Stay simple, stay nice at Ostellato

The Ferrara waterway, connecting this historic town with Comacchio on the Adriatic Sea is being upgraded: section widening and straightening as well as higher clearance has called for the replacement of most of the existing bridges. On the outskirt of Ostellato the conditions were appropriate for a medium span stay cable road bridge having the peculiarity of a curved girder with a plan and crest radius of 1000 metres. The structure had to be cost efficient, because it was offered as an alternative design to an awkward but smaller tender solution within the same budget. Concrete towers had to be of the inverted Y shape to resist lateral forces given by the horizontal radius, steel frames have been cast into the upper concrete section of the towers to facilitate positioning and erection of the 48 stays. The 14m wide deck sports the classical composite design with plated girders running at both sides and transverse beams at 4 metres centre; with an height of 1.5m circa for the 130 metres span, the resulting slenderness is considerable and associated with the double curvature gift the structure with elasticity and lightness.