Investigation and guidelines for drilled shaft inspections

GEORGIA DOT RESEARCH PROJECT 19-07 FINAL REPORT
INVESTIGATION AND GUIDELINES FOR DRILLED SHAFT EXCAVATION INSPECTIONS
OFFICE OF PERFORMANCE-BASED MANAGEMENT AND RESEARCH
600 WEST PEACHTREE STREET NW ATLANTA, GA 30308

TECHNICAL REPORT DOCUMENTATION PAGE

1. Report No.:

2. Government Accession No.:

GDOT-GA-21-1907

N/A

4. Title and Subtitle:

Investigation and Guidelines for Drilled Shaft Excavation

Inspections

3. Recipient's Catalog No.: N/A
5. Report Date: May 2021
6. Performing Organization Code: N/A

7. Author(s): Adam Kaplan, Ph.D. (PI)
Jayhyun Kwon, Ph. D., P.E (co-PI) (https://orcid.org/0000-0001-
7084-7942);
9. Performing Organization Name and Address: Kennesaw State University Civil and Environmental Engineering 655 Arntson Drive, Marietta, GA 30060 Phone: (470) 578-5080 E-mail: jkwon9@kennesaw.edu
12. Sponsoring Agency Name and Address: Georgia Department of Transportation Office of Performance-based Management and Research 600 West Peachtree St. NW Atlanta, GA 30308

8. Performing Organization Report No.: 19-07
10. Work Unit No.: N/A
11. Contract or Grant No.: KSURV-431550 GDOT PI#16890
13. Type of Report and Period Covered: Final; October 2019-May 2021
14. Sponsoring Agency Code: N/A

15. Supplementary Notes: Conducted in cooperation with the U.S. Department of Transportation, Federal Highway Administration.
16. Abstract: A proper drilled shaft (a.k.a. caisson) excavation inspection is crucial to the structural integrity of the shaft. Factors such as irregularities on the sidewalls, verticality of the shaft, and debris on the shaft bottom play an important role in the constructability and the structural performance of the shaft under service loads. In the case of a dry shaft construction, the field inspector may visually assess the walls and base of the drilled shaft by entering the excavation. An entry into a drilled shaft requires compliance with Occupational Safety & Health Agency (OSHA) requirements, which may include testing for toxic and flammable gases. Due to such safety concerns, field inspectors have been reluctant to carry out such inspections. In this study, a range of drilled shaft excavation inspection equipment with the capability to eliminate sending a human into the dry shaft excavation has been investigated. Equipment varies in size, cost and technology. The field effectiveness of several equipment types was evaluated during field demonstration events. Important aspects of all equipment and field observations have been summarized in tables to serve as a guideline for equipment selection decisions. Finally, equipment selection recommendations have been made based on six criteria: safety, cost, mobility, accuracy, speed, and state DOT experience.

17. Keywords: Drilled shaft, base cleanliness, verticality, inspection equipment, dry shafts, sonar, caliper

18. Distribution Statement: No restrictions. This document is available through the National Technical Information Service, Springfield, VA 22161.

19. Security Classification 20. Security Classification (of this

(of this report):

page):

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Unclassified

21. No. of Pages: 22. Price:

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Reproduction of completed page authorized

GDOT Research Project 19-07 Final Report
INVESTIGATION AND GUIDELINES FOR DRILLED SHAFT INSPECTIONS By
Adam Kaplan, Ph.D. Associate Professor Department of Civil and Environmental Engineering
Jayhyun Kwon, Ph.D., P.E. Assistant Professor Department of Civil and Environmental Engineering
Kennesaw State University Research and Service Foundation
Contract with Georgia Department of Transportation
In cooperation with U.S. Department of Transportation Federal Highway Administration
May 2021
The contents of this report reflect the views of the authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views of the Georgia Department of Transportation or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation.
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Symbol
in ft yd mi
in2 ft2 yd2 ac mi2
fl oz gal ft3 yd3
oz lb T
oF
fc fl
lbf lbf/in2
Symbol
mm m m km
mm2 m2 m2 ha km2
mL L m3 m3
g kg Mg (or "t")
oC
lx cd/m2
N kPa

SI* (MODERN METRIC) CONVERSION FACTORS

APPROXIMATE CONVERSIONS TO SI UNITS

When You Know

Multiply By

To Find

LENGTH

inches

25.4

millimeters

feet

0.305

meters

yards

0.914

meters

miles

1.61

kilometers

AREA

square inches

645.2

square millimeters

square feet

0.093

square meters

square yard

0.836

square meters

acres

0.405

hectares

square miles

2.59

square kilometers

VOLUME

fluid ounces

29.57

milliliters

gallons

3.785

liters

cubic feet

0.028

cubic meters

cubic yards

0.765

cubic meters

NOTE: volumes greater than 1000 L shall be shown in m3

MASS

ounces

28.35

grams

pounds

0.454

kilograms

short tons (2000 lb)

0.907

megagrams (or "metric ton")

TEMPERATURE (exact degrees)

Fahrenheit

5 (F-32)/9

Celsius

or (F-32)/1.8

ILLUMINATION

foot-candles foot-Lamberts

10.76 3.426

lux candela/m2

FORCE and PRESSURE or STRESS

poundforce

4.45

newtons

poundforce per square inch

6.89

kilopascals

APPROXIMATE CONVERSIONS FROM SI UNITS

When You Know

Multiply By

To Find

LENGTH

millimeters

0.039

inches

meters

3.28

feet

meters

1.09

yards

kilometers

0.621

miles

AREA

square millimeters

0.0016

square inches

square meters

10.764

square feet

square meters

1.195

square yards

hectares

2.47

acres

square kilometers

0.386

square miles

VOLUME

milliliters

0.034

fluid ounces

liters

0.264

gallons

cubic meters

35.314

cubic feet

cubic meters

1.307

cubic yards

MASS

grams

0.035

ounces

kilograms

2.202

pounds

megagrams (or "metric ton")

1.103

short tons (2000 lb)

TEMPERATURE (exact degrees)

Celsius

1.8C+32

Fahrenheit

ILLUMINATION

lux candela/m2

0.0929 0.2919

foot-candles foot-Lamberts

FORCE and PRESSURE or STRESS

newtons

0.225

poundforce

kilopascals

0.145

poundforce per square inch

Symbol
mm m m km
mm2 m2 m2 ha km2
mL L m3 m3
g kg Mg (or "t")
oC
lx cd/m2
N kPa
Symbol
in ft yd mi
in2 ft2 yd2 ac mi2
fl oz gal ft3 yd3
oz lb T
oF
fc fl
lbf lbf/in2

