Synopsis
The brief for the Lucie-Bréard footbridge in Paris was to replace two existing inaccessible bridges across a canal with one, new, combined, accessible, pedestrian and cycle bridge. A typical project approach would demolish the existing bridges and replace them with new construction material – a linear economy in construction. Instead, the deck of one of the existing bridges was deconstructed, reconditioned and adapted to form the main span of the new bridge, applying structural principles of a circular economy in construction.
This article introduces the favourable project context and the existing site conditions. It presents concepts of a circular economy before exploring three key considerations for the structural reuse of existing bridge elements in the Lucie-Bréard footbridge: evaluating existing material properties, changing the boundary conditions and structural mechanics, and appropriate construction methods. It concludes by estimating and evaluating the embodied carbon impacts of a circular economy compared with a typical linear economy approach.