FOOTBRIDGE “UMBRIA GATEWAY”
FOOTBRIDGE “UMBRIA GATEWAY” (Terni, Italy)
Year: 2013 – 2015
In 2012 an International Competition opened for a project of a footbridge facilitating the overpass of the nearby station rail tracks. The winner project was that of Benedetti Architects: 180 meters of span, divided into a curved cable-stayed bridge (roughly 140 meters) and a straight arch bridge, for connecting the city centre with the other side of the railway. The tower of the cable-stayed part was designed as a “tripod” made by pylons having circular cross-section and rigidly connected by two hollow cylindrical-profiled circles.
The experimental campaign has been articulated in several stages, assessing firstly the eventual proclivity of the deck-section to some aeroelastic instabilities, and then optimizing the aerodynamic performance with respect to the choice of the screen porosity. The aeroelastic model of the tower was designed in order to assess the dynamic response of the tower, given the uncommon geometry of it which could have caused unexpected three-dimensional effect, affecting the deck though the stabilizing cables.
The final stage has been recently carried out by measuring the actual behaviour of the footbridge. In fact, the footbridge was built in the time period going from Several accelerometers has been placed throughout the deck, in selected key-points so to be able to accurately reconstruct the dynamical features of the entire bridge, and on the tripod too. The loading type impressed to the structure allowed to assess the footbridge performance and the dynamical properties (frequencies and damping ratios) taking into account all the possible operative conditions.