iii

TABLE OF CONTENTS
EXECUTIVE SUMMARY ...............................................................................................1 CHAPTER 1: INTRODUCTION.....................................................................................4
ORGANIZATION OF THE DOCUMENT ............................................................... 4 DRILLED SHAFT TYPES .......................................................................................... 5 VERTICALITY ............................................................................................................ 6 BASE CLEANLINESS ................................................................................................. 7 CHAPTER 2: LITERATURE REVIEW ........................................................................9 DRILLED SHAFT EXCAVATION INSPECTIONS ............................................... 9
Verticality ................................................................................................................ 10 Base Cleanliness ...................................................................................................... 15 State DOT Tolerances............................................................................................. 20 INSPECTION EQUIPMENT FOR VERTICALITY ASSESSMENT.................. 24 Mechanical Caliper Logging System..................................................................... 24 Shaft Area Profile Evaluator (SHAPE) ................................................................ 28 Borehole Inclination Tester (BIT) ......................................................................... 31 SoniCaliper .............................................................................................................. 34 INSPECTION EQUIPMENT FOR BASE CLEANLINESS.................................. 37 Shaft Quantitative Inspection Device (SQUID) ................................................... 37 Ding Inspection Device (DID) ................................................................................ 41 Shaft Inspection Device (Mini-SID) ...................................................................... 44 CHAPTER 3: FIELD DEMONSTRATION EVENTS ................................................47 FIELD DEMONSTRATION #1: MECHANICAL CALIPER, SID, SHAPE, SQUID .......................................................................................................................... 47 Mechanical Caliper ................................................................................................. 50 Shaft Inspection Device (SID) ................................................................................ 53 Shaft Area Profile Evaluator (SHAPE) ................................................................ 56 Shaft Quantitative Inspection Device (SQUID) ................................................... 58 FIELD DEMONSTRATION #2: DID ...................................................................... 61 CHAPTER 4: CONCLUSIONS .....................................................................................65 CHAPTER 5. RECOMMENDATIONS ........................................................................67 APPENDIX A: TECHNICAL SPECS ...........................................................................70 SHAFT AREA PROFILE EVALUATOR (SHAPE)............................................... 71 SHAFT QUANTITATIVE INSPECTION DEVICE (SQUID) .............................. 72 DING INSPECTION DEVICE.................................................................................. 74 MECHANICAL CALIPER ....................................................................................... 75
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SHAFT INSPECTION DEVICE (MINI-SID) ......................................................... 76 SONICALIPER........................................................................................................... 78 BOREHOLE INCLINATION TESTER (BIT)........................................................ 79 APPENDIX B: SAMPLE INSPECTION REPORTS ..................................................80 SHAFT AREA PROFILE EVALUATOR (SHAPE)............................................... 81 SHAFT QUANTITATIVE INSPECTION DEVICE (SQUID) .............................. 95 MECHANICAL CALIPER ..................................................................................... 108 SHAFT INSPECTION DEVICE (MINI-SID) ....................................................... 117 DING INSPECTION DEVICE................................................................................ 118 SONICALIPER......................................................................................................... 121 APPENDIX C: SAMPLE CONTRACT SPECIFICATIONS ...................................130 DRILLED SHAFT BASE CLEANLINESS USING SQUID ................................ 131 DRILLED SHAFT VERTICALITY AND PROFILE USING SONICALIPER 136 ACKNOWLEDGEMENTS ..........................................................................................138 REFERENCES ...............................................................................................................139
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LIST OF FIGURES
Figure 1. Illustration. Definition of a dry shaft(2)................................................................ 6 Figure 2. Illustration. Definition of verticality.................................................................... 7 Figure 3. Illustration. Typical sediment profile. ................................................................. 7 Figure 4. Illustration. Vertical alignment check with a four feet level. ............................ 11 Figure 5. Illustration. Verticality check with plumb bob method..................................... 13 Figure 6. Illustration. Example of verticality check with plumb bob method. ................. 14 Figure 7. Photo. Weighted tape......................................................................................... 16 Figure 8. Photo. Weighted tape used in base soundings................................................... 16 Figure 9. Illustration. Weighted tape sounding locations. ................................................ 16 Figure 10. Chart. Sample base cleanliness inspection form. ............................................ 17 Figure 11. Photos. The Downhole Camera (DHC) System .............................................. 19 Figure 12. Photo. Parts of mechanical caliper. ................................................................. 24 Figure 13. Photo. Calibration of the caliper for verticality measurement. ....................... 25 Figure 14. Photo. Shape assessment with arms extended during upward motion. ........... 26 Figure 15. Photo. SHAPE and its display unit before lowered into the shaft................... 28 Figure 16. Illustration. Components of Borehole Inclination Tester (BIT). ..................... 31 Figure 17. Photo. Inclinometer attached to a bucket. ....................................................... 32 Figure 18. Illustration. Sonar data points and calculation of shaft area............................ 34 Figure 19. Photo. SoniCaliper lowered into the shaft. ...................................................... 35 Figure 20. Illustration. SQUID with retractable plates. .................................................... 37 Figure 21. Illustration. Determination of sediment thickness using Terzaghi's bearing capacity formula................................................................................................................ 39 Figure 22. Photos. Ding Inspection Device measuring sediment thickness. .................... 41 Figure 23. Photo. Mini-SID diving bell lowered into the shaft via winching system. ..... 44 Figure 24. Illustration. Mini-SID diving bell and sediment thickness gages.................... 45 Figure 25. Illustration. The location of the second field demonstration event. ................ 48 Figure 26. Photo. Bent 3, Shaft 1...................................................................................... 48 Figure 27. Chart. Boring log at SR53 Bent 3.................................................................... 49 Figure 28. Photo. Mechanical Caliper Logging system during field operation................ 50 Figure 29. Graph. Deviation profile and the criteria......................................................... 51 Figure 30. Graph. Diameter profile................................................................................... 52 Figure 31. Graph. Shape profile........................................................................................ 52 Figure 32. Photo. Mini-SID during field operation. ......................................................... 53 Figure 33. Photos. Sediment thickness measurement. ...................................................... 54 Figure 34. Photo. SHAPE and its display unit.................................................................. 56 Figure 35. Photo. Preparing SQUID for base cleanliness assessment. ............................. 58 Figure 36. Illustration. Data collection at the shaft base using SQUID............................ 59 Figure 37. Illustration. Location of the third field demonstration event........................... 61 Figure 38. Photo. DING inspection device operated by one person................................. 62 Figure 39. Photo. Digital readout for the DING inspection device. ................................. 62 Figure 40. Photo. Extension rod for DING inspection device. ......................................... 63
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LIST OF TABLES Table 1. Mini-SID and DID base sediment thickness measurements............................... 19 Table 2. State DOT practice for shaft verticality and base cleanliness tolerances. .......... 21 Table 3. GDOT vs State DOTs, drilled shaft excavation tolerances. ............................... 23 Table 4. Highlights of Mechanical Caliper Logging system. ........................................... 27 Table 5. Highlights of SHAPE.......................................................................................... 30 Table 6. Highlights of BIT................................................................................................ 33 Table 7. Highlights of SoniCaliper ................................................................................... 36 Table 8. Highlights of SQUID .......................................................................................... 40 Table 9. Highlights of DID ............................................................................................... 43 Table 10. Highlights of Mini-SID..................................................................................... 46 Table 11. Field effectiveness summary for Mechanical Caliper: Pros and Cons ............. 52 Table 12. Field effectiveness summary for Mini-SID: Pros and Cons ............................. 55 Table 13. Field effectiveness summary for SHAPE: Pros and Cons................................ 57 Table 14. Summary of sediment thickness using SQUID. ............................................... 59 Table 15. Field effectiveness summary for SQUID: Pros and Cons ................................ 60 Table 16. Sediment thickness data using DID. ................................................................. 63 Table 17. Field effectiveness summary for DID: Pros and Cons. .................................... 64 Table 18. Equipment suitable for dry shaft base cleanliness assessment. ........................ 66 Table 19. Equipment suitable for dry shaft verticality assessment................................... 66 Table 20. Final recommendations in the order of preference for verticality and base cleanliness equipment for dry shafts................................................................................. 69
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AASHTO ADSC ASTM BIT DHC DID FDOT FHWA GDOT LVDT NCDOT NHI NYDOT OSHA PZT QA SCDOT SHAPE SID SQUID

LIST OF ABBREVIATIONS
American Association of State Highway and Transportation Officials The International Association of Foundation Drilling American Society for Testing and Materials Borehole Inclination Tester Downhole Camera DING Inspection Device Florida Department of Transportation Federal Highway Administration Georgia Department of Transportation Linear Variable Differential Transformer North Carolina Department of Transportation National Highway Institute New York Department of Transportation Occupational Safety & Health Agency Pan-Zoom-Tilt Quality Assurance South Carolina Department of Transportation Shaft Area Profile Evaluator Shaft Inspection Device Shaft Quantitative Inspection Device

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EXECUTIVE SUMMARY Drilled shaft (a.k.a. caisson) foundations are desired due to their high resistance to axial and lateral loads. Such foundation systems show increasing resistance with increasing foundation displacements under service loads. Proper engineering design and quality control practices during the construction of drilled shafts lead to a foundation system that shows more resistance at small displacements without risking the integrity of the superstructure. Factors such as irregularity and verticality of the sidewalls and debris thickness at the bottom of a drilled shaft play an important role in controlling the foundation displacements and the structural performance. Therefore, inspection of shaft excavations prior to concrete placement is an important step in the quality control of such deep foundations. Shaft excavation methods depend on the subsurface conditions. In stiff to hard clay soils or cemented sands, open dry excavation with minimal casing above the water table is a common method. In soft soil conditions, the casing can be extended deeper into the shaft to prevent collapse of the side walls. In a wet construction technique, the shaft is filled with slurry to support the sidewalls and the drilling activity continues in a wet environment. In the case of a dry excavation, although it is not recommended, the field inspector may visually assess the walls and bottom of the drilled shaft by entering the excavation though inspectors are not expected to perform activities in unsafe conditions. An entry into a drilled shaft requires compliance with Occupational Safety & Health Agency (OSHA) requirements which may include testing for toxic and flammable gases. Due to such safety concerns, field inspectors have been reluctant to carry out such inspections. The Georgia Department of Transportation (GDOT) Geotechnical Bureau conducted drilled shaft
1

foundation excavation inspections by sending inspectors into the shaft as per Special Provision 524 until August 2018. The Bureau has since started the search for available devices and techniques to perform dry shaft excavation inspections without sending a person into the shaft excavation. The literature survey revealed a limited number of devices and methods available to help field inspectors perform effective assessment of dry shafts. As no ASTM testing procedure is currently available for the base cleanliness assessment and sediment thickness, traditional weighted tape and more quantitative testing tools are implemented. The common acceptance criteria for sediment thickness is 50 percent of base shall have < inch of sediment and no area of the shaft base shall be more than 1 inches. The traditional inspection method is not quantitative and instead is based on the results of a sounding tool, such as a #18 bar attached to a tape. Beginning in the late 80's, advanced quantitative calipers have been developed to measure sediment thickness. Early calipers use graduated gages inside a dewatered and pressurized bell. Sediment thickness readings were taken by a camera located inside the bell. Newer tools are more quantitative and use LVDTs to measure sediment thickness directly or use probes advanced into the sediment to measure penetration resistance. Assessment of open shaft verticality requires a different set of equipment than the base cleanliness measuring devices. Currently, no device is available that can measure both base cleanliness and verticality. In this research study, an attempt was made to develop such a device. However, it is still in the development stage. The available verticality testing tools use either mechanical arms touching the walls of the shaft or ultrasonic transmitters and receivers that work in wet or dry environments. The common acceptance criteria for
2

verticality is a maximum center deviation of 1 percent to 2 percent of the shaft length. The new standard for testing verticality, ASTM D8232-18(1), was published in 2018. It provides two testing procedures, one with inclinometers and one with diameter measuring tools (laser, ultrasonic or mechanical). However, no recommendations are provided for precision and bias. The authors indicate that they are still seeking data from users to make a recommendation on precision. The inspection devices vary in size and level of required technology to operate. Selection of a device or method requires a careful review of cost, capacity, limitations, availability, accuracy, and field effectiveness. In this research effort, a range of devices and techniques have been evaluated through a comprehensive literature survey and three field demonstrations in the Atlanta area to provide the GDOT Geotechnical Bureau a resource to facilitate engineering decisions in conducting dry shaft excavations without sending a person into the excavation.
3

CHAPTER 1: INTRODUCTION
ORGANIZATION OF THE DOCUMENT This report is intended as a resource for the GDOT concerning available drilled shaft verticality and base cleanliness inspection tools and techniques for dry environments. First, a survey of current inspection specifications and tolerances of several department of transportation offices (DOTs) in the United States has been conducted. The latest FHWA publications on drilled shafts were also surveyed for recent developments and recommendations in the area of dry shaft inspections. Next, a comprehensive search has been conducted and several companies and their inspection devices have been identified for further evaluation. Several of these companies were invited to perform field demonstrations to evaluate the field effectiveness of their equipment. The technical specifications of devices and sample inspection reports have been gathered and included in this report. Additionally, sample contract specifications have been obtained from technology vendors for GDOT's reference and are included in this report. Chapter 2 summarizes the literature review of inspection devices as well as drilled shaft excavation inspection specifications of GDOT and other state DOTs. For each quantitative inspection device, a table was created to summarize the highlights and provide links for reference material. No summary table was created for the subjective and non-quantitative techniques such as weighted tape, plumb bob and borehole cameras. The highlights table includes pricing information for purchase and rentals where available. These are approximate numbers provided by the vendors and should not be considered as final quotes.
4

Chapter 3 explains all field demonstration events and discusses field effectiveness of the inspection equipment. A pros and cons table has been included for each device as a quick reference. Inspection test results from multiple devices are compared where available. A different drilled shaft was used in each field demonstration event. Therefore, it was not possible to compare the outcome of every device. Chapter 4 presents conclusions and recommendations derived from the literature survey and field demonstrations. Technical equipment specifications are collected and presented in Appendix A. Sample inspection reports are presented in Appendix B. Finally, two contract specifications are included in Appendix C as a reference.
DRILLED SHAFT TYPES The diameter of drilled shafts can be from 3 ft to 12 ft, and the length can be up to 300 ft. Drilled shafts are installed by dry, wet or steel cased methods. The dry construction method is also called the open hole method. In some cases, dry conditions can be achieved by temporary casing to prevent water from entering the excavation. In other cases, steel casing may be used in a dry excavation if there is a risk of caving soil. FHWA GEC-10(2) provides a practical definition of a dry shaft. A shaft excavation is considered dry when the standing water depth at the base is less than 3 inches and water entering the excavation is less than 12 inches per hour as illustrated in figure 1. The focus of this research study is dry shafts and the inspection techniques that apply to dry shaft excavations.
5

