MAR 2019, Luma Bendini

Two buildings that failed wind performance badly

The aerodynamics of a high-rise building is a tricky thing! Tall structures act like funnels, pushing wind downwards creating an uncomfortable and potentially dangerous area for pedestrians. When building design fails the consequences can be terrible for the building owner and for the retailers in or close to the building. Bad wind effect can (literally!) break businesses. Check out these two cases were a bad wind performance affected local business:

1. Flatiron Building – New York City

The building resides at the end of an open corridor created by Madison Square Park and its triangular form optimizes flow separation and acceleration towards the surrounding streets. As the wind gusts reach the curved front edge of the building, they create accelerated wind flow in the lateral streets.

The wind was such an important factor when the building was built that engineers designed it to resist wind loads 4x larger than the average for the location. Although the structure was safe and sound, pedestrian and retailers suffered from the wind effects in ground level.

In 1903, shortly after it opened, one of the retailers in the area sued building’s owners saying that the winds in its vicinity had shattered the plate-glass windows of his store across the street twice in just two weeks. Also, a messenger boy died due to a strong wind coming off the building and knocking him from the sidewalk into the path of a car.

The Flatiron Building location, in central New York

2. Hancock Tower - Boston

While it was still under construction, high winds were responsible for popping the windows out of the building – each glass window weighted 200 kilos! Because of that, the opening had to be delayed from 1971 to 1976 and the cost went from $75 million to $175 million.

The window design was not compatible with the wind loads that such a high building was being exposed too.

Wind-loads-related problems didn’t stop there. After construction was completed, it was also discovered that the tower swayed to a dangerous degree. Engineers had to install interior reinforcement to prevent walls and partitions from cracking in high winds.