Brighton Breakwater Remediation

United Kingdom

Summary

  • Year
    2017
  • Client
    Hemsley Orrell Partnership
  • Location
    United Kingdom
  • Scope of Work
    MMA was awarded the full remedial scope for 23 caissons as part of the bi-annual maintenance program.

Project Overview

The breakwater surrounding Brighton Marina consists of 110 ballast filled caissons +10m radius. For stability and design-life-extension, it was required to remove the existing caisson ballast and re-fill them with mass pour concrete.

MMA Scope

MMA was awarded the full remedial scope for 23 caissons as part of the bi-annual maintenance program.

A total of 8,225m3 of sand was excavated and 18,513m3 of concrete was batched on site and poured into the caissons.

The East breakwater works were executed with a marine spread (5 barges) in the marina and a long reach excavator on a jack-up barge. The excavated sand was reused as aggregate for the concrete mix. A batch plant with an output of 30m3/hr was used to produce and pump concrete from a barge into the emptied caissons.

The West breakwater works were land based, a suction truck was used to remove the sand from the caissons. The sand was used in the concrete mix, which was batched on site by MMA.

Technical Details

  Excavated Material (m3) Concrete Volume (m3)
Caissons on West Breakwater 2908 9120
Caissons on East Breakwater 5217 7393

MMA Innovation / Value Added

  • Marine spread for excavation and mixing spread
  • Re-use of excavated material as concrete aggregate
  • Reduction in traffic through Marina due to on-site batching

Key Equipment / Installation Method

  • Twin shaft mixer
  • Floating cement barge
  • Jack-up barge
  • Hopper barge
  • Containerised cement silos
  • Long reach excavator
  • Suction excavator
Category: United Kingdom