The A-Corda Bridge responds to the competition brief by proposing a link for pedestrians and cyclists in neighborhoods on either side of a busy suburban Lisbon expressway. Galp - Portugal's largest oil and gas company - sponsored the competition and encouraged thinking about carbon footprint and the generation of on-site energy. In response to the competition's motto, "It's About Time," A-Corda is also a wake-up call for drivers to reconsider their commute by bike or by foot.
Recalling the experience of walking through the streets of Alfama, the turns of the bridge form a curved walking path though oak trees and a terraced landscape. The span across the 2a circular is not only a means of crossing the road, but also serves as an experiential and visual connector to the sinuous character of the nearby trails of Monsanto Park.
Lisbon has never been a city that conforms to a grid, and the network of future cycling lanes and pedestrian friendly routes will have to incorporate a varied terrain rather than fight against it. The notion of a switchback trail is incorporated into the design of the bridge in order to manage speeds and allow for cyclists and pedestrians to share the same path.
Structurally, the bridge is supported from below by a chord of tension cables. The taut strings are lifted by a series of fret-like frames and a truss box that also serve to transfer loads from the bridge to the tension cable system. Evoking the strings of a guitar, the A-Corda’s structure is in tune with the history of structural innovation and experimentation in Portugal.
As the path winds its way through the natural landscape and a solar field of photovoltaic “trees” the cyclist and the pedestrian will experience the bridge as a strip of park-land floating over the fast-paced highway below. The solar panels produce energy to power the imbedded LED lighting pattern, illuminating the bridge for use after dark. The PV trees are a symbol of the bridge’s closed sustainable system and of Galp Energia’s commitment to the future of alternative energy in Portugal.