NWSA Tower Structures and Inspection 2 — Questions and Answers
Question 1: What are the three main types of telecommunications tower structures?
- Wood, plastic, and concrete
- Self-supporting lattice, guyed, and monopole (Correct answer)
- Single-pole, double-pole, and triple-pole
- Residential, commercial, and industrial
Correct answer: Self-supporting lattice, guyed, and monopole
Self-supporting lattice towers use a wide base for stability, guyed towers use wire supports, and monopoles are single tubular structures.
Self-supporting lattice towers resist loads through their broad base without external support. Guyed towers are stabilized by guy wires and can reach over 2,000 feet. Monopoles are single tapered tubular structures preferred in urban areas for aesthetics.
Question 2: What structural deficiency would require immediate work stoppage during a tower climb inspection?
- Minor surface rust on a non-structural element
- Buckled or severely bent main structural members indicating potential structural compromise (Correct answer)
- A missing climb peg above 100 feet
- Faded paint on the tower identification sign
Correct answer: Buckled or severely bent main structural members indicating potential structural compromise
Buckled or bent main structural members indicate the tower may have been overloaded and could be at risk of structural failure.
Buckled or bent main structural members indicate loads exceeded member capacity. The damaged member has reduced capacity and may redistribute loads to other members. Work must stop immediately and a qualified structural engineer must assess the condition.
Question 3: How does ice loading affect tower structural integrity?
- Ice has no significant effect on towers
- Ice adds substantial weight to all structural members and equipment, increases wind loading due to larger cross-section, and can cause member failure (Correct answer)
- Ice only affects guy wires
- Ice damage only occurs in arctic regions
Correct answer: Ice adds substantial weight to all structural members and equipment, increases wind loading due to larger cross-section, and can cause member failure
Ice accumulation dramatically increases both dead weight and wind load on towers.
One inch of radial ice on all members can add tens of thousands of pounds. Ice increases wind profile dramatically. Uneven ice shedding causes violent oscillation. Guy wire ice changes tension and natural frequency. TIA-222-H specifies ice loading requirements by geographic location.
Question 4: What is the purpose of the TIA-222 standard in relation to telecommunications towers?
- It regulates cell phone pricing
- It establishes structural design, analysis, and inspection requirements for antenna supporting structures and antennas (Correct answer)
- It sets radio frequency power limits
- It determines tower paint colors
Correct answer: It establishes structural design, analysis, and inspection requirements for antenna supporting structures and antennas
TIA-222 is the primary industry standard governing structural design, loading criteria, and maintenance inspection requirements for telecommunications towers.
ANSI/TIA-222 covers structural design requirements, loading criteria for wind, ice, seismic, and equipment, foundation requirements, fabrication and installation standards, inspection and maintenance requirements, and modification analysis procedures.
Question 5: During a tower inspection, what should be checked at the foundation level?
- Only the paint condition
- Concrete condition, exposed rebar, soil erosion, grout pad integrity, anchor bolt condition, and drainage (Correct answer)
- Just the tower identification plate
- Foundation inspection is only needed during construction
Correct answer: Concrete condition, exposed rebar, soil erosion, grout pad integrity, anchor bolt condition, and drainage
The foundation is what holds the tower up. Deterioration at the foundation affects the entire structure's stability.
Foundation inspection checks concrete cracking and spalling, exposed reinforcing steel, anchor bolt condition and torque, grout pad integrity between base plate and pier, soil erosion undermining the foundation, drainage preventing freeze-thaw damage, and ground wire connections.
Question 6: What is the significance of guy wire tension readings during a guyed tower inspection?
- Guy wire tension doesn't affect tower performance
- Incorrect tension indicates the tower may be out of plumb, unevenly loaded, or have anchor problems that affect structural integrity (Correct answer)
- Tension readings are only needed during installation
- Only the top guy wires need tension checking
Correct answer: Incorrect tension indicates the tower may be out of plumb, unevenly loaded, or have anchor problems that affect structural integrity
Guy wires provide lateral stability. Incorrect tension can cause uneven loading, tower lean, and potential structural failure.
Under-tensioned guys provide insufficient support, allowing excessive deflection. Over-tensioned guys create excessive compression that can buckle members. Tension changes indicate slipping anchors, strand breakage, or hardware loosening. Readings should be compared to design specifications and tracked across inspection cycles.
NWSA Tower Structures and Inspection 2
What are the three main types of telecommunications tower structures?