Project Overview
AK Services performed Ultra High Pressure (UHP) hydro demolition of the wing walls at Old Ironside Drydock in Charlestown, Massachusetts.
Key Challenges
- Protecting a nearby historic caisson from damage, as a significant amount of the work took place next to the USS Constitution Museum.
- The challenges of close proximity of the caisson, a very tight inside corner and an arching sloped wall
- The sloped concrete made the hydro demolition challenging
The inside corner required 24” deep hydro demolition
- The sloped walls.
Working in a small area with the mechanical demo contractor
Services Performed
Within 10 feet of the caisson all floors and walls had to be 100% hydro-demolition: 10” in general and 24-26” at the location for the new caisson to be installed.
For the rest of the dry dock, mechanical demolition was performed, but hydro demolition was used for the first 8” and the last 2”. This was because the design engineer wanted:
- to mitigate micro cracking
- to provide a hightly bondable profile with the existing concrete
- to ensure that all unsound concrete was removed
Successful Results
- Provided an excellent bonding surface for the new concrete
- Removed unsound concrete at areas where there had been large cracks and great deterioration
- Finished ahead of schedule – before the concrete was ready for placement
- Eliminated all dust, unlike the dust created from the mechanical demolition
