Benecia Bridge

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.