When Hurricane Ian swept across Florida in 2022, several aluminum light poles on a bridge in Central Florida suddenly cracked or collapsed.
What puzzled engineers was that the wind speeds during the storm were actually below the levels the poles were designed to withstand.
A new study from the University of Florida reveals that the failures were not caused by the hurricane alone, but by a combination of hidden problems that weakened the structures.
The research team from the university’s Herbert Wertheim College of Engineering discovered that the poles had multiple small weaknesses that, when combined, dramatically reduced their safety.
The poles met official design standards and had been recently installed, so they were expected to perform well. However, the study found that manufacturing defects, design details that concentrated stress, and installation mistakes all played a role in the unexpected collapse.
Working with the Florida Department of Transportation, the researchers carefully examined the damaged poles. They looked inside the metal, tested its strength, reviewed how the poles had been installed, and used computer simulations and wind tunnel experiments to recreate hurricane conditions.
This detailed investigation revealed that the aluminum bases contained tiny air pockets formed during manufacturing. In some cases, these hidden gaps made up more than eight percent of the material, far above what industry guidelines allow. As a result, the metal was up to 25 percent weaker than it should have been.
Installation problems made the situation worse. Field inspections found uneven nuts, mismatched washers, and bolts that were not perfectly aligned.
Computer models showed that even small installation errors — such as a nut tightened slightly too much or too little — could increase stress on the weakened metal. When strong winds pushed against the poles, these extra stresses were enough to cause the material to crack.
The way the wind moved around the bridge also contributed to the failures. Analysis showed that air flow amplified pressure at specific points near the anchor bolts, especially on the side facing the strongest winds during the storm.
Cracks began at these points and spread rapidly, causing sudden breakage rather than gradual weakening over time.
Researchers say the findings highlight an important lesson: meeting design standards alone does not guarantee safety in real-world conditions. Engineering codes include safety margins to account for normal variations, but those margins can be overwhelmed if several small problems occur at the same time. In this case, defects in the material and installation pushed the poles beyond what the design could handle.
The study suggests that improving quality control during manufacturing, ensuring careful installation, and making small design adjustments could help prevent similar failures in the future. For hurricane-prone regions, these steps could strengthen infrastructure and improve public safety.
By examining design, production, and installation together rather than separately, engineers can better understand how structures behave during extreme events. The research shows that infrastructure resilience depends not just on strong designs, but on every stage of the process working correctly — from factory to construction site to the forces of nature.
