Building bridges over busy waterways tends to be accompanied by delays and disruptions to shipping traffic. Installing the steel structure, building the wooden formwork for casting the concrete deck, erecting the falseworks to support the formwork, dismantling the falsework and formwork after the concrete has hardened - all of these activities will unavoidably inconvenience or even block the normal passage of ships and barges on the canal or river.
The engineers building the Uyllander bridge in Amsterdam, which spans the busy Amsterdam-Rhine Canal, an important shipping artery connecting the port of Amsterdam to the Rhine River, therefore decided to try something new.
Rather than moving the steel structure into place and then building the formwork, they turned the process around. The structure - a steel arch and steel trusses spaced 3.8 meters apart - was constructed on shore, after which a lightweight, polymer sandwich-panel formwork was installed, also on shore.