Figure 1. Illustration. Definition of a dry shaft(2).
In the wet shaft construction method, the hole is filled with water, bentonite or polymer slurry. The impact of different wet shaft construction methods on base cleanliness and verticality is beyond the scope of this research study.
VERTICALITY Inspection of a dry shaft excavation includes quantifying the verticality of the shaft walls and determining the shape profile. Verticality of a shaft is defined as the maximum center deviation divided by the length of the shaft as illustrated in figure 2. The same definition is used in verticality measurements of the field demonstrations conducted during this research study. Common verticality tolerance used by many state DOTs is 1.5 percent to 2 percent where in most cases 1.5 percent is used for friction shafts and 2.0 percent is used for end-bearing shafts.
6

Figure 2. Illustration. Definition of verticality.
Figure 3. Illustration. Typical sediment profile. BASE CLEANLINESS The thickness of the debris at the base must be monitored and cleaned out as necessary. Soft debris remaining at the base may create excessive foundation settlement. The sediment consists of light weight material with a unit weight less than 100 pcf and debris with a unit weight range of 100 pcf to 120 pcf(3) as illustrated in figure 3. Most inspection methods measure the overall thickness including debris and light weight material. Only one
7

inspection device, SQUID, detects the lightweight material by measuring the penetration resistance and ignores it when reporting the sediment thickness. The lightweight material is assumed to be replaced by fresh concrete during placement. For end-bearing shafts, common sediment thickness tolerance used by many state DOTs is 50 percent of base shall have < inch of sediment and no area of shaft base shall be more than 1 inches. Some states allow up to six inches of loose material for friction piles(4).
8

CHAPTER 2: LITERATURE REVIEW
DRILLED SHAFT EXCAVATION INSPECTIONS Quality assurance in a drilled shaft construction project requires inspection at every stage of the construction; before, during and after. Chapter 15 of the FHWA GEC-10 Drilled Shafts Manual(2) outlines inspection methods for every stage of the shaft construction process, provides sample inspection forms and a comprehensive checklist for inspectors. In this publication, the FHWA recommends several modern techniques for verticality and base cleanliness, such as the Mechanical Caliper Logging System, Shaft Inspection Device (Mini-SID), and SoniCaliper. The National Highway Institute (NHI) offers "FHWA-NHI132070 Drilled Shaft Foundation Inspection," a 2.5-day course that covers a wide arrange of topics including contract documents and specifications for compliance. Several state DOTs and universities offer reference manuals, training courses or certification programs for drilled shaft construction inspectors. For example, FDOT has an online inspector training course(5), NYDOT provides Drilled Shaft Inspector's Guidelines(6), Kansas State University offers a certification course(7), and the Oregon DOT has a Drilled Shaft Foundation Inspection Certification program(8). Additionally, another comprehensive inspector's manual is available from the International Association of Foundation Drilling (ADSC)(4). Among all inspection procedures, the excavation inspection plays a critical role since it has a preventive nature by detecting defects before the placement of concrete. A proper shaft excavation inspection may prevent potential construction delays and financial damage due to poor shaft performance and structural defects.
9

The impact of base cleanliness on the end bearing capacity of shafts has been studied by researchers. Camp, Brown and Mayne(16) conducted field tests on 12 shafts constructed with different methods. The base cleanliness, measured by Mini-SID, varied between 10 mm (0.4 inch) and 40mm (1.57 inches), and no correlation was found between the end bearing resistance and base cleanliness. Currently, many state DOTs use an upper threshold of 1.5 inches for base cleanliness. Brown (13) investigated the effect of construction on axial capacity of drilled shafts in Piedmont soils. In this research, end bearing capacity of shafts constructed by bentonite slurry was found to be significantly lower than other shafts. It was suggested that base cleanliness could be the reason, but no correlations were presented since a sounding inspection technique was used for base cleanliness assessment.
Verticality Verticality of drilled shafts must be maintained within allowable limits during construction. Shafts that are not aligned properly may be subject to poor performance due to additional bending moment and stress concentrations. FHWA GEC -10(2) recommends periodically checking verticality of the excavation by holding a 4-ft level on the Kelly bar during the construction process as illustrated in figure 4. Additional examples are provided of more advanced techniques, such as mechanical caliper and ultrasonic methods. A 4-ft level can detect misalignment of the shaft near the surface but not at deeper locations inside the excavation. Traditionally, the plumb bob technique is used to check the verticality of the entire shaft once the excavation is completed. When the maximum tolerance, the shaft length times maximum acceptable verticality, is known then a plumb
10

bob is lowered into the hole to determine if the shaft's center deviation at the base is within the allowable limits. This process is illustrated along with an example in figure 5 and figure 6.
Source: FDOT Figure 4. Illustration. Vertical alignment check with a four feet level. FHWA GEC -10(2) provides examples of devices for more quantitative techniques such as the Mechanical Caliper or SoniCaliper to conduct shape and verticality assessment of drilled shafts. These methods are more quantitative than the plumb bob method and provide detailed information regarding the shape of the excavation. Although not mentioned in FHWA GEC -10(2), the Shaft Area Profile Evaluator (SHAPE) developed by Pile Dynamics, Inc., uses ultrasonic methods similar to SoniCaliper, and measures verticality and shape of the shaft. During the second field demonstration event of this study, the Mechanical Caliper and SHAPE were used to measure the verticality of a 112 ft wet shaft. Both devices yielded a similar verticality of 0.5 percent.
11

Another quantitative device is the Borehole Inclination Tester (BIT) that can measure only the verticality. The inclination sensor is attached to the drilling bucket and no shape data is collected. BIT conforms to the recently published ASTM standard D8232-18 for measuring shaft inclination.
12

Source: NYDOT Figure 5. Illustration. Verticality check with plumb bob method.
13

Source: NYDOT Figure 6. Illustration. Example of verticality check with plumb bob method.
14

Base Cleanliness In order to achieve an effective end bearing capacity for drilled shafts, the base must be free of debris or any soft material. The drilling contractor should complete a proper cleanout using cleanout buckets, pumps or air lifts before placing the concrete. The thickness of the debris at the base is measured with subjective or quantitative techniques. FHWA GEC -10(2) recommends three methods for measuring base cleanliness:
1- Weighted tape. 2- Sounding with neutral buoyancy rod. 3- Shaft Inspection Device (Mini-SID) In the weighted tape method, soundings are made at five sides of the base. A sound "thump" is considered as an indication of rock base. A #18 rebar is recommended to be attached to the tape as shown in figure 7. Figure 8 and figure 9 illustrate how the tape is lowered into the shaft and the locations where the sounding is performed. The NCDOT provides a weighted tape method instructional video(9). Although used by many inspectors, the weighted tape method is not quantitative and is highly subjective. The literature survey suggests that the neutral buoyancy rod is not a common method. No additional sources yielded how the soundings are conducted with this technique. The Shaft Inspection Device (Mini-SID) was originally developed in 1982 for the Florida Department of Transportation and was used during the construction of the Sunshine Skyway Bridge. A more cost-effective version, Mini-SID, was developed in 1994. Though more quantitative than the weighted tape method, the sediment thickness readings are taken visually from a camera located inside the device, thus rendering partially subjective results. The Mini-SID has been widely used by many state DOTs including FDOT, SCDOT and
15

NCDOT(4). A sample base cleanliness inspection form recommended by FHWA GEC 10(2) is shown in figure 10. This form uses the term "visual" to refer to the Mini-SID method. More information on Mini-SID is presented later in this chapter.

Source: NCDOT
Figure 7. Photo. Weighted tape.

Source: ODOT
Figure 8. Photo. Weighted tape used in base soundings.

Source: ODOT Figure 9. Illustration. Weighted tape sounding locations.
16

Source: FHWA Figure 10. Chart. Sample base cleanliness inspection form.
17

Another device used to measure sediment thickness is the Shaft Quantitative Inspection Device (SQUID). The SQUID has three retractable probes and can measure penetration resistance as the probes are advanced into the sediment. Moghaddam, Hannigan, and Anderson(3) conducted a series of base sediment thickness assessments in wet shafts using both Mini-SID and SQUID and compared their measurements. The relationship between the two methods was studied and a predictive model with R2=0.57 was determined, suggesting a potential statistical relation exists between Mini-SID and SQUID measurements. A recently developed DING Inspection Device (DID)(10) is increasingly being used by several institutions and contractors. Currently, the device has been used or recommended by the following agencies/organizations:
Florida Department of Transportation California Department of Transportation Virginia Department of Transportation City of San Francisco District Department of Transportation Oklahoma Department of Transportation Deep Foundation Institute European Federation of Foundation Contractors Ding, McIntosh, and Simon(11) conducted base cleanliness measurements using Mini-SID and DID on three shafts constructed by the wet method. DID results yielded slightly higher sediment thickness measurements than Mini-SID as shown table 1.
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Table 1. Mini-SID and DID base sediment thickness measurements.

Shaft
Shaft 1 Shaft 2 Shaft 3

Mini-SID

Min. (mm) Max. (mm)

12

25

0

12

12

38

DID

Min. (mm) Max. (mm)

19.1

25.4

5.1

30.1

33.0

99.1

Although not quantitative inspection equipment, the Downhole Camera (DHC) (see figure 11) was developed to visually observe the condition of sidewalls. The device is compact, easy to use and has the capability to video record the sidewalls and base of the shaft. In case of caving soil conditions, sidewall irregularities may have a negative impact on the shear resistance of the shaft. Concrete filling the voids on the sidewalls creates a shear key and prevents axial loads from being transferred to the lower part of the shaft. The device works effectively in dry environments. DHC is not equipped to quantify verticality and base cleanliness. Therefore, no further evaluation of the device has been conducted in this study.

