Single lift for 34t bridge

The 34t bridge on the Autoroute du Nord, the most frequently used French highway, had to be removed at night to minimize traffic congestion.  The traffic was diverted via the east and west rest stops. This allowed the dismantling planned as part of the highway renovation in both directions to be carried out without additional time pressure.

“The Tadano ATF 400G-6 proved to be exactly the right choice during the entire operation, for a number of reasons, from its load-swing-free lifting to the strongest main boom in its class and its exceptional lifting capacity. The lifting capacity ensures that the six-axle model, compared to competitor models, is less likely to reach its limits when lifting heavy loads. This allows drivers to work in a more relaxed atmosphere; the consequences are fewer operating errors and less material damage,” said Tadano.

Only a few hours were needed for the setup, especially the mounting of the 96t counterweights on the crane – although with the ATF 400G-6 the first 25t counterweight can be activated with the first lift, saving time – for lifting the overpass, and then taking down the all-terrain crane.

Positioning and moving the crane with the 96t counterweight was also effortless. And this despite the challenging environmental conditions. For one thing, visibility was difficult. And for another, there was a strong wind – an additional challenge that slowed down the work.

The bridge – 35m long, 5m wide, 5m high – was lifted in a single piece in one lift and set down at the rest stop in the construction site area. For this to happen, the overpass (created in 1970) was fixed by means of a fourfold reeved double hook and enough spaced fastenings to counteract any load swing. The lift adjuster that was used also made a significant contribution to achieving an easy lift. For example, the working radius remained constant during operation and the overpass was raised without swinging forward.

A significant relief for crane operator Karim Idjouadjene: he didn’t have to constantly look at the instruments to monitor the radius and was able to focus his full attention on the load, its environment, and the directions given by colleagues. The maximum lifting height was 20m, the boom was telescoped to 35.5m, and the lifting time was 15 minutes.