Free NWSA Tower Structures and Inspection Questions and Answers 1 — Questions and Answers
Question 1: According to the ANSI/TIA-222-H standard, what is the maximum recommended inspection interval for a guyed mast tower under normal environmental conditions?
- Every year
- Every 3 years (Correct answer)
- Every 5 years
- Every 10 years
Correct answer: Every 3 years
The ANSI/TIA-222-H standard specifies that guyed masts should be inspected at intervals of every three years, while self-supporting structures have a longer interval of five years under normal conditions.
Question 2: During an inspection of a monopole, a technician ensures the small opening at the base of each slip joint is clear of debris. What is the primary purpose of this component, known as a weep hole?
- To allow for the attachment of grounding conductors.
- To verify the proper overlap distance of the sections.
- To provide a lifting point for maintenance activities.
- To permit the drainage of internal condensation and moisture. (Correct answer)
Correct answer: To permit the drainage of internal condensation and moisture.
Weep holes are designed to allow any moisture that accumulates inside the hollow sections of a monopole to drain out. This prevents the buildup of water which can lead to internal corrosion and damage from freeze/thaw cycles.
Question 3: An inspector finds severe, localized corrosion where a stainless steel bracket is bolted directly to a galvanized steel tower leg. Which of the following best describes this type of corrosion?
- Pitting corrosion
- Crevice corrosion
- Galvanic corrosion (Correct answer)
- Uniform etch corrosion
Correct answer: Galvanic corrosion
Galvanic corrosion occurs when two dissimilar metals (like stainless steel and zinc-coated galvanized steel) are in electrical contact in the presence of an electrolyte (like moisture). The less noble metal (zinc) corrodes at an accelerated rate to protect the more noble metal (stainless steel).
Question 4: While performing a hands-on inspection of a guy wire, a technician discovers two broken wires within a single strand lay length. What is the generally accepted course of action according to industry standards?
- Note the finding for monitoring during the next inspection cycle.
- Clean and lubricate the area to prevent further breakage.
- Immediately report the condition for engineering review and likely replacement. (Correct answer)
- Apply a serving wire over the break as a temporary repair.
Correct answer: Immediately report the condition for engineering review and likely replacement.
Most standards and best practices for wire rope and guy strand inspection state that finding two or more broken wires in one lay length is cause for immediate removal from service or replacement. This condition significantly compromises the strength and safety of the guy wire.
Question 5: Which of the following findings during a visual inspection of a concrete tower foundation would require the most urgent attention and a formal structural engineering assessment?
- Minor surface efflorescence (white, powdery deposits).
- Small, non-moving hairline cracks on the surface.
- Exposed anchor bolt threads with no visible corrosion.
- A large, vertical crack that runs through a pier and shows signs of displacement. (Correct answer)
Correct answer: A large, vertical crack that runs through a pier and shows signs of displacement.
While minor cracks and cosmetic issues are common, a large structural crack with displacement (meaning the concrete on either side of the crack is no longer aligned) indicates significant movement and a potential failure of the foundation's integrity. This condition requires immediate engineering evaluation.
Question 6: On a lattice-type self-supporting tower, what is the primary function of the diagonal members that crisscross between the main tower legs?
- To serve as the primary climbing facility for technicians.
- To provide attachment points for antennas and transmission lines.
- To resist shear forces from wind and transfer loads between horizontal members. (Correct answer)
- To act as the main vertical load-bearing components of the structure.
Correct answer: To resist shear forces from wind and transfer loads between horizontal members.
In a truss structure like a lattice tower, the diagonal members are critical for providing rigidity and resisting shear (side-to-side) forces. They create triangular shapes, which are inherently stable, and transfer the wind and other lateral loads down the tower to the foundation.
Free NWSA Tower Structures and Inspection Questions and Answers 1
According to the ANSI/TIA-222-H standard, what is the maximum recommended inspection interval for a guyed mast tower under normal environmental conditions?