The Mole Stabilisation


Milford Haven Port Authority


Milford Haven Docks

A Grade 2 listed structure built during WW2 had been damaged/eroded by tidal and wave action. A section of wall forming part of the facing of the Mole structure at Pembroke Dock had collapsed due to suffering from scouring/undercut at bed level. The Mole, which is constructed from concrete bagwork, is sensitive to vibration and disturbance and had to be repaired with great care.  Access was also extremely limited.

Safety was of prime concern due to the potential collapse of sections of wall, and temporary works had to be designed and installed to prevent this and ensure safety was maintained. This consisted of temporary rock netting in advance of the works to ensure stability of the existing bagwork. In addition, monitoring of the wall was carried out throughout to warn of any movement.

Works involved:

  • Construction of a temporary raised working platform at the base of the structure to extend the intertidal working window.
  • Consolidation of the ground beneath the structure by pressure grouting to create a stable foundation.
  • Breaking out original damaged bagwork.
  • Construction of a new concrete bagwork to match the original incorporating stainless steel dowells and pinning.
  • Pressure grouting behind the new bagwork.
  • Casting new concrete capping/plinth.

All works carried out in line with conditions set out by the Marine Licensing Authority. The works involved liaison with Natural Resources Wales in order to obtain marine licences, and works to the Mole required Listed Building Consent to be obtained. We developed methods of working which met all conditions specified in the Marine Consent.