Charlestown Drydock

AK Industrial Services performed Ultra-High-Pressure (UHP) hydrodemolition 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.
• Close proximity of the caisson, a very tight inside corner and an arching sloped wall
• Sloped concrete walls (making hydrodemolition challenging)
• Inside corner required 24” deep hydrodemolition
• Working in a small area with the mechanical demo contractor

Services Performed

The AK team needed to perform hydrodemolition on 100% of the floors and walls within 10′ of the caisson. The average depth of hydrodemolition was 10″, with 24-26″ required at the new caisson installation site.

For the rest of the drydock, mechanical demolition was performed, but hydrodemolition was used for the first 8” and the last 2”. This was because the design engineer wanted:

• • To mitigate micro cracking
  • To provide a highly bondable profile with the existing concrete
  • To ensure that all unsound concrete was removed

Successful Results

Using hydrodemolition created an excellent bonding surface for the new concrete. The AK team was able to remove unsound concrete from areas where there had been large cracks and deterioration, and by using hydrodemoliton, they were able to eliminate all dust, unlike mechanical demolition. Additionally, the AK team finished ahead of schedule.