The $20 million Spring Street Salt Shed, nearing completion on the Manhattan waterfront, has drawn curious stares from drivers along West Street and from pedestrians and bicyclists in Hudson River Park. Folded, creased, dimpled and chamfered, its windowless, enigmatic facade is like a monumental work of origami.

But once you know what it is — a concrete shed where 5,000 tons of de-icing salt for the roads of Lower Manhattan will be stored this winter — you’ll have a hard time getting the image of a giant salt grain out of your mind.

“In some ways, it’s the simplest building I’ve ever designed, and in some ways, it’s the most complicated,” said Richard Dattner, 78, who founded Dattner Architects 51 years ago. Among his firm’s latest projects is the extension of the No. 7 subway line to the 34th Street-Hudson Yards station.

...

The computer data was then used by the general contractor, Oliveira Contracting, to create the full-scale formwork into which the concrete was cast on site in 8-by-24-foot sections, between March and August. These molds were made of polystyrene up to six feet thick.

The formwork was then stripped away, revealing a lustrous concrete surface that was glacially blue. That color comes from slag in the mix, said Gia L. Mainiero, an associate of Mr. Dattner, and will fade over time as the concrete grows whiter.