Metro plans a unique canopy for Dupont's north entrance
Metro plans on covering Dupont Circle's large, circular Q Street station entrance with a tweaked version of its iconic canopy.
The elliptical shelter will be the first unique design since Metro began regularly adding canopies to protect escalators. While most outdoor Metro escalators go underground in tight rectangular shafts, at Q Street the escalators pass through a huge drum-shaped pit.
Because the pit is such an unusual shape, Metro needs a different canopy design.
If all continues to go as planned, WMATA expects to complete construction in 2018.
History of the canopy program
The engineers of the original Metro system didn't think it would be cost-effective to cover all the system's many escalators. But by 1999 increasing escalator breakdowns and a change to DC's building code required WMATA to build canopies over its entrances.
After a bad reaction to early canopies at Petworth and Glenmont, Metro held a design competition. They ultimately chose a simple glass design by Lourie & Chenoweth Architects because it evokes stations' coffered ceilings and can be easily adapted to multiple sites.
After finalizing the designs, Metro installed the first of its standardized canopies in 2003 at Virginia Square, Brookland, L'Enfant Plaza, and Medical Center.
The standard canopy design
Imagine a doughnut that's standing upright, 600 feet in diameter, buried in the ground. The architects took a rectangular patch of that doughnut's surface as the overall shape for the new canopy.
This meant a double-curved surface could be made out of flat pieces of glass and simple pieces of stainless steel.
If this idea sounds familiar, it was used to build the Sydney Opera House and the glass wall at Arena Stage.
Other glass roofs curved in two directions require expensive triangular construction, fragile cold-bent glass, or glass that pops out slightly. The latter is how architects designed the ceiling at the Kogod Courtyard.
The glass roof of the Smithsonian's Kogod Courtyard. Image by Foster + Partners / Buro Happold.
Because of the doughnut-like "toric" shape, the Metro canopy's glass only needs to be cut into trapezoids, and the steel girders need curves in only one direction. Most of the units repeat, simplifying manufacturing. Depending on how wide or long the escalator shaft is, Metro can stretch the geometry to fit. The architects got a lot of visual play for Metro's dollar.
The Dupont canopy
For the Q Street canopy, Metro brought back Lourie & Chenoweth. Their design relies on a geometric trick that keeps the structure light and window system simple, while allowing for a large enough canopy to cover the escalator pit.
To adapt the system to the circular opening, Lourie & Chenoweth simply cut an elliptical section from the torus, instead of the regular rectangular one. This means the entire rim will require curved cuts. The steel girder will take the form of a bent circle, directly above the lip of the drum.
The design is meant to keep the plantings down below alive, in addition to all the usual requirements of canopies.
Growing up, I thought the Q Street entrance was an incredibly cool way to see the sky. But as an adult, my enthusiasm is tempered by all the umbrellas I've lost to the winds this pit creates. Hopefully, this design will retain some of what makes the entrance unique, while more effectively keeping riders and escalators out of the rain.
What do you think, is it a great twist on an existing idea, or should they have gone for something totally new?
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