Source: www.gpe.org

Source: www.gpe.org

Source: www.gpe.org

(a) The Downhole Camera (DHC)

(b) DHC inside a shaft

(c) Sidewall irregularities

Figure 11. Photos. The Downhole Camera (DHC) System

In the next sections more information is presented for Mechanical Caliper, SHAPE, SQUID, Mini-SID, BIT, DID and SoniCaliper.

19

State DOT Tolerances A wide range of state DOT agency publications have been surveyed to study the variation of acceptable tolerances for shaft verticality and base cleanliness. Table 2 displays the findings from 17 states. In table 2, shaft center and top elevation tolerances are included in addition to verticality and base cleanliness tolerances. Although there are minor variations, the typical tolerances are:
Center of shaft is within 3 inches of plan location, Top of shaft is within 1 inch above and 3 inches below the elevation shown in the
plans, 1.5 percent to 2.0 percent of the total length for verticality and 50 percent of base shall have < inch of sediment, no area of the shaft base shall
be more than 1 inches for base cleanliness. Some states allow up to 6 inches of sediment thickness for skin friction shafts. The GDOT specifies a tolerance of 2 percent of the total length for verticality. Although no clear specifications are given for the base cleanliness in GDOT SP 524 Special Provisions, the general practice is a maximum of 1 inch for end bearing shafts and a maximum of 3 inches for skin friction shafts. Table 3 compares GDOT tolerances to typical state DOT tolerances.
20

Table 2. State DOT practice for shaft verticality and base cleanliness tolerances.

State AZ(19) CT(20)
FL(21)
GA(22) IL(23) KS(24) LA(25) MI(26)

Center of shaft
Within 3 inches of plan position in the horizontal plane. Within 3 inches of plan position in the horizontal plane.

Construction tolerance

Verticality

Top of shaft

NA

Plus 1 inch or minus 3 inches from the plan top-of-shaft elevation.

Within 3 inches of plan position in the horizontal plane.

No more than 1/4 inch per foot of depth.

Plus 1 inch or minus 3 inches from the top of shaft elevation shown in the plan.

Within 3 inches of

the plan position plane, at the topof-caisson

-inch per 12 inches of depth.

NA

elevation.

Within 3 inches of the plan station and offset at the top of the shaft.

1.5% of the total length.

No more than 1 inch above and no more than 3 inches below the plan elevation.

Within 2 inches of the plan location.
Within 3 inches of the plan station and offset at the top of the shaft.

The shaft must be plumb to within 1 inch in 10 feet of shaft length, not to exceed 6 inches.
Within 1.5% plumb.

NA
Within 2 inches of the top of the plan shaft elevation.

Within 3 inches of the centerlines shown on the plans at the topof-shaft elevation.

No more than 1% out of plumb.

Plus 1 inch to minus 3 inches from the top of the shaft elevation shown on the plans.

Base cleanliness
NA
NA
Minimum of 50 % of the base of each shaft will have less than 1/2 inch of sediment at the time of placement of the concrete. Maximum depth of sedimentary deposits should not exceed 11/2 inches.
NA
If terminated in soil, a maximum of 1 inches of sediment. If terminated in rock, a maximum of inch of sediment. 3/4 of the base of the socket will have less than inch of sediment.
NA
At least 50% of the base contains less than inch of sediment. The shaft base should have no more than 1 inches of debris above the required base elevation.

21

Table 2. (cont'd) State DOT practice for shaft verticality and base cleanliness tolerances.

State NC(27) NY(6) OH(28)
OR(29)

Center of shaft

Construction tolerance

Verticality

Top of shaft

Base cleanliness

Center of pier is within 3 inches of plan location.

Within 2% of plumb.

Within 1 inch above and 3 inches below the elevation shown in the plans or approved by the engineer.

At least 50% of base of holes has less than 0.5 inch of sediment and no portions of base of holes have more than 1.5 inches of sediment.

2% for vertical

NA

shafts 3% of the total shaft length for

NA

NA

battered shafts.

Within 3 inches No more than 1/4

of the plan

inch per foot of

NA

NA

location.

depth.

Shaft diameter less than or equal to 6 feet: 3 inches horizontal tolerance from the location shown. Shaft diameter greater than 6 feet: 6 inches horizontal tolerance from the location shown.

Vertical alignment in soil: May not vary from the plan alignment by more than 1.5 percent of the shaft length. Vertical alignment in rock: May not vary from the plan alignment by more than 2% of the shaft length.

Minus 3 inches to plus 1 inch from the plan top of shaft elevation.

End-bearing shaft: no more than 2 inches of loose or disturbed material. Side friction drilled shaft: no more than 6 inches of loose or disturbed material. Assume end-bearing shafts unless otherwise shown or specified.

SC(30)

Maximum location variance at top: 3 inches

Maximum: 1 inch per 4 feet

50% of base shall have < 1/2

NA

inch of sediment. No area of shaft base shall be more than

1 1/2 inches.

TN(31)

Within 3 inches of plans position in the horizontal plane at the plan elevation for the top of the shaft

Shafts in rock: no more than inch per foot of depth. Shafts in soil: no more than 3/16 inch per foot of depth.

Within a tolerance of 3/8 inch per foot of shaft diameter.

50% of the base of each shaft shall have less than inch of sediment at the time of concrete placement. The maximum depth of sediment or any debris at any place on the base of the shaft shall not exceed 1 inches.

22

Table 3. GDOT vs State DOTs, drilled shaft excavation tolerances.

Agency

Verticality

Base Cleanliness Reference

GDOT

2.0% of the total length (1/4 inch per 12 inches, 6mm per 305 mm).

Engineer's discretion1

GDOT SP 524 (Revised June 28, 2016)

State DOTs Typical

1.5% to 2.0% of the total length2

50% of base shall have < 1/2 inch of sediment. No area of shaft base shall be more than 1 1/2 inches3

Table 2

1. Current practice is a maximum of 1 inch for end bearing shafts and a maximum of 3 inches for skin friction shafts 2. 1.5% for sand, 2.0% for rock 3. Up to 6 inches for skin friction shafts

23

INSPECTION EQUIPMENT FOR VERTICALITY ASSESSMENT Mechanical Caliper Logging System The Mechanical Caliper Logging system is used to measure both verticality and shape profile of a drilled shaft. It is designed to operate in wet and dry environments. The mechanical caliper consists of two circular rings and four spring-loaded expanding arms, and cup (see figure 12).
Figure 12. Photo. Parts of mechanical caliper. Once calibrated at the top of the shaft, verticality is measured by bringing the rings in contact with side walls at certain depths as shown in figure 13. For calibration, the caliper is moved toward the inner wall, facing north, of the shaft near the top until both top and bottom rings are in contact with the wall. At this position, the gravity inclinometer sensor
24

is calibrated assuming the wall is vertical. Next, the caliper is lowered to the first data collection point. At this elevation, the caliper is moved to the center by simply pulling then releasing the cable at the top of the shaft. The caliper then makes a free swing, hits the wall and comes to a full stop on its own in a few seconds. The verticality is recorded, and the caliper is lowered to the next data collection point. The same steps are repeated at the other inner walls facing south, east and west.
Figure 13. Photo. Calibration of the caliper for verticality measurement. The shape of the shaft is evaluated by the extending arms. The arms are extended at the base of the shaft and the device is advanced slowly in an upward direction as shown in figure 14. The diameter of the shaft is measured as the caliper is moved from bottom to top with arms extended and touching the walls. Therefore, the caliper is lowered to the bottom
25

of the shaft first. Next, the cable is yanked firmly by the operator to release the arms from the cup. Once the arms are extended to the sides, the caliper is moved to the top slowly while the diameter data is collected continuously. The arm movements are recorded during this upward motion. It is important to note that the shape geometry is determined based on the data taken from the arm movements only. Therefore, the number of spring-loaded arms has significant impact on the accuracy of the shape assessment (12). All four arms are expected to work for a minimal level of accuracy.
Figure 14. Photo. Shape assessment with arms extended during upward motion. Unlike sonar methods, the mechanical caliper logging system is not affected by the density of the slurry and provides reliable calibration. It can be used for shafts up to 12 ft in diameter and 300 ft long. Table 4 shows highlights of this equipment including cost and vendor information.
26

Table 4. Highlights of Mechanical Caliper Logging system.

Vendor
Service Provider(s)
Transportation Mode Operating Environment Working Principle
ASTM DOT Experience Cost to Purchase Cost to Rent Cost of Training Cost of Full Service Link to Technical Specs Link to Sample Report Related Videos

Applied Foundation Testing 4035 J. Louis Street Green Cove Springs, Florida 32043 Phone: (904) 284-1337 https://testpile.com/service/caliper -logging-drilled-shafts/ Applied Foundation Testing 4035 J. Louis Street Green Cove Springs, Florida 32043 Phone: (904) 284-1337 https://testpile.com/ Contact Person: Andrew Best Large pickup truck
Wet and Dry Shafts
Mechanical arms touching walls and Accelerometer based inclinometer D8232-18
High
Contact service provider
Contact service provider
$1,000/day + travel, 2 days recommended Contact service provider
Click here
Click here
N/A
27

Shaft Area Profile Evaluator (SHAPE) SHAPE developed by Pile Dynamics, Inc. is ASTM D-8232 compliant, and equipped with transmitters and receivers that detect ultrasonic waves reflected from the side walls of the shaft. This device can only operate in wet environments and cannot be used for dry shafts. SHAPE consists of sonar sensors located at eight points around the perimeter, a computer inside the cylindrical chamber and a display unit that communicates with the computer. The device, attached to the Kelly bar as shown in figure 15, collects data continuously when lowered and raised inside the shaft.
Figure 15. Photo. SHAPE and its display unit before lowered into the shaft. 28

Once it is brought back to the surface, the data is then transferred to the display unit wirelessly. The shape profile becomes available immediately and is saved by the tablet computer display unit. Wireless data transfer is not available when the device is in water or slurry. The verticality is calculated as center deviation of the shape profiles divided by the distance between the two points. One useful advantage is that SHAPE can calibrate its sensors instantly. Transmitters and receivers are located at known intervals and the time is measured for ultrasonic waves to travel from one sensor to another. That way, wave velocity is computed and used to determine the distance from the sensors to the side walls. The accuracy of the shape assessment can be increased by rotating the Kelly bar at a constant rate, allowing data to be collected in every direction (12). Table 5 shows highlights of this equipment including cost and vendor information.
29

Table 5. Highlights of SHAPE.

