In central Italy, BESIX and our Italian partner DONATI are doubling 3.1 kilometres of State Road 318 on behalf of the Italian Highway Authority ANAS S.p.A. Alongside the Casacastalda and Picchiarella tunnels and the Calvario bridge, another notable feature of the project is the Tre Vescovi viaduct. Last weekend, our colleagues in Italy launched and put into place the third and last segment of the viaduct.
1, 2, 3 go!
The Tre Vescovi* Viaduct is a 129.5-meter long, 11.45-meter-wide mixed steel-concrete structure, divided into three segments of 37 meters, 55.5 meters, and 37 meters. The first segment of the viaduct was launched at the end of February. Mid-May, our Italian team tackled the second segment and last weekend they finalised the launch of the third segment.
Each segment was assembled on one side using a steel nose for the launch and moved horizontally to free up space for the next segment. This process was repeated for all three segments.
Engineering insights
The spindle bar system was used to launch the bridge segments. Hydraulic jacks gradually moved and positioned the bridge parts, allowing for construction from one side only. The system moves about 12 meters a day and is ideal for bridges on slopes over 5°, ensuring controlled and precise launching.
The bridge, weighing 458 tonnes (367 tonnes for the viaduct and 91 tonnes for the metal bars), spans 11.45 meters in width, with a 9.35-meter road width accommodating two traffic lanes.
The road ahead
With all segments in place, the bridge deck now spans the valley completely. The team in Valfabbrica will proceed with the next phase of the bridge construction. They will now lift the viaduct with hydraulic jacks to allow the removal of the temporary sliding bearings and to place the viaduct on the definitive seismic bearings. Once this is done, the concrete deck will be poured and the definitive guardrail will be installed. The final step will be the laydown of the asphalt layer.
“The Valfabbrica project is an essential infrastructure for the region as it will greatly improve the connectivity and traffic flow between the cities of Perugia and Ancona. State road 318 is a crucial east-west axis in Italy, passing through the scenic Umbria countryside, including Valfabbrica, after which the project is named. BESIX and our local team are very proud to participate in this project. The finalization of the launching phase is a major milestone for the construction of the Tre Vescovi Viaduct.” Hervé Jourquin, Project Manager
* The name of the viaduct, Tre Vescovi, refers to a ravine below called "Fosso dei tre Vescovi" (Ravine of the Three Bishops), which in medieval times marked the boundary between the dioceses of Assisi, Nocera, and Gubbio (each diocese having its own bishop).