France: construction of two decks for the Petit-Lay viaduct
As part of the construction of the Petit-Lay viaduct at Bournezeau for authorities in the Vendée region, Eurovia Béton has built two 190-metre decks following the construction of supports in 2015.
The decks consist of a steel framework topped by a reinforced-concrete cellular block. The block is made with precast slabs that were bolted together and bolted to the metal frame.
The slabs for the first deck were installed using a crane positioned on unbolted slabs already in place. The slabs were supplied to the crane under the crane hook by a delivery trolley travelling to and fro on the frame. Once the slabs on the first deck were bolted, the first deck was used as a platform for delivering slabs to the second deck.
To carry out these operations, mobile cranes were equipped with distance spacers to reduce the size – and, therefore, the weight – of the lifting systems. A provisional guard rail fastened to the crane’s slings (for work carried out on the first deck) was re-used in order to minimise the handling of temporary guard rails.
For the second deck, the guard rails were moved manually.
A year into the project, the equipment phase was launched, including cornices, culverts, safety barriers, and pavements.
Work was carried out from July 2015 to July 2016.