Vendor
Service Provider(s)
Transportation Mode Operating Environment Working Principle ASTM DOT Experience Cost to Purchase Cost to Rent Cost of Training Cost of Full Service Link to Technical Specs Link to Sample Report Related Videos

Pile Dynamics 30725 Aurora Rd Cleveland, OH 44139 USA (216) 831-6131 www.pile.com Contact Person: Tom Tutolo GRL Engineers, Inc. Address: 2880 Cobblestone Dr. Cumming, GA 30041 Telephone: (678) 233-1435 Fax: (216) 831-0916 Email: GRL-GA@grlengineers.com Contact Person: Tom Hyatt Pickup truck
Wet shafts only
Ultrasound technology
D8232-18
High
Contact service provider
Contact service provider
Contact service provider
Contact service provider
Click here
Click here
Video 1
30

Borehole Inclination Tester (BIT) BIT is also ASTM D-8232 compliant and designed to assess only verticality of the shaft. BIT can operate in wet and dry environments. The main components of BIT are (1) main box, (2) inclinometer, (3) wireless depth meter, and (4) display unit as shown in figure 16.
Source: www.piletest.com Figure 16. Illustration. Components of Borehole Inclination Tester (BIT). Figure 17 shows the inclinometer attached to the drilling bucket (or auger) eliminating the need for additional centralizer equipment. However, it is not clear how the accuracy is affected compared to other devices that use a dedicated centralizer. As the inclinometer moves along with the bucket, it collects data continuously during both upward and downward motions. Verticality information becomes available on the display unit in real time.
31

Source: www.piletest.com Figure 17. Photo. Inclinometer attached to a bucket.
The vendor lists the following advantages of BIT on their website: Low-cost compared to traditional caliper systems Quick to test (minutes per borehole) User-friendly wizard-driven software. No training needed. Works on any diameter
Table 6 summarizes the highlights of BIT including cost and vendor information.
32

Table 6. Highlights of BIT.

Vendor
Service Provider(s) Transportation Mode Operating Environment Working Principle ASTM DOT Experience Cost to Purchase Cost to Rent Cost of Training Cost of Full Service Link to Technical Specs Link to Sample Report Related Videos

Piletest.com Limited 18 Fouracres Walk Hemel Hempstead Herts HP3 9LB United Kingdom www.piletest.com None Personal car Wet and Dry Shafts Inclinometer attached to drilling bucket D8232-18 None. Purchased by US contractors. $16,215 (includes shipping) NA NA NA Click here NA Video 1
33

SoniCaliper SoniCaliper, developed by LoadTest, Inc., uses a similar sonar technology with SHAPE. One major advantage of SoniCaliper compared to SHAPE is that SoniCaliper can collect ultrasonic data at 400 points along the perimeter of the shaft leading to a more accurate shape assessment, volume calculation, and verticality measurement. The SHAPE can collect sonar data only at eight points. The impact of number of data points on the crosssectional area of the shaft is shown in figure 18. The difference in calculated area between four data points and 300 data points is 16.7 percent. Additionally, SoniCaliper provides a true 3D shape profile output as an AUTOCAD drawing file.
Courtesy of LoadTest, Inc. Figure 18. Illustration. Sonar data points and calculation of shaft area.
34

The device is lowered into the shaft without the need for contractor drilling equipment as shown in figure 19. SoniCaliper is available for both dry and wet environments. Table 7 summarizes the highlights of SoniCaliper including cost and vendor information.
Source: www. Loadtest.com Figure 19. Photo. SoniCaliper lowered into the shaft.
35

Table 7. Highlights of SoniCaliper (Dry and Wet Sonars are available separately)

Vendor
Service Provider(s)
Transportation Mode Operating Environment Working Principle ASTM DOT Experience Cost to Purchase Cost to Rent Cost of Training Cost of Full Service
Link to Technical Specs Link to Sample Report Link to Sample Specifications Related Videos

Loadtest 2631-D NW 41st Street, Gainesville, Florida 32606 1 352 339-7708 www.loadtest.com Loadtest 2631-D NW 41st Street, Gainesville, Florida 32606 1 352 339-7708 Personal car
Wet and Dry Shafts (available in separate units) Ultrasound technology
D8232-18
Extensive
$89,850 (wet sonar only). Price for dry sonar not available yet. $3,500/mo or $250/shaft, whichever is greater $8,500 maximum two days, includes equipment mobilization $6,500 for day 1 including equipment mobilization $2,000 for each additional day Click here
Click here
Click here
N/A
36

INSPECTION EQUIPMENT FOR BASE CLEANLINESS Shaft Quantitative Inspection Device (SQUID) The SQUID is used to quantify the thickness of the sediment at the base of the shaft. The device can easily be attached to the Kelly bar as shown in figure 20 and it has three retractable plates that are pushed into the sediment to measure the penetration resistance.
Figure 20. Illustration. SQUID with retractable plates. 37

The sediment material is assumed to have a strength similar to soft-to-medium clay with an unconfined compressive strength range of 0.25 ksf to 2 ksf (3). In order to correlate this strength range to penetration resistance in force units, Terzaghi's bearing capacity formula for flat circular foundations, qult=1.3suNc is used. One can verify that the strength range for soft-to-medium clay corresponds to 0.020 kips to 0.160 kip of penetration resistance by using Terzaghi's bearing capacity equation. Therefore, the thickness of the sediment is calculated as the vertical displacement of the retractable plate when the penetration resistance changes from 0.020 kip to 0.160 kip. Any penetration resistance less than 0.020 kip is considered to be a material lighter than concrete that would be displaced upon concrete placement, and any resistance greater than 0.160 kip is assumed to be an indication of stiff clay or rock that would not have significant impact on the performance of the shaft. Figure 21 illustrates this process in a simple forcedisplacement graph. Table 8 summarizes the highlights of SQUID including cost and vendor information.
38

Figure 21. Illustration. Determination of sediment thickness using Terzaghi's bearing capacity formula.
39

Table 8. Highlights of SQUID

Vendor
Service Provider(s)
Transportation Mode Operating Environment Working Principle ASTM DOT Experience Cost to Purchase Cost to Rent Cost of Training Cost of Full Service Link to Technical Specs Link to Sample Report Link to Sample Specifications Related Videos

Pile Dynamics 30725 Aurora Rd Cleveland, OH 44139 USA (216) 831-6131 www.pile.com Contact Person: Tom Tutolo GRL Engineers, Inc. Address: 2880 Cobblestone Dr. Cumming, GA 30041 Telephone: (678) 233-1435 Fax: (216) 831-0916 Email: GRLGA@grlengineers.com Contact Person: Tom Hyatt Pickup truck
Wet and dry shafts
Retractable probes measure penetration resistance NA
High
Contact service provider
Contact service provider
Contact service provider
Contact service provider
Click here
Click here
Click here
Video 1
40

Ding Inspection Device (DID) DID was developed by John Z. Ding for measuring the sediment thickness at the base of a drilled shaft without human access into the excavation. The device is approximately 15 pounds and consists of a submersible waterproof measuring unit, a digital position sensor (Linear Variable Differential Transformer (LVDT) with 4-inch range), and a high-strength cable to carry and lower the measuring unit and to transfer the electrical signals from the digital sensor to the surface readout unit. A digital position sensor can typically sense a submillimeter position variation.
Source: www.dmy-inc.com Figure 22. Photos. Ding Inspection Device measuring sediment thickness.
The length of the high-strength cable can be adjusted to measure a drilled shaft up to 200 feet deep. In general, it takes less than 10 minutes for a trained technician or a field engineer to complete the measurement of the sediment thickness at the base of a drilled shaft. Laboratory model tests and field comparisons to Mini-SID have demonstrated repeatability and accuracy of sediment thickness measurements using the device(11). Since the device is only 15 pounds, it can be operated by a single field technician, significantly reducing the time required for sediment thickness measurement and
41

construction costs. The device is also much less expensive than other available devices. The existing DID is favorable for measuring the sediment thickness where the compositions of the slough are relatively uniform. When the slough has gravel and cemented particles of over three inches in diameter, a special DID set of larger leg spacing is required. Table 9 summarizes the highlights of DID including cost and vendor information.
42

Table 9. Highlights of DID

Vendor
Service Provider(s) Transportation Mode Operating Environment Working Principle ASTM DOT Experience Cost to Purchase Cost to Rent Cost of Training Cost of Full Service Link to Technical Specs Link to Sample Report Related Videos

DMY 14241 Midlothian Tpke, Suite 230 Midlothian, VA 23113 Phone: (804) 381-4800 Cell: (804) 955-9589 http://dmy-inc.com/did.php Contact Person: John Ding None Personal car, weighs 18 lbs Wet and dry shafts LVDT used to measure depth of leg penetration NA High $9,500 + tax NA NA NA Click here Click here Video 1
43

Shaft Inspection Device (Mini-SID) Mini-SID mainly consists of a diving bell and debris gages attached to the interior wall of the bell. A camera is also located inside the bell to monitor the base sediment and gages to visually determine the depth of sediment. The device is lowered into the shaft by its winching system as shown in figure 23.
Figure 23. Photo. Mini-SID diving bell lowered into the shaft via winching system. Once it is at the base, air pressure is applied into the bell and water is pushed out of the diving bell for a clear view of the gages. The gages are the 45o angle brackets (see figure 24) with color coded pins evenly spaced in a vertical direction to measure the sediment thickness. Measuring sediment thickness is partially subjective since the thickness data is collected visually through the camera located inside the diving bell and averaged. Sediment thickness conditions are not always uniform; gages may indicate different depths and
44

lumps may exist at random locations. In such cases, the thickness data is interpolated and averaged (16). Table 10 summarizes the highlights of Mini-SID including cost and vendor information.
Figure 24. Illustration. Mini-SID diving bell and sediment thickness gages.
45

Table 10. Highlights of Mini-SID

Vendor
Service Provider(s)
Transportation Mode Operating Environment Working Principle ASTM DOT Experience Cost to Purchase Cost to Rent Cost of Training Cost of Full Service Link to Technical Specs Link to Sample Report Related Videos

Applied Foundation Testing 4035 J. Louis Street Green Cove Springs, Florida 32043 Phone: (904) 284-1337 https://testpile.com/service/mini-sid/ Applied Foundation Testing 4035 J. Louis Street Green Cove Springs, Florida 32043 Phone: (904) 284-1337 Contact Person: Andrew Best ton pickup
Wet and dry shafts
Depth of bell penetration visually collected from color coded gages NA
High
$85,000 + tax, $2,500 for an additional monitor $1,750 + tax per week
$1,000/day + travel, 2 days recommended Contact service provider
Click here
Click here
NA

