ICC Structural Steel and Bolting Special
Inspector Examination (S1) Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
Question 1
A high-strength bolt installed in a slip-critical connection primarily relies on which
mechanism for load transfer?
A. Bearing of the bolt shank against the hole walls
B. Friction between the connected steel plies
C. Shear strength of the bolt threads
D. Tensile capacity of the bolt head
Answer: B. Friction between the connected steel plies
Rationale: In a slip-critical connection, the primary mechanism for transferring
load is the friction developed between the faying surfaces of the connected
elements. This friction is generated by the clamping force from the pretensioned
high-strength bolts. Bearing of the bolt against the hole is the mechanism for
bearing-type connections, not slip-critical joints .**
Question 2
What is the primary purpose of pre-tensioning high-strength bolts in structural
steel connections?
A. To reduce the bolt diameter for easier installation
B. To prevent corrosion of the bolt and nut assembly
C. To increase the frictional resistance between the connected plies
D. To allow the bolt to yield before the connected steel members
,Answer: C. To increase the frictional resistance between the connected plies
Rationale: The primary purpose of pre-tensioning is to create a clamping force
that brings the connected plies into firm contact. This clamping force increases the
friction between the plies, which is essential for the performance of slip-critical
connections. It also improves the fatigue performance of all connection types .**
Question 3
In structural steel inspection, what is the acceptable method for verifying bolt
pretension using the turn-of-nut method?
A. Measuring the temperature of the bolt during tightening
B. Counting the rotation of the nut from the snug-tight condition
C. Checking the size of the weld bead adjacent to the bolt
D. Measuring the elongation of the bolt with a micrometer
Answer: B. Counting the rotation of the nut from the snug-tight condition
Rationale: The turn-of-nut method is a recognized and acceptable way to verify
pretension. The procedure involves first bringing the joint to a snug-tight
condition. The nut is then rotated a specified amount (e.g., 1/2 or 1/3 turn) to
develop the required tension, directly correlating nut rotation to bolt
elongation .**
Question 4
What is the primary function of ASTM A325 and A490 bolts?
A. Decorative fastening for architectural elements
B. High-strength structural connections in steel framing
C. Temporary scaffolding and falsework connections
D. Electrical grounding for structural steel
Answer: B. High-strength structural connections in steel framing
Rationale: ASTM A325 and A490 are specifications for high-strength structural
bolts used in steel building and bridge construction. They are designed for
connections that require high strength and reliability, unlike standard bolts which
are not suitable for primary structural applications .**
,Question 5
A bolted joint classified as a “bearing-type” connection primarily transfers load
through:
A. Friction between the connected plates only
B. Shear strength of the weld material
C. Bearing of the bolt shank against the walls of the hole
D. Adhesive bonding of the connected surfaces
Answer: C. Bearing of the bolt shank against the walls of the hole
Rationale: In bearing-type connections, the design assumes that slip may occur
between the connected plies. The load is transferred when the bolt shank comes
into contact with the side of the bolt hole, distributing the force through bearing
on the connected material. This is distinct from slip-critical connections where slip
is not permitted .**
Question 6
What does ASTM F3125 specify?
A. Standards for structural welding procedures
B. A unified specification for high-strength structural bolts
C. Requirements for structural steel shapes
D. Standards for concrete reinforcement
Answer: B. A unified specification for high-strength structural bolts
Rationale: ASTM F3125 is a relatively new specification that consolidates and
replaces several previous individual standards for high-strength structural bolts,
including A325 and A490. This unification simplifies the process of specifying and
procuring high-strength bolts for structural applications .**
Question 7
Which of the following conditions most directly affects the torque-tension
relationship during bolt installation?
A. The color of the bolt head coating
B. The surface condition and lubrication of the bolt threads and nut bearing
, surfaces
C. The overall height of the steel building frame
D. The tensile strength of the connected steel plates
Answer: B. The surface condition and lubrication of the bolt threads and nut
bearing surfaces
Rationale: The torque-tension relationship is highly dependent on friction.
Variations in lubrication, surface finish, and contaminants can significantly change
the amount of torque required to achieve a given bolt tension. This is why the
calibrated wrench method requires careful control and frequent calibration .**
Question 8
What is a primary reason for using a galvanized coating on a high-strength bolt?
A. To increase the bolt's tensile strength
B. To provide corrosion resistance
C. To make the bolt easier to thread
D. To improve the aesthetics of the connection
Answer: B. To provide corrosion resistance
Rationale: Galvanizing provides a layer of zinc that protects the steel bolt from
corrosion. However, it is important to note that the galvanized coating changes
the friction characteristics of the bolt, which can affect torque-based installation
methods and may require special considerations .**
Question 9
A “snug-tight” condition for a bolted joint is best described as:
A. A bolt that has been fully tensioned to its specified pretension
B. A bolt that has been tightened with an impact wrench until it yields
C. The condition in which the connected plies have been brought into firm contact
and the bolt is snugged by the full effort of an ironworker using an ordinary spud
wrench or impact wrench
D. A loosely installed bolt that has not yet been torqued
Inspector Examination (S1) Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
Question 1
A high-strength bolt installed in a slip-critical connection primarily relies on which
mechanism for load transfer?
