Flagpole – Wisconsin

Due to a lack of knowledge and experience concerning vibrations in high, slender structures, a previous attempt at building a high flagpole was unsuccessful. Up to 3 times a flagpole at this site has had to be dismantled. The first flagpole was too short (45m), after it was extended (60m) it collapsed due to high winds. The second flagpole (90m) had to be dismantled because it was not possible to service the aircraft warning lights. The third flagpole (100m) oscillated unacceptably with an amplitude up to 6 meters, see the wobbly flagpole movie below. It was dismantled for fear of collapse.

The final customer, a renowned insurance company, wanted to display its patriotism to the surrounding area and honour American Veterans with a large flag. That ambition was in serious danger after three failed attempts. Flow Engineering applied its advanced knowledge system (software and database) with respect to vortex-shedding to this problem for US Flag and Flagpole Supply, an international flagpole builder new to the project. Together with the flagpole builder the ambitions of the final customer were exceeded by 20% (+20m). The American flag was flying at a height of 120m after the rapid and flexible design, delivery, and installation of a Tuned Mass Damper system by Flow Engineering. Guaranteed to function for a period of 50 years through a thorough maintenance plan.

Together with Flow Engineering, US Flag and Flagpole Supply was able to realise the ambitions of the client.

“I truly feel that without the support of Flow Engineering the project would not have been as successful.”

Tom Jordan

Principle Owner, US Flag and Flagpole Supply

Project Details

  • Structure: Flagpole
  • Location: Sheboygan (WI), United States of America
  • Height: 120m
  • Weight: 180 000 kg
  • Diameter: 3.2m – 2m
  • Number of TMDs: 3
  • TMD 1
    • Mass: 2600 kg
    • Location: 109m
  • TMD 2
    • Mass: 2200 kg
    • Location: 116m
  • TMD 3
    • Mass: 3200 kg
    • Location: 91m

Previous design (100m) by an unrelated party:

Flow Engineering