AKIS performed abrasive jet cutting to a drive shoe for removal from a crippled drilled shaft casing at Benecia Bridge in California.
Key Challenges:
- Relief of the potential energy remaining in the crippled shoe;
- All work had to be done remotely; team members could not enter the caisson during the operation;
- Stored up energy, hence the beveled cuts and doing the first piece
Permitted Confined Space:
Gases:
- Hydrogen Sulfide – explosive; therefore, could not use “hot work” – sparking or flame type cutting
- Hot Work restricted space
Monitor for Oxygen:
- 100′ deep into a caisson = permitted confined space
- The actual cutting had to be done remotely
Services Performed
- 14′ caisson cut shoe
- Depths at 100′
- 14-8’ diameter crippled drive shoes
- AK Team cut at an angle to provide relief for the stored energy in the steel – cut length was 3-3/4”
Internal:
- Cut and remove the first section = the relief
- Then went back in, and cut all the verticals
- Then went in and cut the horizontal ring cut, removing each piece as we cut
- Used pulverized garnet as the abrasive
- All cuts were performed at an angle
Successful Results
The AKIS team successfully cut and removed all 14 sections of crippled caissons for two separate contractors – Kiewit Pacific and Condon Johnson. The project owner was the California Dept. of Transportation.
