Giant umbrellas shift from convenient canopy to sturdy storm shield

Wednesday, Apr 1, 2020
by Molly Sharlach

In a new approach to storm surge protection, a Princeton team has created a preliminary design for these dual-purpose kinetic umbrellas. In a study published Mar. 28 in the Journal of Structural Engineering, the researchers used computational modeling to begin evaluating the umbrellas’ ability to withstand an acute storm surge.

As sea levels rise and storms grow stronger, coastal communities are building more seawalls to help protect people and property from extreme flooding. These barriers can be unattractive and restrict access to beaches, but the Princeton team’s umbrellas would provide shade during fair weather and could be tilted in advance of a storm to form a flood barrier.

“This is so much more than just your typical coastal defensive structure,” said lead study author Shengzhe Wang, a Ph.D. student in civil and environmental engineering. “It’s the first time that anyone has really tried to integrate architecture as an inherent component to a coastal countermeasure.”

The proposed umbrellas are shells of reinforced concrete about 4 inches thick, built in the shape of a hyperbolic paraboloid (shortened to hypar), a saddle-like structure that curves inward along one axis and outward along the other. The structure takes inspiration from the work of the Spanish-born architect Félix Candela, who designed hundreds of buildings with thin-shelled hypar roofs in Mexico in the 1950s and 1960s.

Study co-author Maria Garlock, a professor of civil and environmental engineering, has long studied Candela’s designs; she co-wrote a book on Candela and helped create an archive and exhibition exploring his work. In the fall of 2017, she and co-author Branko Glišić, an associate professor of civil and environmental engineering, were considering a project to study the potential of hypar umbrellas as “smart” structures to capture energy and rainwater. Then, a new idea came to her: In addition to adding sensors, “why not tip them and use them in a completely different way —as a kind of seawall?” she asked.

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