46

CHAPTER 3: FIELD DEMONSTRATION EVENTS
FIELD DEMONSTRATION #1: MECHANICAL CALIPER, SID, SHAPE, SQUID The second field demonstration event took place on November 3rd, 2020 in Hall County at Hwy 53 over Lake Lanier. The approximate location of the drilled shaft project is shown in figure 25. Applied Foundation Testing (AFT), Pile Dynamics, Inc. (PDI) and GRL Engineers, Inc. participated with a total of four types of inspection equipment:
Mechanical Caliper, SID, SHAPE and SQUID. The entire field event took about 6.5 hours. All four pieces of equipment were shipped to the site the day before and loaded to the barge by the drilling contractor on the day of the field demonstration. Shaft 1 of Bent 3 (see figure 26) was selected for this field demonstration. The shaft was approximately 112 ft long (cased 102 ft and uncased 10 ft), 6 ft wide and filled entirely with fresh water. According to the boring log in figure 27, the rock formations starts at about 6 ft below the lakebed. In the next sections, the field operating conditions and equipment effectiveness are discussed.
47

Figure 25. Illustration. The location of the second field demonstration event.
Figure 26. Photo. Bent 3, Shaft 1. 48

Figure 27. Chart. Boring log at SR53 Bent 3 49

Mechanical Caliper The mechanical caliper operation requires three people as shown in figure 28. The mechanical caliper is lowered into the shaft with the help of the data cable and winch. The data cable is supported by a single pulley attached to the drilling equipment. One person stands next to the shaft and monitors the caliper, the second person operates the winch, and the third person monitors the tablet PC for data collection.
Figure 28. Photo. Mechanical Caliper Logging system during field operation. Shaft inspection procedure is conducted in two parts:
Part 1 Verticality measurement: The deviation profile is created in all directions as shown in figure 29. The verticality is computed as the maximum deviation divided by the length of the shaft. For this example, the maximum deviation is 6 inches and the shaft length is 100 ft resulting a verticality of 0.45 percent. The red line on the left is the tolerance limit corresponding to 2 percent verticality. 50

Figure 29. Graph. Deviation profile and the criteria.
Part 2 Diameter measurement: The results are presented in a diameter profile plot (see figure 30), and a shape profile graph (see figure 31).
The straight line in figure 30 represents a constant diameter of 72 inches for the first 102 ft confirming the 102 ft casing. The dark lines in figure 31 indicate sections with a changing diameter, and the color red represents sections where the diameter is constant.
During the field demonstration, both parts were completed in less than one hour. Minor delays were encountered but were resolved quickly. The full inspection report is available in Appendix B.
Pros and cons of the Mechanical Caliper are summarized in table 11. 51

` Figure 30. Graph. Diameter profile.

Figure 31. Graph. Shape profile.

Table 11. Field effectiveness summary for Mechanical Caliper: Pros and Cons

Pros

Cons

Operates in wet and dry conditions. Heavy equipment. Needs a large pickup

Not affected by the density of slurry. truck for transportation.

Can be completed in less than one Pricing information was not available at

hour.

the time of field demonstration.

Diameter data is collected

3D shape profile is not available.

continuously.

Diameter is measured only at extending

Verticality and diameter data are

arm-wall contact points.

available immediately.

Extending arms may get stuck.

Requires personnel near open excavation.

52

Shaft Inspection Device (SID) Figure 32 shows the Mini-SID setup used during the field demonstration. The control unit on the right houses all components: diving bell, winch, power generator and display units. This device requires two people to operate: the winch operator and data collector. The diving bell is positioned at the north side of the shaft and lowered to the bottom immediately. Once the diving bell is at the bottom, the operator sends air into the bell to expel water so that a clear view of the bottom and sediment gages can be obtained. The camera inside the bell records the entire process as a video. Still pictures can also be taken using the touch screen of the display unit. The diving bell is moved to south, east, west and center locations at the base for more sediment thickness measurements.
Figure 32. Photo. Mini-SID during field operation.
53

The sediment thickness is quantified through a visual inspection of the sediment and gages (45o angle brackets with color-coded and evenly distributed pins) at the bottom. Figure 33 shows one of the still pictures taken at four locations at the base. The yellow pin is at 1.0 inches and the red (top) pin is at 1.5 inches. The sediment thickness shown in figure 33 is less than 1.0 inch. Finally, the sediment thickness values are entered into the one-page report template. A one-page inspection report is provided in Appendix B.
Figure 33. Photos. Sediment thickness measurement. Pros and cons of the Mini-SID are summarized in table 12.
54

Table 12. Field effectiveness summary for Mini-SID: Pros and Cons

Pros

Cons

Operates in wet and dry conditions.

Heavy equipment. Needs a large pickup

Not affected by the density of slurry.

truck for transportation.

Can be completed in less than one hour. The winch cable requires attention to

Data is available immediately.

prevent tangling.

Camera provides a visual assessment of Readings can be subjective.

the sediment.

Additional monitor allows observers to

see the video.

55

Shaft Area Profile Evaluator (SHAPE) The SHAPE weighs about 100 lb and is very easily attached to the Kelly bar. Eight sonar receivers and eight transmitters are at the bottom as shown in figure 34. The display unit is a tablet computer used to transfer data wirelessly from the device. The cylinder directly above the sensors is the housing unit for the internal computer to collect data during the operation.
Figure 34. Photo. SHAPE and its display unit. Once attached to the Kelly bar, the SHAPE is directly lowered into the shaft without making any stops. Since the device is not designed to withstand significant force, it is important to stop the advancement of the device before it touches the base. For that reason, a measuring tape is attached to the device during operation to monitor the depth.
56

The SHAPE collects data during both downward and upward motion. It sends the shape and verticality data to the display unit as soon as it returns to the ground surface. The data is processed, and shape profiles are made available immediately. During this field demonstration, no delays were encountered, and the inspection was completed in less than 30 minutes. Pros and cons of the SHAPE are summarized in table 13.

Table 13. Field effectiveness summary for SHAPE: Pros and Cons

Pros Wave velocity calibration done

Cons Operates in wet environments only.

internally. Easy to attach.

Shape data collected at sensor locations, 45o apart, only.

Easy to operate.

Not designed to withstand heavy loads

Wireless communication between

from the Kelly bar.

SHAPE and the display unit.

Once attached, it takes 15 min to

complete.

Data available immediately.

Not too large, fits in a small pickup

truck.

Reliable sonar technology.

57

Shaft Quantitative Inspection Device (SQUID) The SQUID weighs 415 lb and is attached to the Kelly bar of the drilling equipment. It is attached to the display unit with a data cable as shown in figure 35. Unlike SHAPE, a wired connection is used for the data transfer. A wired connection is essential since Bluetooth devices may not work when the device is in deep water. A wired connection allows engineers to see the penetration resistance data in real time and make decisions to repeat the test when errors occur. In addition to the data cable, a measuring tape is also attached to the device for depth monitoring purposes.
Figure 35. Photo. Preparing SQUID for base cleanliness assessment. 58

The device is moved to five different points at the base to collect penetration resistance data: north, south, east, west and center. Since it has three retractable probes located at the bottom of its legs, a total of 15 penetration data sets are collected during the process. Figure 36 illustrates the data collection scheme for SQUID.

Figure 36. Illustration. Data collection at the shaft base using SQUID.

The penetration data is processed as explained in figure 21 to determine the sediment thickness and results are summarized in table 14. In this field demonstration, the average sediment thickness was around 0.45 inches. Pros and cons of the SQUID are summarized in table 15.

Table 14. Summary of sediment thickness using SQUID.

Shaft number
Bent 3 Shaft 1

Date

Time

Test

completed location

11/3/2020 10:56:47

Center South North East West

Sediment thickness (in.)

Probe number

30003DC 30005DC 30004DC

N/A

0.35

0.52

0.35

0.45

0.61

0.24

0.56

0.53

0.21

0.21

0.59

N/A

0.06

0.06

Average all probes
0.44 0.47 0.44 0.34 0.40

59

Table 15. Field effectiveness summary for SQUID: Pros and Cons

Pros

Cons

Operates in wet and dry environments. Weighs 415 lb.

Easy to attach.

Easy to operate.

Takes less than 30 min to complete.

Data available immediately.

Fits in a small pickup truck.

Designed to withstand heavy loads from

the Kelly bar.

60

FIELD DEMONSTRATION #2: DID The third field demonstration event was conducted at County Road 808 over Dog River (see figure 37). DMY, Inc. was the only participant using a DID to quantify base sediment thickness. The DID weighs about 18 lb and fits in a small protective box. Along with its cable, it can be stored and transported conveniently.
Figure 37. Illustration. Location of the third field demonstration event. The device is lowered into the shaft manually by a single person as shown in figure 38. The displacement of the bottom plate is measured by the LVDT located at the center of the device (see figure 22) and displayed on the digital readout in millimeters (see figure 39). The device is moved to five different locations (north, south, east, west, and center) by the same operator to measure the thickness of the sediment. However, for shafts with large diameters, moving the device to the center can be challenging and dangerous for the operator. In such cases, an extension rod (see figure 40) is used to center the device safely.
61

Figure 38. Photo. DING inspection device operated by one person.
Figure 39. Photo. Digital readout for the DING inspection device. 62

Figure 40. Photo. Extension rod for DING inspection device. The sediment thickness data is presented in table 16. During this field practice, two shafts were assessed for base cleanliness.

Drilled shaft ID
#1 #2

Table 16. Sediment thickness data using DID. Measured sediment thickness (mm)

North

East

South

West

Center

12

11

12

8

18

7

12

10

10

25

Average sediment thickness
(mm)
12
13

Pros and cons of the DID are summarized in table 17.

63

Table 17. Field effectiveness summary for DID: Pros and Cons.

Pros

Cons

Operates in wet and dry environments. No camera available.

Light weight.

Can be operated by one person.

Easy to operate.

Takes less than 15 min to complete.

Data available immediately.

Affordable.

