Note: An abridged version of the following post was also published online at the Star Tribune's Your Voices forum. Your comments are welcome in each forum.
The realities of climate change, rising gas prices and budget constraints compel us to use our developed area more intentionally and productively. Our assets will need to produce multiple benefits – parking lots become stormwater collection systems, roofs become collectors of energy, and road rights of way become tillable land area. All around us is space that we’ve underused over time.
Bridges are a good example. Inhabited bridges, or bridges that support a superstructure of residential and commercial buildings, are being reconsidered as an innovative way to add capacity, jobs, tax base, green space and character to urban centers. As in many cities located on major waterways, bridges can serve as iconic landmarks that structure the urban landscape and hold powerful symbolic connotations of community integration. And beyond symbolism, inhabited bridges capture space from the air, to house jobs or shared spaces.
Certainly not a 21st century innovation, bridges that contain residential and commercial uses have been an historic solution to limited available land for development in medieval European cities. From the 12th to the 18th centuries, at the apex of their popularity, mixed-use bridges were built throughout Europe. In economic terms, their construction shows that the value of proximity outweighed building and maintenance cost. Notable and popular examples include Old London Bridge, Ponte Vecchio, and Ponte di Rialto (here are the shops). The Old London Bridge was built in 1209 and housed nearly 200 shops as well as numerous residences that provided the revenue for the bridge’s construction and maintenance.
Still standing in Italy, the Ponte Vecchio of Florence and the Ponte di Rialto of Venice (built respectively in 1345 and 1591) continue to be iconic structures and popular tourist attractions lined with flourishing shops. With little land available for expansion, medieval cities built inhabited bridges to maximize available space while minimizing government expenditure on maintenance through the taxation of residential and commercial entities inhabiting the bridge. The popularity of inhabited bridges, however, all but vanished following the 18th century as the demands of traffic and outward movement escalated, and the value of proximity fell in relation to construction and maintenance costs.
Nonetheless, the inhabited bridge may not be a mere relic of the past but innovative solution to modern urban problems. The surviving Italian inhabited bridges testify to their modern applicability and the lasting import of their unique construction.
Following their heyday, numerous plans for inhabited bridges have both been proposed and denied due to their perceived impracticality in a world dependent on motor vehicles. However, at the turn of the 21st century, the idea of inhabited bridges has gained greater attention. Construction of inhabited bridges appears to offer significant benefits and opportunities for the modern city. The “Living Bridges: The Inhabited Bridge: Past, Present & Future” exhibit at the Royal Academy of Arts in London in 1996 brought the concept of inhabited bridges to global attention and was met both with enthusiasm skepticism. A large component of the exhibit was an architectural competition to design an inhabited bridge.
Again, in 2009, a similar competition was undertaken to commemorate the 800th anniversary of the construction of the Old London Bridge. While much of this interest has not begotten bridge construction, the inhabited Zaragoza Bridge crossing the Ebro River in Spain was constructed in 2008 to combine a pedestrian walkway with exhibition spaces focusing on water sustainability. Although new construction, the Zaragoza Bridge is an initial effort at redeploying the inhabited bridge for modern development.
As global and economic factors converge to redirect our attention inwards, we are faced with cities that are compartmentalized by networks of major roadways. Communities and businesses within our cities are separated by natural barriers like rivers as well as man-made ones. Symbolically and physically, these communities are in need of being bridged. The inhabited bridge may serve to restore a disjointed urban social fabric, and release space for the creation of jobs, tax base, green space or others uses in places across the country.
Photo: Ponte Vecchio detail. Courtesy of Flickr/CGoulao