Stabilization of Rock Face with Rock Bolts

Notre Dame de la Garde Basilica is located on a hill which has on one side a very steep slope. Due to atmospheric exposure and subsequent weathering, this steep rock face had become unstable and had to be extensively reinforced.

Context

The Basilica is built on the highest natural point in Marseille, on the southern side of the old port. The hill has a height of approximately 160m.

DYWIDAG has been awarded by the general contractor SIMECO, a contract to supply all of the anchors necessary for stabilizing the rock face. Since the customer attached great importance to receiving a package solution, SAGGAM, the local representative of DYWIDAG, supplied not only the anchors, but also the mesh with its total surface area of 1,600m² that was used for stabilizing the rock as well as 1,000m of strand.

Solution

For stabilizing the rock face, SAGGAM supplied a total of 455 DYWIDAG Gewi Rock Bolts directly onto the job site.

The DYWIDAG Gewi Rock Bolts with their total length of 1,300m were used for securing the protective mesh, which was attached to the rock face. The DYWIDAG Gewi Rock Bolts were bored into the rock in individual lengths of approximately 3m, post-tensioned and subsequently injected with grout.

The fact that the work had to be executed directly at the rock face constituted a major challenge during this project. The anchors were installed using climbing ropes from which the technicians rappelled down the rock face.

Due to DYWIDAGs package solution and to the excellent co-operation of all parties involved, the job was completed quickly. DYWIDAG is pleased to have contributed to preserving one of Marseille’s major landmarks.