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 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.
||Excavated Material (m3)
||Concrete Volume (m3)
|Caissons on West Breakwater
|Caissons on East Breakwater
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