Transportation designers Rosales and Partners have been selected through an invited competition organized by the Anacostia Waterfront Corp. to construct a bridge in Washington, D.C. The winning design, a curved tube structure composed of steel cables, concrete decks, painted steel and possibly a stainless steel roof, will join the Minnesota Ave. Metro Station to the proposed Kenilworth/Parkside development project over a major rail network and highway.
“The bridge is made of standard elements, but the way they are put together makes it different,” says Designer Miguel Rosales. The bridge will be built in stages. The piers of the bridge, its footings, will be built in place, but the three main pieces of the walkway will be brought in once they are built off site. Literally overnight, the pieces will then be placed on the piers and joined. “It can be built in pieces,” says Rosales. “You don’t have to interrupt the traffic with major disruptions, and I think that’s critical.”
The bridge is designed for add-ons, including safety nets and surrounding cages, but it will not be enclosed. “There will be a roof, but it will be open,” says Rosales. “We might be able to put some heating wires in the concrete surface where people walk, so you can control the rain and the snow, but I wasn’t thinking to enclose it because then you have to put in air conditioning and all sorts of different mechanical equipment.”
By not being enclosed, the design also takes safety into account. Rosales says, “You can see all the points of entry, especially at night when you are crossing from one side to the other.”
Rosales says the curved construction of the bridge adds to its stability. “When you do a curve, it starts to be really more rigid than if you do a straight line,” he says. “If I were making a straight bridge, with more or less a similar system, all of the elements would need to be thicker because you don’t have that intrinsic rigidity of the curve.”
According to Rosales, the design and function of the bridge went hand-in-hand. “Bridges, they need to have a function and that needs to be fulfilled first, and then they can also have a visual and aesthetic appeal, but the two things have to work together. There has to be a reason behind it. There has to be an engineering reason why you are doing a bridge.”