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March 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 designs fail, the consequences can be terrible for the building owner and for the retailers in and around the building. Bad wind effects can (literally!) break businesses. Check out these two cases where a bad wind performance drastically impacted local businesses:

1. The Flatiron Building – New York City

The building resides at the end of an open corridor created by Madison Square Park. Its triangular form optimises 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 4 times larger than the average for the location. Although the structure was safe and sound, pedestrians and retailers suffered from the wind effects at ground level.

In 1903 shortly after it opened, one of the retailers in the area sued the building’s owners, claiming that the winds in its vicinity had shattered the plated 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 and into the path of a car.

The Flatiron Building location, in central New York

The Flatiron Building location in central New York City. 

2. The Hancock Tower - Boston

While it was still under construction, high winds were responsible for popping the windows out of the building – each glass window weighed 200 kilos! The opening had to be delayed from 1971 to 1976 and the reparation cost increased the building's overhead from 75 to $175 million.

Wind-load-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 reinforcements to prevent the walls and partitions from cracking in high winds.