Case Study: Fiberglass Light Pole Performance in Hurricanes

Lessons for High-Wind Regions

In recent hurricane seasons, several Florida communities have reported damage to fiberglass light poles following major storm events. While fiberglass poles are designed and rated for high wind speeds — often up to 150 mph — field performance can vary depending on soil conditions, installation methods, and the cumulative effects of repeated storms.

This article highlights common patterns observed in the field and explains why poles that “pass” on paper may still experience leaning, attachment failures, or fractures under real storm conditions.

What Was Observed

• Leaning poles: Many poles developed measurable tilt (3–5%, with some exceeding that threshold).

• Fractures: A small percentage broke at the groundline, mid-height, or near attachments.

• Attachment failures: Fixtures and solar assemblies were often the first components to fail.

• Soil disturbance: Utility trenching and variable compaction reduced confinement in some cases.

Wind Ratings vs. Real-World Performance

Static Analysis (Design Basis):

• Manufacturer ratings are based on static wind load checks and assume the pole is installed plumb, with full embedment, and well-compacted soils. These ratings also use the published EPA (Effective Projected Area) values for fixtures and attachments. (See EPA rating calculator.)

• However, it’s important to note that dynamic storm effects — such as pole rocking, gust cycles, and vibration — are not captured in the static EPA rating. Even if a pole “passes” its rated EPA value on paper, real-world performance can differ if installation or soil conditions are less than ideal.

Takeaway: By the book, these type of poles should perform — but only if all design assumptions (embedment depth, soil confinement, and installation quality) are achieved in practice. Dynamic behavior under real hurricane conditions can still drive failures if those assumptions aren’t met.

Why Some Poles Still Failed

Static ratings don’t capture dynamic storm behavior:

1. Loose soil at the upper embedment

   • If the top 12–24 in of soil isn’t compacted in proper lifts, even small voids allow rocking.

   • Small base movements are magnified into large motions at the pole top.

2. Fiberglass flexibility

   • Fiberglass is lighter and more flexible than aluminum or steel.

   • While beneficial in many ways, this flexibility makes poles more sensitive to loose embedment.

3. Cumulative storm effects

   • When storms occur close together, saturated soils and repeated gust cycles create stresses beyond a single static wind check.

4. Amplified loads on attachments

   • Base rocking + shaft flexibility = higher stresses at fixtures and solar assemblies.

   • Many attachment failures are linked to this amplified motion rather than pole weakness.

Lessons for Future Projects

• Pole embedment is Key
  Typically, 20-25% of the Pole Length is recommended to be inside properly compacted ground (or as per the foundation engineering or geotechnical report).

• Prioritize soil compaction
  Direct-bury installations require lift compaction (6–12 in) or engineered collars to avoid long-term tilt.

• Account for dynamics, not just statics
  Current industry practice for pole wind ratings relies on static methods such as ASCE 7 wind load provisions and manufacturer EPA (Effective Projected Area) ratings. These approaches are the accepted design basis and are considered compliant with the standard of care for structural engineering.

  That said, static ratings do not capture dynamic effects such as soil–structure interaction, cyclic gust loading, or cumulative storm sequences. In hurricane-prone regions, these factors can influence long-term performance, particularly for flexible materials like fiberglass. While the static checks confirm the poles meet code intent, it may be prudent for future designs and procurement to also consider embedment quality, compaction verification, and potential dynamic response to reduce the risk of tilt and attachment failures under real storm conditions.

• Review attachment details
  Fixtures and solar assemblies often fail before poles. Attachment design and fatigue resistance should be part of the overall system review.

Closing Note

Fiberglass poles remain a strong, lightweight, and corrosion-resistant option for many communities. But as these events show, real-world performance depends on more than design wind ratings. Proper embedment, soil confinement, and attention to dynamic effects are critical for long-term reliability in high-wind regions.

Disclaimer: This article is provided for educational purposes only. It does not reference or evaluate any specific project, client, or installation. Observations are generalized from industry experience in hurricane-prone areas.