HomeMy WebLinkAbout09.a. (Handout) Declare emergency re Sludge Blending Tank9Q.
(Handout)
Sludge Blending Tank
Emergency Repairs
Brad Leidecker, P.E.
Associate Engineer
June 4, 2014
11 Central Contra Costa Sanitary District
Protecting Public Health and the Environment
Sludge Blending Tank
• 1966 -Built as prestressed concrete digester tank
• 1972 - Repurposed as centrate thickener (5A design)
• 1991- Modified to current process as sludge blending tank
• 2004-
Protective coatings project
SBT Failure of Outer Wall
• On Tuesday, May 20, failed gunite layer was
discovered on eastern side of tank
Emergency Actions
•Secured site for safety
• Obtained Structural Engineer
• Hired Demo Specialist (W.C. Maloney)
• Hired Tank Retrofit Contractor (DN Tanks)
• General Manager declared emergency
based on the following:
- Safety for Staff
- Protect equipment in service
Work to date
• Removed imminent safety hazard
• Inspected post tensioned steel rods
Next steps
• Continue evaluation of tank, including similar
cracking on north side of tank
• Perform structural analysis using inspection
findings and work with Tank Contractor to find
appropriate repair
• Perform required repair to end emergency
• Expected timeline - 2 -3 additional weeks
• Potential costs up to $140,000 - $200,000
• Bid contingency project, if needed
I-C
STAFF RECOMMENDATION
• Declare an emergency and ratify the
General Manager's actions under Public
Contract Code 22050 to direct W.C.
Maloney, Inc., DN Tanks, and District forces
to perform emergency repairs on the
damaged Sludge Blending Tank
• Approve supplemental allocation of
$200,00 from FY13 Contingency Budget
J