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CHAPTER 4: CONCLUSIONS
A range of drilled shaft excavation inspection methods with the capability to eliminate sending a human into the dry shaft excavation has been evaluated. Several equipment types were evaluated during field demonstration events to observe their field effectiveness. It appears that verticality and base cleanliness assessment methods and quantitative equipment types are limited in number. While there is no ASTM standard for base cleanliness testing methods, a new ASTM standard D8232-18, which still lacks precision recommendations, was published for verticality assessment in 2018. All recommended verticality equipment types in this report are in compliance with the new standard. In summary, a total of six quantitative methods have been identified as suitable to evaluate the verticality and base cleanliness of dry shafts. The equipment pieces, three for verticality and three for base cleanliness, are listed in table 18 and table 19 as a quick reference in this chapter. In order to assist GDOT Geotechnical Bureau in facilitating engineering decisions in selecting a dry shaft excavation inspection method, the followings resources and guidelines are provided in this report:
Highlights tables summarizing the relevant aspects of each inspection equipment including vendor, cost, mobility, ASTM compliance, related publications, working principles and working environments. (Chapter 2).
Pros & cons tables according to the field effectiveness (Chapter 3). Summary of final recommendations in order of preference based on
six criteria (Chapter 5).
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Table 18. Equipment suitable for dry shaft base cleanliness assessment.

Equipment

DID

SQUID

Mini-SID

Image

Table 19. Equipment suitable for dry shaft verticality assessment.

Equipment

BIT

Mechanical Caliper

SoniCaliper

Image

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CHAPTER 5. RECOMMENDATIONS
Based on the information collected during the literature review efforts and field demonstration observations, the inspection equipment selection recommendations were made in table 20 using the following six criteria:
Safety: This criterion is used based on the number of personnel needed during the setup over the shaft hole and near the excavation during operation. No OSHA criteria were used to evaluate the methods.
Cost: Only the cost to purchase was considered. Not all vendors provided cost to lease and cost for training. It should be noted that all pricing information is subject to change and the vendors must be contacted for an up-to-date quote.
Mobility: Size and weight information have been considered for mobility. Accuracy: Number of data collection points and the data precision were considered. Speed: Time needed to complete one shaft inspection was considered. State DOT experience: The number of state DOTs that purchased the equipment or
received direct service was collected informally from the vendors. Published work citing state DOT affiliation or collaboration was also considered. No formal survey was conducted among the state DOTs or technology vendors. Table 20 lists the equipment types in the order of preference for each criterion based on professional judgement and in no way indicates pass of fail. This table was intended to serve as a guideline for GDOT personnel in making dry shaft excavation inspection equipment selection decisions. The following are recommended for future studies concerning dry shaft inspection equipment selection and beyond:
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Conduct a formal survey among state DOTs to better understand the current state of inspection practice.
Conduct a feasibility study to create guidelines for decision making between purchasing and leasing.
Conduct controlled field tests with baseline data to assess the reliability of inspection equipment.
Revisit each inspection procedure in the field to recommend safety improvements based on OSHA requirements.
Collaborate with vendors to develop a single device that can assess both verticality and base cleanliness.
Collaborate with vendors to improve their existing technology. Extend this research to wet shafts and study the impacts of construction methods on shaft
excavation inspection techniques. Study the impact of silt content on ultrasound measurements in wet shafts.
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Table 20. Final recommendations in the order of preference for verticality and base cleanliness equipment for dry shafts.

Safety SHAPE**

Cost BIT

Verticality Equipment*

Mobility

Accuracy

Speed

BIT

SoniCaliper SHAPE

DOT Experience
SoniCaliper

SHAPE,

BIT

SoniCaliper SoniCaliper

SHAPE

BIT***

Mechanical

Caliper

SoniCaliper

SHAPE+
Mechanical Caliper+

SHAPE

Mechanical Caliper

SoniCaliper*** BIT

Mechanical Caliper

Mechanical Caliper

BIT

Mechanical Caliper

* All but SHAPE can operate in wet and dry environments. All conform to ASTM D8232-18. ** The SHAPE works in wet environments only. It is included here since the device was used in one
of the field demonstrations to represent sonar technology.
***Estimated, not observed in the field. +Estimated. Call vendor for more info.

Base Cleanliness Equipment++

Safety

Cost

Mobility

Accuracy

Speed

DOT Experience

SQUID

DID

DID

SQUID

DID

Mini-SID

Mini-SID

Mini-SID

SQUID

DID

SQUID

SQUID

DID

SQUID+++

Mini-SID

Mini-SID

Mini-SID

DID

+ All devices can operate in wet and dry environments. No ASTM standard available. +++Estimated. Call vendor for more info. Criteria: Safety: Personnel required near shaft excavation during setup or operation. Cost: Cost to purchase. Mobility: Size and weight. Accuracy: Number of data points, precision. Speed: Time to complete one shaft inspection. DOT Experience: Number of DOTs purchased or received direct service.

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APPENDIX A: TECHNICAL SPECS 70

SHAFT AREA PROFILE EVALUATOR (SHAPE) 71

SHAFT QUANTITATIVE INSPECTION DEVICE (SQUID) 72

73

DING INSPECTION DEVICE 74

MECHANICAL CALIPER 75

SHAFT INSPECTION DEVICE (MINI-SID) 76

77

SONICALIPER 78

BOREHOLE INCLINATION TESTER (BIT) 79

APPENDIX B: SAMPLE INSPECTION REPORTS 80

SHAFT AREA PROFILE EVALUATOR (SHAPE) 81

82

83

84

85

86

87

88

89

90

91

92

93

94

SHAFT QUANTITATIVE INSPECTION DEVICE (SQUID) 95

96

97

98

99

100

101

102

103

104

105

106

107

MECHANICAL CALIPER 108

109

110

111

112

113

114

115

116

SHAFT INSPECTION DEVICE (MINI-SID) 117

DING INSPECTION DEVICE 118

119

120

SONICALIPER 121

122

123

124

125

126

127

128

129

APPENDIX C: SAMPLE CONTRACT SPECIFICATIONS 130

DRILLED SHAFT BASE CLEANLINESS USING SQUID
In using this sample specification, it should be recognized that each site and structure is unique. Therefore, geotechnical judgment based upon knowledge of the local soil conditions and deep foundation installation practice should be used to modify this sample specification to address the requirements of a specific project.
SECTION 1.0 GENERAL
1.01 Summary of Work
The (Engineer, Specialty Testing Consultant, Quality Control Agency, or Contractor) shall perform drilled shaft base cleanliness tests prior to concrete placement. The base cleanliness tests shall be performed no later than ___ (generally 2 hours or less) prior to commencing the shaft concrete pour.
Note: The time allotted between testing and concrete placement is very important. Longer times can allow additional material to settle out of the drilling slurry and accumulate at the shaft base. Longer times may also allow possible degradation of the bearing material such as in shales. The specifying engineer shall consider the potential deterioration of the slurry, the nature and potential degradation of the soil/rock conditions, the time necessary to transition to concrete placement procedures, and the availability of timely concrete delivery in selecting the maximum allowable time between base cleanliness testing and commencement of concrete placement.
1.02 Base Cleanliness Equipment
A Shaft Quantitative Inspection Device (SQUID) shall be used to assess the drilled shaft base cleanliness. The device shall record and provide information regarding the drilled shaft base cleanliness upon completion of the drilling and cleaning process. The device shall include the following components:
SQUID Unit. Unless updated by the equipment manufacturer, the SQUID Unit shall be a hexagonal shaped device with a height of approximately 25 inches (630 mm), a diagonal of approximately 26 inches (650 mm), and a weight of approximately 415 lbs (188 kg). The unit shall include three penetrometers each having a surface area of 1.55 in2 (10 cm2) to measure force and three displacement plates each having a diameter of 6 inches (152 mm) and a weight of 14.9 lbs (7.75 kg) to determine displacements. The unit shall also be supplied with two downhole data transmission cables and two transmitter boxes for signal conditioning.
Note: Two downhole transmission cables and two transmitters are specified so that spare equipment is readily available. Only one downhole data transmission cable and one transmitter box is required to perform the test.
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Kelly Bar Adapter. Drill rig Kelly bar dimensions vary depending upon the manufacturer and require an adapter to attach to the SQUID unit. For each drilling rig on the project, the contractor shall submit a completed Figure 1 to the SQUID equipment supplier two weeks prior to installing the initial drilled shaft with that drill rig.
Note: Kelly bar adapters for a specific drill rig may require longer delivery time if the required adapter is not readily available or previously manufactured. Therefore, the Contractor should consult the SQUID manufacturer or test supplier on specific adapter availability as soon as the drill rig is determined.
SQUID Tablet. The SQUID Tablet shall have a sunlight readable display screen with a minimum screen resolution of 1024 x 768. The SQUID computer tablet shall provide numerical and graphical display of all penetrometer and displacement plate results as well as a minimum 60 GB of internal memory storage. The Tablet shall also be capable of remote operation via a high speed internet connection.
The SQUID system is manufactured by Pile Dynamics, Inc., 30725 Aurora Road, Cleveland, OH 44139, USA. The manufacturer can be contacted at www.pile.com/pdi; email: info@pile.com; phone: +1 216-831-6131; fax +1 216-831-0916.
SECTION 2.0 - TEST PROCEDURE
2.01 General Procedure
The SQUID Unit shall be pin-connected to the Kelly bar using a properly sized adapter provided by the SQUID equipment supplier or contractor. After the pin-connection and prior to testing, the verticality of the SQUID Unit shall be checked and confirmed. The signal transmission from the SQUID Unit to the SQUID Tablet shall also be confirmed prior to commencing the test. Signal transmission shall be checked by manually lifting each displacement plate and observing the increasing displacement on the SQUID Tablet. After verticality and signal transmission checks are completed, the SQUID Unit shall be moved over the open shaft excavation and lowered without rotation until the unit is approximately 2 feet (0.6 m) above the shaft base.
The test shall proceed by slowly lowering the Kelly bar without rotation until the entire weight of the Kelly bar is transferred to, and is resting on, the SQUID Unit. Penetrometer force and plate displacement measurements shall be continuously acquired, displayed, and stored on the SQUID Tablet during the test process. A test run shall be terminated once two of the three penetrometers have registered a force greater than 0.5 kips (2.2 kN) or the maximum penetrometer travel of 6 inches (152 mm) is reached for any one of the penetrometers.
2.02 Shaft Base Diameters of Three Feet (0.9 m) or Less
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If the shaft base diameter is three feet or less, a single SQUID run shall be performed at the shaft center. The force versus displacement results from a minimum of two penetrometers shall be used to determine if the drilled shaft base condition meets the specified base cleanliness criteria or whether additional cleaning and retesting is required.
2.03 Shaft Base Diameters Greater than Three Feet (0.9 m)
If the shaft base diameter is greater than three feet (0.9 m), SQUID runs shall be performed in the center of the shaft as well as in the four quadrants surrounding the shaft center. The SQUID Unit shall be repositioned in one of the four perimeter quadrants (North, South, East, or West) around the shaft center and the process described above in Section 2.01 repeated. For each SQUID run, the average debris thickness determined using the force versus displacement results from a minimum of two penetrometers shall be used to determine if the drilled shaft base condition meets the specified base cleanliness criteria or whether additional cleaning and retesting is required.
SECTION 3.0 BASE CLEANLINESS CRITERIA
Note: Base cleanliness criteria are frequently specified on drilled shafts since base cleanliness influences the obtained end bearing resistance, the shaft deformation under applied loads, as well as the overall concrete quality of the completed drilled shaft.
3.01 Thickness of Sediment, Loose Material, or Debris
Sediment, loose material, or debris at the base of the shaft is defined as a material that has a minimum resistance to penetrometer force of ____ (generally 0.020 kips or 0.089 kN). Natural soils are defined as materials that have a resistance to penetrometer force greater than ____ (generally 0.160 kips or 0.71 kN). The thickness of sediment, loose material, or debris at the base of the drilled shaft is defined as the difference in the displacement plate measurements that occurs between a penetrometer force of ____ (generally 0.020 kips or 0.089 kN) to ____ (generally 0.160 kips to 0.71 kN).
Note: Materials having a resistance to penetrometer force less than 0.020 kips (0.089 kN) should have a unit weight less than 150 lb/ft3 (24 kN/m3). This softer material should be easily displaced by the concrete during concrete pouring process. Materials with resistance to penetration force values greater than 0.160 kips (0.71 kN) are considered natural soils or geomaterials. These penetrometer force threshold limits have been suggested based on experience but can be adjusted by the Engineer of Record if warranted by the subsurface material properties and conditions.
3.02 Limits of Debris Area
A drilled shaft base often contains irregularities from a level surface due to pilot holes or grooves from cutting teeth on drilling tools. Therefore, a SQUID run shall be considered
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complete provided the debris thickness can be determined from a minimum of two force versus displacement plots. A minimum of 50% of the drilled shaft base area shall have a debris thickness less than ___ inch (___mm) and the maximum debris thickness at any location shall not exceed ___ inches (___ mm).
Note: For shafts that rely significantly on the base resistance for load support, the debris thickness at the base of the shaft is often limited to inch (12 mm) over less than 50% of the base area with a maximum debris thickness in any location of 1.5 inches (38 mm).
SECTION 4.0 REPORTING
SQUID test results shall be reviewed by qualified personnel on-site or remotely connected by the internet to the SQUID unit prior to removing the SQUID unit from the drilled shaft excavation. Within one hour of completing the base cleanliness tests, a base cleanliness field report shall be submitted to the Engineer of Record for the tested drilled shaft. As a minimum, the base cleanliness field report shall include the approximate location of the tests, the test date and time, a plot of the penetrometer force versus plate displacement for each SQUID run, the calculated debris thickness, and whether the shaft base cleanliness meets the specification requirements.
Once per month, or upon completion of various project or testing phases, a formal report shall be prepared and submitted to the Engineer of Record summarizing the test results for all shafts in a given foundation unit or area. This report shall be submitted no later than ___ (ten) working days after the completion of the reported phase of testing.
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135

