AZ L-65 Drilled Piers Contractor Exam
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Answers) Plus Rationale 2027 Q&A| Instant
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1. What is the primary purpose of a drilled pier?
a. To provide temporary access for excavation
b. To transfer structural loads into competent subsurface materials
c. To eliminate the need for reinforcement
d. To reduce the concrete curing period
Answer: b. To transfer structural loads into competent subsurface
materials
Rationale: A drilled pier is a deep foundation element designed to
transfer structural loads through weak or compressible near-surface
soils to stronger soil or rock at greater depth. Load transfer may occur
through end bearing, side resistance, or a combination of both.
, 2. Which soil condition generally presents the greatest concern for
maintaining an open drilled-pier excavation?
a. Dense, dry gravel
b. Massive competent rock
c. Loose, saturated granular soil
d. Hard, intact limestone
Answer: c. Loose, saturated granular soil
Rationale: Loose saturated granular soils can readily slough or
collapse into an open excavation. Groundwater reduces effective
stress and can cause instability, making casing, slurry, or another
excavation-support method necessary.
3. What is the primary function of temporary casing during drilled-
pier construction?
a. Increase concrete strength
b. Prevent the excavation walls from collapsing
c. Replace reinforcing steel
d. Reduce the pier diameter
Answer: b. Prevent the excavation walls from collapsing
Rationale: Temporary casing supports unstable excavation walls and
can also help control groundwater and prevent loose material from
,entering the hole. It is removed as concrete is placed when the
construction method calls for casing extraction.
4. Before drilling begins, what should be verified regarding
underground utilities?
a. Only electrical utilities
b. Only water lines
c. The location of known and potentially affected underground utilities
d. Only utilities shown on the contractor's equipment drawings
Answer: c. The location of known and potentially affected
underground utilities
Rationale: Drilling equipment can encounter buried electrical, gas,
communications, sewer, and water facilities. Utility locating and
appropriate verification are essential before excavation begins to
prevent service damage, injury, and project delays.
5. What is a common method for keeping the walls of an unstable
drilled excavation open without permanent casing?
a. Dry sand placement
b. Stabilizing drilling slurry
c. Removing all reinforcement
d. Reducing the excavation depth
, Answer: b. Stabilizing drilling slurry
Rationale: Drilling slurry can exert hydrostatic pressure against the
excavation walls, helping prevent caving and reducing groundwater
intrusion. Proper slurry properties and maintenance are essential for
the method to work effectively.
6. In drilled-pier construction, what does the term "socket"
commonly refer to?
a. A threaded connection in reinforcing steel
b. A portion of the pier drilled into competent rock
c. The concrete placement tremie
d. The top of the reinforcing cage
Answer: b. A portion of the pier drilled into competent rock
Rationale: A rock socket is a drilled portion of a pier extending into
competent rock. It may be used to develop significant axial or lateral
resistance through sidewall bond, end bearing, or both, depending on
design.
7. Why is the bottom of a drilled excavation cleaned before concrete
placement?
a. To increase excavation diameter
b. To remove loose cuttings and debris that could compromise the
Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A| Instant
Download Pdf
1. What is the primary purpose of a drilled pier?
a. To provide temporary access for excavation
b. To transfer structural loads into competent subsurface materials
c. To eliminate the need for reinforcement
d. To reduce the concrete curing period
Answer: b. To transfer structural loads into competent subsurface
materials
Rationale: A drilled pier is a deep foundation element designed to
transfer structural loads through weak or compressible near-surface
soils to stronger soil or rock at greater depth. Load transfer may occur
through end bearing, side resistance, or a combination of both.
, 2. Which soil condition generally presents the greatest concern for
maintaining an open drilled-pier excavation?
a. Dense, dry gravel
b. Massive competent rock
c. Loose, saturated granular soil
d. Hard, intact limestone
Answer: c. Loose, saturated granular soil
Rationale: Loose saturated granular soils can readily slough or
collapse into an open excavation. Groundwater reduces effective
stress and can cause instability, making casing, slurry, or another
excavation-support method necessary.
3. What is the primary function of temporary casing during drilled-
pier construction?
a. Increase concrete strength
b. Prevent the excavation walls from collapsing
c. Replace reinforcing steel
d. Reduce the pier diameter
Answer: b. Prevent the excavation walls from collapsing
Rationale: Temporary casing supports unstable excavation walls and
can also help control groundwater and prevent loose material from
,entering the hole. It is removed as concrete is placed when the
construction method calls for casing extraction.
4. Before drilling begins, what should be verified regarding
underground utilities?
a. Only electrical utilities
b. Only water lines
c. The location of known and potentially affected underground utilities
d. Only utilities shown on the contractor's equipment drawings
Answer: c. The location of known and potentially affected
underground utilities
Rationale: Drilling equipment can encounter buried electrical, gas,
communications, sewer, and water facilities. Utility locating and
appropriate verification are essential before excavation begins to
prevent service damage, injury, and project delays.
5. What is a common method for keeping the walls of an unstable
drilled excavation open without permanent casing?
a. Dry sand placement
b. Stabilizing drilling slurry
c. Removing all reinforcement
d. Reducing the excavation depth
, Answer: b. Stabilizing drilling slurry
Rationale: Drilling slurry can exert hydrostatic pressure against the
excavation walls, helping prevent caving and reducing groundwater
intrusion. Proper slurry properties and maintenance are essential for
the method to work effectively.
6. In drilled-pier construction, what does the term "socket"
commonly refer to?
a. A threaded connection in reinforcing steel
b. A portion of the pier drilled into competent rock
c. The concrete placement tremie
d. The top of the reinforcing cage
Answer: b. A portion of the pier drilled into competent rock
Rationale: A rock socket is a drilled portion of a pier extending into
competent rock. It may be used to develop significant axial or lateral
resistance through sidewall bond, end bearing, or both, depending on
design.
7. Why is the bottom of a drilled excavation cleaned before concrete
placement?
a. To increase excavation diameter
b. To remove loose cuttings and debris that could compromise the
