As part of the refurbishment of the ancient Petersberg Citadel in Erfurt for the Bundesgartenschau 2021 (National Horticultural Show), a competition for a barrier-free access to the fortress was launched in 2016. The winning Design Team proposed a free-standing 14m high lift-tower in steel with two connecting lightweight steel bridges to the fortress.
The classification of Petersberg Fortress as a cultural monument and the resulting requirements and restrictions from the preservation order posed a particular challenge in designing the support point for the footbridge on the fortress wall. The structure of the lift-tower consists of two truss girders and two Vierendeel girders. The tower is cantilevering from the ground in order to minimize horizontal loads onto the fortress. For the same reason the walkways were designed to be slender and filigree, bringing just a relative small additional vertical load to the centuries-old stonework.
La Troche FootbridgeSaclay, France
Skylink Squaire MetroFrankfurt, Germany
Tondo footbridgeBrussels, Belgium