DRILLED SHAFT VERTICALITY AND PROFILE USING SONICALIPER 136

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ACKNOWLEDGEMENTS The authors would like to thank Michael Murray and Brennan A. Roney of GDOT for their support and assistance during various stages of the project, Mary Cooley and Demetrius Moton for their assistance during field demonstrations, and Adebola Adelakun and Catherine Armstrong for proving valuable insights into the project. The authors would also like to thank Tom Hyatt, Tom Tutolo, Andrew Best, Donald Robertson, John Ding, Nicole Gayotin, Ken Herzer, Joram Amir, Sean Flynn and Bill Ryan for conducting the field demonstrations and proving equipment information. Finally, the guidance of Dr. David K. Crapps and William (Bubba) Knight throughout this research project is sincerely acknowledged and appreciated.
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REFERENCES

1. ASTM. (2018). ASTM D8232-18, Standard Test Procedures for Measuring the Inclination of

Deep Foundation, West Conshohocken.

2. Brown, D. A., Turner, J. P. Castelli, R. J., and Loehr, E. J. (2018). Drilled Shafts: Construction

Procedures and Design Methods, FHWA-NHI 18-024, Federal Highway Administration,

Washington, D.C.

3. Moghaddam, R. B., Hannigan, P. J. and Keith, A. (2018). Quantitative Assessment of Drilled

Shafts Base-Cleanliness Using the Shaft Quantitative Inspection Device (SQUID). IFCEE

2018: Installation, Testing, and Analysis of Deep Foundations, Orlando, FL.

4. Turner, J. P. (2006). Rock-Socketed Shafts for Highway Structure Foundations. National

Cooperative Highway Research Program (NCHRP) Synthesis 360, Transportation Research

Board, National Research Council.

5. Florida Department of Transportation. (no date). "Drilled Shaft Inspector Course CBT."

(website) Tallahassee, FL. Available online: http://wbt.dot.state.fl.us/, last accessed January

04, 2021

6. New York Department of Transportation. (2015). New York Department of Transportation.

Drilled Shaft Inspector's Guidelines. GEM-18, New York Department of Transportation,

Albany, NY.

7. Kansas State University. (2020). "Drilled Shaft Inspection Workbook - Certified Inspector

Training Program." (website) Kansas State University Polytechnic Campus, Salina, KS.

Available online: https://polytechnic.k-state.edu/research-training/training-professional-

development/certified-inspector-training/documents/workbook/drilled-shaft-inspection-

workbook.pdf, last accessed January 04, 2021

8. Oregon Department of Transportation. (2019). Drilled Shaft Inspector Training Manual,

Oregon Department of Transportation., Salem, OR.

9. North Carolina Department of Transportation. (2015). "Sounding Drilled Shafts for

Cleanliness."

(website)

Raleigh,

NC.

Available

online:

https://www.youtube.com/watch?app=desktop&v=G7CMTolGXDA, last accessed January

04, 2021

10. Ding, J. (2012). Ding Inspection Device User's Manual. DMI Incorporation, Midlothian, VA.

139

11. Ding, J. Z., McIntosh, K. A., Simon, R. M. (2015). New device for measuring drilled shaft bottom sediment thickness, The Journal of the Deep Foundations Institute, Vol. 9, pp. 42-47.
12. Moghaddam, R., Belardo, D. S., Piscsalko, G., and Likins, G. (2019). Quality Control of Drilled Foundations for Base Cleanliness, Concrete Integrity, and Geometry, 10th International Conference on Stress Wave Theory and Testing Methods for Deep Foundations. San Diego, CA
13. Brown, D., (2002). Effect of Construction on Axial Capacity of Drilled Foundations in Piedmont Soils, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 128 (12), pp. 967-973.
14. Isenhower, W. M. (2005). Practical Considerations for the Design of Drilled Shaft Foundations. Geo-Frontiers Congress 2005, Austin, TX. 2005, pp. 130-142.
15. Piscsalko, G., Likins, G., and White, B. (2013) Non-Destructive Testing of Drilled Shafts Current Practice and New Method, 30th International Bridge Conference, Pittsburgh, PA
16. Camp, W.M., Brown, D. A., and Mayne, P. W. (2002). Construction Method Effects on Axial Drilled Shaft Performance, Deep Foundations 2002: An International Perspective on Theory, Design, Construction, and Performance. pp. 193-208.
17. Turner, J. P. (1992). Constructability for Drilled Shafts, Journal of Construction Engineering and Management. Vol. 108 (1). pp. 77-93.
18. PileTest, Inc., (no date). "BIT User's Manual version 3.1." (website) Hertfordshire, United Kingdom, Available online: https://www.piletest.com/show.asp?id=BIT_User_Manual, last accessed January 17, 2021
19. Arizona Department of Transportation. (2005). Construction Manual Section 609 Drilled Shaft Foundations, Arizona Department of Transportation. Phoenix, AZ.
20. Connecticut Department of Transportation. (2015). Supplemental Specifications to the Standard Specifications for Roads, Bridges and Incidental Construction Form 816, Section 7.01, Connecticut Department of Transportation. Newington, CT.
21. Florida Department of Transportation. (2018). Standard Specifications for Road and Bridge Construction, Section 455, Structural Foundations, Florida Department of Transportation. Tallahassee, FL.
22. Georgia Department of Transportation. (2016). Special Provision, Section 524, Drilled Caisson Foundations, Georgia Department of Transportation. Atlanta, GA.
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23. Illinois Department of Transportation. (2016). Standard Specification, Section 516, Drilled Shafts, Georgia Department of Transportation. Springfield, IL.
24. Kansas Department of Transportation. (2008). Bridge Construction Manual, Section 5.0, Drilled Shafts, Kansas Department of Transportation. Topeka, KS.
25. Louisiana Department of Transportation and Development. (2002). Drilled Shaft Foundation, Construction Inspection Manual, Louisiana Department of Transportation and Development. Baton Rouge, LA.
26. Michigan Department of Transportation. (2012). Standard Specifications for Construction, Section 718, Drilled Shafts, Michigan Department of Transportation. Lansing, MI.
27. North Carolina Department of Transportation. (2014). Construction Manual, Section 411, Drilled piers, North Carolina Department of Transportation. Raleigh, NC.
28. Ohio Department of Transportation. (2013). Manual of Procedures (MOP) Item 524, Drilled Shafts, Ohio Department of Transportation. Columbus, OH.
29. Oregon Department of Transportation. (2018). Standard Specifications for Construction, Section 00512 - Drilled Shafts, Oregon Department of Transportation. Salem, OR.
30. South Carolina Department of Transportation. (2002). Drilled Shaft Inspection Log, South Carolina Department of Transportation. Columbia, SC.
31. Tennessee Department of Transportation. (2017). Special Provision 625, Drilled Shaft Specification, Tennessee Department of Transportation. Nashville, TN.
32. Texas Department of Transportation. (2014). Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges. Item 416, Drilled Shaft Foundations, Texas Department of Transportation. Austin, TX.
33. Washington State Department of Transportation. (2020). Standard Specifications for Road, Bridge, and Municipal Construction, M 41-10, Section 6.19, Shafts, Washington State Department of Transportation. Olympia, WA.
34. Wisconsin Department of Transportation. (2018). Special Provision 0090 Drilled Shafts, Wisconsin Department of Transportation. Madison, WI.
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