A. Bearing of the bolt shank against the hole walls
B. Friction between the connected steel plies
C. Shear strength of the bolt threads
D. Tensile capacity of the bolt head
Answer: B. Friction between the connected steel plies
Rationale: In a slip-critical connection, the primary mechanism for transferring
load is the friction developed between the faying surfaces of the connected
elements. This friction is generated by the clamping force from the pretensioned
high-strength bolts. Bearing of the bolt against the hole is the mechanism for
bearing-type connections, not slip-critical joints .**
Question 2
What is the primary purpose of pre-tensioning high-strength bolts in structural
steel connections?
A. To reduce the bolt diameter for easier installation
B. To prevent corrosion of the bolt and nut assembly
C. To increase the frictional resistance between the connected plies
D. To allow the bolt to yield before the connected steel members
,Answer: C. To increase the frictional resistance between the connected plies
Rationale: The primary purpose of pre-tensioning is to create a clamping force
that brings the connected plies into firm contact. This clamping force increases the
friction between the plies, which is essential for the performance of slip-critical
connections. It also improves the fatigue performance of all connection types .**
Question 3
In structural steel inspection, what is the acceptable method for verifying bolt
pretension using the turn-of-nut method?
A. Measuring the temperature of the bolt during tightening
B. Counting the rotation of the nut from the snug-tight condition
C. Checking the size of the weld bead adjacent to the bolt
D. Measuring the elongation of the bolt with a micrometer
Answer: B. Counting the rotation of the nut from the snug-tight condition
Rationale: The turn-of-nut method is a recognized and acceptable way to verify
pretension. The procedure involves first bringing the joint to a snug-tight
condition. The nut is then rotated a specified amount (e.g., 1/2 or 1/3 turn) to
develop the required tension, directly correlating nut rotation to bolt
elongation .**
Question 4
What is the primary function of ASTM A325 and A490 bolts?
A. Decorative fastening for architectural elements
B. High-strength structural connections in steel framing
C. Temporary scaffolding and falsework connections
D. Electrical grounding for structural steel
Answer: B. High-strength structural connections in steel framing
Rationale: ASTM A325 and A490 are specifications for high-strength structural
bolts used in steel building and bridge construction. They are designed for
connections that require high strength and reliability, unlike standard bolts which
are not suitable for primary structural applications .**
,Question 5
A bolted joint classified as a “bearing-type” connection primarily transfers load
through:
A. Friction between the connected plates only
B. Shear strength of the weld material
C. Bearing of the bolt shank against the walls of the hole
D. Adhesive bonding of the connected surfaces
Answer: C. Bearing of the bolt shank against the walls of the hole
Rationale: In bearing-type connections, the design assumes that slip may occur
between the connected plies. The load is transferred when the bolt shank comes
into contact with the side of the bolt hole, distributing the force through bearing
on the connected material. This is distinct from slip-critical connections where slip
is not permitted .**
Question 6
What does ASTM F3125 specify?
A. Standards for structural welding procedures
B. A unified specification for high-strength structural bolts
C. Requirements for structural steel shapes
D. Standards for concrete reinforcement
Answer: B. A unified specification for high-strength structural bolts
Rationale: ASTM F3125 is a relatively new specification that consolidates and
replaces several previous individual standards for high-strength structural bolts,
including A325 and A490. This unification simplifies the process of specifying and
procuring high-strength bolts for structural applications .**
Question 7
Which of the following conditions most directly affects the torque-tension
relationship during bolt installation?
A. The color of the bolt head coating
B. The surface condition and lubrication of the bolt threads and nut bearing
, surfaces
C. The overall height of the steel building frame
D. The tensile strength of the connected steel plates
Answer: B. The surface condition and lubrication of the bolt threads and nut
bearing surfaces
Rationale: The torque-tension relationship is highly dependent on friction.
Variations in lubrication, surface finish, and contaminants can significantly change
the amount of torque required to achieve a given bolt tension. This is why the
calibrated wrench method requires careful control and frequent calibration .**
Question 8
What is a primary reason for using a galvanized coating on a high-strength bolt?
A. To increase the bolt's tensile strength
B. To provide corrosion resistance
C. To make the bolt easier to thread
D. To improve the aesthetics of the connection
Answer: B. To provide corrosion resistance
Rationale: Galvanizing provides a layer of zinc that protects the steel bolt from
corrosion. However, it is important to note that the galvanized coating changes
the friction characteristics of the bolt, which can affect torque-based installation
methods and may require special considerations .**
Question 9
A “snug-tight” condition for a bolted joint is best described as:
A. A bolt that has been fully tensioned to its specified pretension
B. A bolt that has been tightened with an impact wrench until it yields
C. The condition in which the connected plies have been brought into firm contact
and the bolt is snugged by the full effort of an ironworker using an ordinary spud
wrench or impact wrench
D. A loosely installed bolt that has not yet been torqued
