Matching (e.g. CAPWAP®)

Attach sensors to a flat spot on shaft

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Statnamic Load Testing Concept‐RLT

Reference: O’Neill and Reese, 1999

Statnamic Load Test‐RLT

Statnamic Schematic

Gravel container

GravelReaction massesSilencerCylinder

Laser

Laser beam

Pile to be tested

Piston

Laser sensorPlatform

Load cell

GravelContainer

Masses

Pile

Laser

Gravel

Graphics courtesy of Applied Foundation Testing Inc

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Fundex Load Testing System‐RLT

12.1: Low Strain Pile Integrity Testing

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Low Strain Pile Integrity Testing• Impact pile top with a small handheld hammer

– Creates a compressive wave within the pile

• Accelerometer at pile top measures pile top movement due to the impact and any reflection waves

– Reflections come from pile toe or from any changes in pile cross section

• Received acceleration signal is digitally integrated to get velocity

• Intended to find MAJOR defects within the pile

• Standard Test Method for Low Strain Impact Integrity Testing of Deep Foundations (ASTM D5882)

Low Strain Pile Integrity Testing

Advantages• Fast and economical

– One individual can test many piles in one day

• Can test any/all piles on site with no special installation procedures required

• No special pile installation method needed

– No need to install access tube, no special pile buildup, etc.

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Low Strain Pile Integrity Testing

Disadvantages

• Limited L/D ratio

– Tougher to get toe reflection when L > 30 Dia.

• Non‐uniform piles create many reflections making data interpretation difficult

Good Pile

Bad Pile

Low Strain Pile Integrity Test

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Pile Integrity Test Good Pile

-0.15

0.00

0.15

0.3040 FT GOOD - 5: # 1cm/s

Vel

F/Z

MA: 1.00MD: 2.44LE: 12.19WS: 3962LO: 0.61HI: 30.5PV: 0T1: 32

0 2 4 6 8 10 12 m

T1 Toe

Pile Integrity Test Defective Pile

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

Wide “input” implies defect near top

“We excavated and found some caves. I could stick my hand all the way to the middle of the pile and pull out hand‐fulls of soil.”

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PTA‐59

TP3

Bad pile excavated to reveal neck

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PIT and PIR Data Correlation

PIT and PIR‐A agree on defect location.

Rise to rise evaluation: defect at ~ 28 ft.

Low grout (44%) from 28 to 26 ft.

PIT vs. PIR Correlation• Withdrawal Data [start 14:06]• pumped volume line_pres• depth volume ratio min max• (ft) (ft3) (%) (PSI)• 28.0 2.30** 94 200 252• 26.0 5.01 204 198 268• 24.0 1.87** 76 198 268• 22.0 2.01** 82 194 252• 20.0 6.18 252 194 263• 18.7 <‐‐ return depth• 18.0 1.66** 68 198 252• 16.0 6.07 247 198 283• 14.0 3.28 134 198 283• 12.0 3.64 148 201 261• 10.0 4.45 181 201 261• 8.0 3.85 157 205 260• 6.0 3.53 144 205 260• 4.0 2.68* 109 203 260• 2.0 3.39 138 203 260• 0.0 3.85 157 69 269• 0.04 (spill vol)• [stop 14:11 (00:04:21)]

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12.2: Single Hole Sonic Logging

Single Hole Sonic Logging

• Tube is installed with the rebar cage

– Tube MUST be plastic for SSL test

• Ultrasonic pulse is transmitted from the transmitter probe

• Receiver probe receives signals from transmitter

• Received signal paths include direct path from transmitter and reflections from impedance changes

The Deep Foundations Institute’s Cast‐in‐Place Piling Seminar‐ KC '09

43

Single Hole Sonic Logging

Good

Defect

How to find defects?

1. Reduced signal strength (lower “energy”)2. Delayed arrival time

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SSL for Uniform Pile and Defective Pile

• ``

R

T T

R

Uniform pile with consistent arrival times

Pile with Defect will have delayed arrival time and reduced energy at defect location

•SSL comparison with PIT for a defective pile

Defect clearly shown in PIT and SSL data

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12.3: Thermal Integrity Testing

Thermal Integrity Profiling• Patented Research developed at the University of South Florida

• Two measurement techniques

• IR probes scan the pile via CSL access tubes

• Thermal Wires are cast into the pile attached to cage or center bar

• Measures the elevated temperatures during the hydration process to determine pile integrity

46

Thermal Integrity Profiling

• Test can reveal anomalies both inside and outside the reinforcing cage

• Test can reveal cage alignment problems– Minimum cover can be verified

• Test is completed within first few days after installation (depending upon pile diameter)– Accelerates construction

• Limited use on ACIP piles to date

Thermal Integrity Profiling

• TIP test shows bulge in upper section of shaft (NW portion)

• Excavation verifies TIP analysis

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SUMMARY

• Quality control is being successfully implemented

• The DFI has been and continues to be a leader in developing quality control guides for ACIP piles

• Quality control is necessary throughout the entire ACIP pile construction process

• Automated monitoring is being utilized to help with quality control. AME is used as a supplement to, but can not replace, qualified Q/C Contractors and Inspectors

• NDT methods are being widely utilized to find major defects within a pile– Understand the limitations of the selected NDT method

• Should questionable conditions be observed during the pile installation process, the most cost effective and time saving solution is often to re‐drill and re‐grout the pile

Documents

Grouting Piscsalko PPT