CO Structural Steel Contractor Exam
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. Which of the following is the primary structural material used in steel
construction?
A. Aluminum
B. Steel
C. Wood
D. Concrete
Rationale: Steel is the primary material for structural steel
construction due to its high strength-to-weight ratio, ductility, and
durability.
2. What is the standard steel grade for structural members in the U.S.?
A. ASTM A36
B. ASTM A992
C. Both A and B
D. ASTM A500
Rationale: ASTM A36 and A992 are standard grades for structural
steel; A36 is widely used for general construction, while A992 is
common for wide-flange shapes.
3. The main advantage of using steel over concrete in structural framing
is:
A. Fire resistance
B. High strength-to-weight ratio
C. Low cost
D. None of the above
, Rationale: Steel provides high strength relative to its weight, allowing
longer spans and reduced material usage compared to concrete.
4. Which type of connection is commonly used for steel beams in
construction?
A. Mortar joint
B. Bolted or welded connection
C. Adhesive bond
D. Tongue-and-groove joint
Rationale: Steel beams are typically connected using bolting or
welding for structural integrity and load transfer.
5. What is the primary purpose of a steel column base plate?
A. Decorative
B. To transfer loads to the foundation
C. To resist corrosion
D. To facilitate welding
Rationale: Base plates distribute the column load to the foundation
and ensure proper alignment.
6. When welding structural steel, which gas is commonly used for
shielding?
A. Oxygen
B. Nitrogen
C. Argon or CO₂
D. Helium
Rationale: Shielding gases like Argon or CO₂ protect the weld pool
from atmospheric contamination.
7. Which of the following is a common type of structural steel section?
A. I-beam
B. Herringbone
C. Trapezoid
D. Circle
Rationale: I-beams (or wide-flange beams) are commonly used for
load-bearing structural members.
8. What is the function of bracing in a steel structure?
A. Aesthetic design
B. Provide lateral stability
C. Support roofing only
D. Increase thermal insulation
, Rationale: Bracing prevents lateral movement and maintains
structural stability under wind or seismic loads.
9. The term “dead load” refers to:
A. Live load on a structure
B. Permanent weight of structural elements
C. Temporary construction loads
D. Snow and wind loads
Rationale: Dead loads are the weight of structural components like
beams, columns, and floors.
10. The allowable stress in a steel member is determined by:
A. Yield strength only
B. Ultimate strength only
C. Factor of safety applied to yield strength
D. Elastic modulus
Rationale: Design codes limit allowable stress using the yield strength
divided by a factor of safety.
11. Which welding position is considered the most difficult for
structural steel?
A. Flat
B. Horizontal
C. Overhead
D. Vertical
Rationale: Overhead welding is challenging due to gravity affecting
the molten weld pool.
12. The purpose of galvanizing steel is to:
A. Strengthen it
B. Prevent corrosion
C. Make it magnetic
D. Improve weldability
Rationale: Galvanizing coats steel with zinc to protect against rust.
13. Which inspection method is non-destructive for checking steel
welds?
A. Cutting and testing
B. Ultrasonic testing
C. Tensile test
D. Hardness test
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. Which of the following is the primary structural material used in steel
construction?
A. Aluminum
B. Steel
C. Wood
D. Concrete
Rationale: Steel is the primary material for structural steel
construction due to its high strength-to-weight ratio, ductility, and
durability.
2. What is the standard steel grade for structural members in the U.S.?
A. ASTM A36
B. ASTM A992
C. Both A and B
D. ASTM A500
Rationale: ASTM A36 and A992 are standard grades for structural
steel; A36 is widely used for general construction, while A992 is
common for wide-flange shapes.
3. The main advantage of using steel over concrete in structural framing
is:
A. Fire resistance
B. High strength-to-weight ratio
C. Low cost
D. None of the above
, Rationale: Steel provides high strength relative to its weight, allowing
longer spans and reduced material usage compared to concrete.
4. Which type of connection is commonly used for steel beams in
construction?
A. Mortar joint
B. Bolted or welded connection
C. Adhesive bond
D. Tongue-and-groove joint
Rationale: Steel beams are typically connected using bolting or
welding for structural integrity and load transfer.
5. What is the primary purpose of a steel column base plate?
A. Decorative
B. To transfer loads to the foundation
C. To resist corrosion
D. To facilitate welding
Rationale: Base plates distribute the column load to the foundation
and ensure proper alignment.
6. When welding structural steel, which gas is commonly used for
shielding?
A. Oxygen
B. Nitrogen
C. Argon or CO₂
D. Helium
Rationale: Shielding gases like Argon or CO₂ protect the weld pool
from atmospheric contamination.
7. Which of the following is a common type of structural steel section?
A. I-beam
B. Herringbone
C. Trapezoid
D. Circle
Rationale: I-beams (or wide-flange beams) are commonly used for
load-bearing structural members.
8. What is the function of bracing in a steel structure?
A. Aesthetic design
B. Provide lateral stability
C. Support roofing only
D. Increase thermal insulation
, Rationale: Bracing prevents lateral movement and maintains
structural stability under wind or seismic loads.
9. The term “dead load” refers to:
A. Live load on a structure
B. Permanent weight of structural elements
C. Temporary construction loads
D. Snow and wind loads
Rationale: Dead loads are the weight of structural components like
beams, columns, and floors.
10. The allowable stress in a steel member is determined by:
A. Yield strength only
B. Ultimate strength only
C. Factor of safety applied to yield strength
D. Elastic modulus
Rationale: Design codes limit allowable stress using the yield strength
divided by a factor of safety.
11. Which welding position is considered the most difficult for
structural steel?
A. Flat
B. Horizontal
C. Overhead
D. Vertical
Rationale: Overhead welding is challenging due to gravity affecting
the molten weld pool.
12. The purpose of galvanizing steel is to:
A. Strengthen it
B. Prevent corrosion
C. Make it magnetic
D. Improve weldability
Rationale: Galvanizing coats steel with zinc to protect against rust.
13. Which inspection method is non-destructive for checking steel
welds?
A. Cutting and testing
B. Ultrasonic testing
C. Tensile test
D. Hardness test
