Well I'm not sure that it's a concept the designers aimed for, rather I believe something they had to incorporate into the design due to it's previous existence as the route to the bird exhibits.
Is there a wire fence on both sides of the bridge to prevent objects being dropped into the elephant exhibit? I can recall seeing construction on this development in 2008 on my solitary visit to the National Zoo, and so it is exciting to finally view photos here on ZooChat.