FROM: Robert Thompson, General Manager
Originator: Mike Dorman, Director of Engineering
SUBJECT:
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DIGESTER P AND R DOME TENDON REPAIR, CONTRACT NO. P2-137A
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GENERAL MANAGER'S RECOMMENDATION
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RECOMMENDATION:
A. Receive and file Bid Tabulation and Recommendation for Digester P and R Dome Tendon Repair, Contract No. P2-137A;
B. Award a Construction Contract Agreement to Structural Preservation Systems, LLC for Digester P and R Dome Tendon Repair, Contract No. P2-137A as part of Digesters Rehabilitation at Plant No. 2, Project No. P2-137, for a total amount not to exceed $2,597,864; and
C. Approve a contingency of $259,786 (10%).
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BACKGROUND
The Orange County Sanitation District (OC San) has 18 anaerobic digesters at Plant No. 2 that were built from 1959 through 1979 and are used to convert sludge to biosolids and biogas for reuse. Anaerobic digesters are large enclosed concrete structures with pumping, mixing, heating, and gas handling systems. During the design phase of Digesters Rehabilitation at Plant No. 2, Project No. P2-137, investigations were performed on all digesters to assess the level of external concrete rehabilitation needed.
RELEVANT STANDARDS
* Comply with California Public Contract Code Section 20103.8, award construction contract to lowest responsive, responsible bidder
* 24/7/365 treatment plant reliability
* Protect OC San assets
PROBLEM
During digester concrete rehabilitation investigations, it was found that the post-tensioned tendon system to support the domes for Digesters P and R had significant corrosion, while other digesters with the same system did not show the same signs of corrosion.
PROPOSED SOLUTION
Award a construction contract agreement for Digester P and R Dome Tendon Repair, Contract No. P2-137A. This project will add a new post-tensioned tendon system to replace the corroded tendon system that supports the domes for Digesters P and R. This will entail ...
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