Col du Mollendruz

Rehabilitation of a dry stone wall - Col du Mollendruz


Direction générale de la mobilité des routes du canton de Vaud (DGMR) 


Site works: from the 15th August to the 10th December 2017 

Total costs

585 k EUR

Project description 

The dry stone wall retains the ground supporting the cantonal road RC 151, 1km from the Col du Mollendruz in the commune of Mont-la-Ville.


  • Crash barrier no longer in conformance with the safety standards.
  • Deterioration of the concrete and corrosion of the reinforcement of the ground beam which supports the crash barrier.
  • Bulges present at the base of the wall.
  •  Presence of vegetation over a significant proportion of the wall.
  • Presence of crumbled or disintegrated stones.


  • High pressure jet washing of the wall.
  • Isolated removal and replacement of damaged stones.
  • Complete dismantling of the bulging sections of wall up to a height of 5m. Installation of a nailed wall which supported one of the two lanes of road, permitting alternating circulation of road traffic throughout the works. These works included the installation of a concrete foundation slab, inclined at 30° at the base of the section which had been completely dismantled.
  • Installation of a concrete ground beam and foundation at the top of the dry stone wall (height 1.4m, width of foundation 1.7m). The purpose of the ground beam is to absorb any traffic impacts without transmitting these to the wall.
  • Installation of drainage allowing water to drain across the ground beam.
  • Reconstruction of the road surface and installation of the guard barrier.


  • Length of ground beam and dry stone wall: 101.5m
  • Height of wall: between 2 and 5m
  • Length of the crash barrier: 120m
  • Area of nailed wall: 140m2
  • Area of dry stone wall replaced: 140 m2 

Services provided

All project stages from scheme design to construction in line with the SIA phase definitions.

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