Complex lifts in a confined space were the order of the day high up in the Italian Alps. Photo: Autovictor
The Aosta Valley is north of Turin, Italy, which borders both France and Switzerland. The mountainous region features many bridges which, at some point, must be replaced.
This project required the removal of an existing Bailey bridge. It is a steel lattice bridge built up from prefabricated modular sections which, while usually temporary, can also serve as a permanent installation. Designed by Donald Bailey, a civil servant in the UK War Office, his bridges are well-known from use by allied forces in the Second World War to replace damaged river and other crossings. They are still built in the UK, by Mabey Bridge.
A new concrete replacement was already in place alongside the old one before its removal. Dismantling the old bridge involved a series of tandem lifts completed by Italian lifting specialist Autovictor.
The 500 tonne Demag and 400 tonne Liebherr cranes lifting the main span of the old bridge in tandem. Photo: Autovictor
Autovictor chose a 500 tonne capacity Demag AC 500-2 and a 400 tonne Liebherr LTM 1400-7.1 from its rental fleet. Both the large wheeled mobile telescopic cranes completed the work in a confined area with precipitous drops and almost no available space to manoeuvre.
Aerial view showing how little space there was with one of the cranes having to be wedged up against the mountainside. Photo: Autovictor
Getting going
To start, the first bridge span was lifted using both cranes, translated sideways and temporarily positioned at the opposite side of the work area. One crane remained partially under load to ensure stability throughout the operation.
The cranes were then reconfigured to take over the longer bridge section, which was then lifted again and moved into position on the new bridge structure. Remaining elements of the old bridge were separated into smaller sections to reduce size and weight and optimise handling.
One of the lifts required the crane to be positioned directly against the mountainside so it could lift the largest bridge section, rotate it in the restricted work area and then position the section in front of the crane.
Throughout the project, lifting precision, co-ordination among the crews and engineering expertise were essential to managing the dismantling of the bridge in the challenging Alpine environment.
Dismantling the old modular Bailey bridge. Photo: Autovictor