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HomeMy WebLinkAbout11 Airport Tank Rehab AGENDA ITEM #11 Page 1 of 2 MEETING DATE: December 1, 2021 TO: Board of Directors FROM: Neil Kaufman, Water System Engineer SUBJECT: Award of a Contract to Perform Rehabilitation of the Airport Water Storage Tank APPROVED BY______________________________ Brian C. Wright, General Manager RECOMMENDATION: Authorize the General Manager to execute a contract with DN Tanks to perform rehabilitation of the Airport Tank in an amount of $348,000, plus a ten percent change order allowance for a total authorization not to exceed $383,000. BACKGROUND: The Airport Tank is a 500,000 gallon partially buried pre-stressed concrete tank that was constructed in 1980. During the summer of 2010, DN Tanks performed repairs to the dome ring of the Airport Tank under an emergency declaration. The dome ring is located where the vertical walls and roof join together and is critical to supporting the roof structure. The work was completed on-time and with no change orders. In 2010, it was noted that the tank was experiencing concrete spalling from the roof on both the interior and exterior surfaces. However, this issue was not considered critical to the structural integrity of the tank at that time and was not included in the scope of work under the emergency. Over the last ten years, Water Department staff have conducted periodic concrete patch maintenance work to the roof and sidewall structures of the tank. Based on recent inspections performed in the fall of 2020 and summer of 2021, the Airport Tank requires substantive repairs to the roof system along with replacement of many of the interior steel components such as the access ladder and overflow structure. Page 2 of 2 It is expected that the rehabilitation work will require about six weeks to complete. While the work is being performed, the Airport Well will be unavailable to serve customer demands. The concrete work also requires that ambient temperatures do not go below freezing for extended periods of time. Considering these operational and temperature restrictions, successful completion of the rehabilitation work is essentially limited to the project window of April-May or late September-October. Recognizing the specialized nature of the rehabilitation and forecasted workloads, award of the contract at this time will allow for the selected contractor to schedule the work for April-May 2022. The District publicly advertised a request for bids for the Airport Storage Tank Rehabilitation Project. A bid opening was held at 2:00 PM on November 17, 2021. One bid was received: TOTAL AMOUNT OF BID Bidder Location Amount Responsive DN Tanks El Cajon, CA $348,000.00 Yes FISCAL IMPACT: The price proposal from DN tanks is $348,000. It is recommended that a ten percent change order allowance of $35,000 be established for a total authorization of $383,000. Storage tank rehabilitation and maintenance is a component of the 10-year water capital improvement plan. The FY2021 approved Water Budget included approximately $160,000 for water storage tank coating replacement. The tank coating replacement project was placed on hold in preparation for this larger rehabilitation project. The approved FY2022 Budget for Water Utility includes $949,000 for this activity with the Airport Tank identified as one of the scheduled projects.