Reinforcement work on the M2 and M4 blocks of the Artouste penstocks. In addition, the repair of a foundation pad of pylon 2 of the cable car is integrated into this operation.

During the external inspection of the Artouste penstocks in 2023, deterioration was noted on the M2 and M4 massifs. The deterioration noted are cracks on the nose of the massifs at the level of the downstream face and the cheeks on the right and left banks. The M2 massif had already been the subject of crack repairs in the same areas. The source of these cracks is therefore ancient and deeper than the simple phenomenon of cracking with freeze/thaw and time. Indeed, these degradations reflect the movement of the CF within the massifs and therefore the overstresses imposed on the massifs. The pipes tend to rise during the phenomena of expansion/contraction and consequently carry with them part of the massifs.

These crack lines are, more or less, the same between the left and right side panels. Cracks can also be observed on the downstream sides of the massifs.

The contract therefore includes the study, design and construction of a reinforcement to stabilize the massifs in the face of penstock uplift. To do this, it will be necessary to press the upper face of the massifs towards the ground thanks to anchors and a concrete shell. The reinforcement should inhibit any further movement according to the red arrows in order to avoid a total dislocation of the massif and a loss of its weight function.

The concrete shell must be able to receive the thrust forces of the block and transmit them to the nails. The nails will have to make it possible to resume these efforts in the field.

In addition to the two reinforcements, a repair on a foundation pad (upstream on the left bank) of Pylon 2 of the cable car must be carried out. The repair consists of stitching the pedestal down to the sound concrete and then creating a concrete lining in front of the existing one (vertical and horizontal faces).