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
recommendation
RECOMMENDATION: Recommend to the Board of Directors to:
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 the temporary removal of conflicting utilities and appurtenances on the exterior of the digesters, replacement of damaged concrete around the dome base, and installation and tensioning of new tendons.
TIMING CONCERNS
Delaying the project award will allow further corrosion of the tendons to occur.
RAMIFICATIONS OF NOT TAKING ACTION
The tendons will continue to corrode which could lead to structural failure of the digester domes.
PRIOR COMMITTEE/BOARD ACTIONS
N/A
ADDITIONAL INFORMATION
OC San advertised Project No. P2-137A for bids on March 27, 2024, and one sealed bid was received on May 15, 2024. A summary of the bid opening follows:
|
Engineer’s Estimate |
$ 2,600,000 |
|
Bidder |
Amount of Bid |
|
Structural Preservation Systems, LLC |
$ 2,597,864 |
|
|
|
The bid was evaluated in accordance with OC San’s policies and procedures. A notice was sent to the bidder on June 12, 2024, informing them of the intent of OC San staff to recommend award of the Construction Contract Agreement to Structural Preservation Systems, LLC.
Staff recommends awarding a Construction Contract Agreement to the lowest responsive and responsible bidder, Structural Preservation Systems, LLC, for a total amount not to exceed $2,597,864.
CEQA
The project is exempt from CEQA under the Class 1 categorical exemptions set forth in California Code of Regulations section 15301. A Notice of Exemption was filed with the OC Clerk-Recorder for P2-137 after the OC San's Board of Directors approval of the Professional Design Services Agreement on March 23, 2022.
FINANCIAL CONSIDERATIONS
This request complies with the authority levels of OC San’s Purchasing Ordinance. This item has been budgeted (Budget FY 2024-25 and 2025-26, Section 8, Page 74, Digesters Rehabilitation at Plant No. 2, Project No. P2-137) and the budget is sufficient for the recommended action.
ATTACHMENT
The following attachment(s) may be viewed on-line at the OC San website (www.ocsan.gov) with the complete agenda package:
• Construction Contract Agreement
• Presentation
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