Raising the viaduct
A viaduct soaring twice the 141m height of the Sydney Harbour Bridge is taking shape with the help of hydraulic technology from Enerpac. The Eiffage/Millau viaduct - with a total height of 343m - is expected to be the highest viaduct in the world when it forms the final link of the A75 autoroute from Paris to Barcelona.
Easily able to accommodate the Eiffel Tower under its tallest point, the multi-span, cable-stayed viaduct soars over the Tarn Valley in southern France, avoiding the need for a tunnel and scarcely affecting the environment.
Enerpac was awarded the contract to supply the hydraulic system for lifting the viaduct’s temporary piers and pushing the bridge decks. Once a pier has been raised, the machinery including the hydraulic system is disassembled and moved to the location for installation of the following pier. The lifting process must be very strictly controlled so the hydraulic cylinders are fitted with an internal position transducer. Similarly the pressure lines have pressure transducers. All the information is brought together at a control panel which manages the data and sends orders to the electro valves, the raising of the cylinders being executed from within an established program.
Each cylinder has its own hydraulic pump so, if necessary, each cylinder can be operated individually, always provided that an exhaustive protocol of request for, and granting, permission is carried out from the central application.
Source: Building Products News.
7-Jul-2003