Dating from 1962, La Daille’s pylons used to occupy a considerable amount of space on the slopes. The construction of the new gondola lift however, means that the number of pylons on the line is able to be reduced from 16 to 12, thereby reducing the environmental impact.
A wide range of materials
All the materials for the future gondola lift line are stored on the La Daille site.
On the right: the footings. These form the base of the pylons. This section here is underground. The reinforcing rods (on the left) into which the tower anchors will be sunk, will come on top of these foundations.
Next, the bolt frames to which the pylon towers are affixed. Each bolt frame is pre-adjusted to the exact dimensions so that the pylon can be easily screwed on top.
These are assembly bolts for both departure and arrival stations.
The towers were transported to Val d’Isère in multiple sections on articulated lorries. The tower dimensions are precisely defined according to their position along the line.
The largest tower measures 1.50m in diameter and will be placed under the 3rd pylon.
The towers are assembled by helicopter (Super Puma). During helicopter transportation, an engineering worker at the top of the ladder guides the assembly process.
On the right: the cable feeding brackets which are positioned on the top of pylons. The job of these brackets is to hold the cable up during line maintenance, as well as to have multiple accessories fixed to them (safety rings, electrical boxes, lighting, etc…).
Expert answer :pylon size
How are the pylon sizes calculated?
It’s a design calculation carried out by Ingélo, the engineering departement for Compagnie des Alpes group, and POMA.
It all depends on the height of the pylon, the load it has to bear, and the distance between each pylon. The distances can extend up to 230 metres, while others are closer together. In La Daille, we ensured the pylons were installed in such a way as to reduce the impact on the ski run, compared to the old ones, which were much larger.
On the right, a future pylon installation site.
A hole will soon be dug, after the teams will install the reinforcement rods (foundations), then form the base. Before pouring the concrete, a surveyor will come to measure and check the installation to the nearest millimetre. The goal is to end up with as little deviation from the plans as possible.
To remember: to reduce environmental impact, the multipair cables will be buried underground. This involves digging a trench that is almost 2 kilometres long.