Admittedly, this recently completed footbridge isn't the easiest, nor the most practical way to get people from one side of a river to another – but it might be one of the most creative. The unique crossing can roll a full 180 degrees to make space for boats to pass under it.
Appropriately named the Cody Dock Rolling Bridge, the project was realized as part of a larger redevelopment of a former industrial dock area in London, England. The dock is now home to an artistic community who are in the process of transforming it into a creative hub.
As part of the renovation, it was decided to reopen the dock to a nearby river's tidal waters, which in turn required the removal of an old dam on the site and the construction of a new footbridge. Simon Myers, of Gasworks Dock Partnership, who's in charge of redeveloping the dock, was intending to install a traditional bascule bridge for the site. However, when architect Thomas Randall-Page heard of these plans, he approached Myers and, with the support of engineer Tim Lucas, pitched a counter proposal for a far more ambitious rolling bridge.
The resulting bridge is partly inspired by Victorian-era infrastructure like canal locks and is constructed from weathered steel and oak, weighing in at 13 tonnes (almost 15 US tons). It works like this. In its usual position, cyclists and pedestrians simply make their way across like a normal bridge. However, when a boat needs to pass under it, steel teeth installed on the ends of the bridge allow it roll on a pair of tracks that are installed into the concrete abutments on either bank, significantly increasing headroom for the boats. The process takes about 20 minutes, so it's not like it turns too suddenly to be safe, despite how fast it looks in the timelapse above.
The bridge includes scrap metal and concrete ballast, countering the weight of the deck and enabling it to smoothly roll through an entire 180 degrees until it comes to a stop at a fully inverted position. Impressively, the whole thing is so carefully engineered that it requires no motors or electricity to move. Instead, it's totally powered by hand winches.
"Raising, swinging, sliding, folding and tilting ... the solutions to the challenge of the opening bridge are many and varied," said Randall-Page's press release. "Seeing the potential for public spectacle inherent in the opening of a bridge, Thomas set about adding to this long established list of motions. Rolling along to the channel it crosses, this unique bridge design owes much to its Victorian forbears.
"They knew that moving large heavy structures efficiently requires that they are part of balanced systems, and this design works on the same principle of equilibrium. Part of an ambitious community led regeneration project, we hope this revolutionary bridge will become an important landmark and a symbol of the dynamic creative community which is growing here."
Source: Thomas Randall-Page
