To: Members of the Castle Rock Water Commission
From: Mark Marlowe, P.E., Director of Castle Rock Water
Roy Gallea, Engineering Manager
Matthew Hayes, Technical Engineering Manager
Title
Resolution Approving a Construction Contract Between the Town of Castle Rock And 53 Corporation, LLC for the Tank 6B Site Restoration [2803 S. Ridge Rd.]
Town Council Agenda Date: November 7, 2023
Body
________________________________________________________________________________
Executive Summary
The purpose of this memo is to request Town Council approval of a Resolution (Attachment A) approving a construction contract (Exhibit 1) with 53 Corporation for the site restoration at Tank 6B. This project demolished Tank 6B, which had failed due to concrete deterioration from Alkali Silica Reaction (ASR). Staff recommends approving a construction contract with 53 Corporation in the amount of $34,650, plus a Town-managed contingency of $3,465 (10% contingency) for a total authorization of $38,115. This item is before council given the accumulative cost of construction for the demolition of Tank 6B which has now exceeded the Town Manager’s limit of $250,000. The original construction contract for this project was $122,564, however due to an increase in excavation and stockpiling quantities which was not accounted for in the original scope of work and changes in priorities for the rebuilding of this tank, the overall cost of the project has increased to $273,929.
History of Past Town Council, Boards & Commissions, or Other Discussions
Town Manager approved a construction contract with Western Wrecking for $122,564 in March of 2023.
Town Manager approved a construction change order in the amount of $113,250 in September of 2023.
Discussion
The Tank 6B Demolition Project is located on Ridge Road, south of Town. During routine inspections in 2010, deterioration of the roof was observed by operations. Later that year, a structural inspection was conducted by a structural expert. The cause of the deterioration was determined to be an Alkali Silica Reaction (ASR). This is the result of a reaction between the siliceous minerals in the aggregate and the alkalinity of the concrete. Due to the high risk of structural failure, the tank was taken out of service and scheduled for demolition.
The demolition project was awarded to Western Wrecking in March of 2023. The scope of the project included removal of the tank, capping the existing fill and drain pipe. The original scope of the demolition project did not include backfilling the tank site. The backfill was not included due to the planned replacement tank at the site.
Change Order 1 with Western Wrecking included the cost addition for a soil excavation and storage quantity increase of 4,300 cubic yards, and an increase in erosion control and restoration. The initial excavation quantity take off was based off of record drawings. As the contractor progressed through the demolition of the tank, more excavation was required.
Based on recent conversations with the operations team and coordination with planned development in the Meadows area, staff has determined that a second blue zone tank in Meadows area is a higher priority. The second tank is needed to support summer demands and allow for routine inspection and maintenance on the existing tank. Due to this change in priority, the hole left from the removal of Tank 6B must now be filled. Western Wrecking provided a cost for the backfill during the change order process, but staff felt that their number was not reasonable. Additional bids were requested from other contractors.
Budget Impact
Town staff contacted two additional contractors for pricing to backfill the tank. A summary of the bids is shown below.
|
Contractor |
Bid |
|
53 Corporation |
$34,650 |
|
Global |
$116,150 |
|
Western Wrecking |
$171,000 |
Funding for this project is available in the approved 2023 budget. The project will be funded from the Tank Rehab and Replacement account (Account No. 210-4275-442-75-33). 53 Corporation’s cost is $34,650. Staff requests an additional $3,465 (Town managed 10% contingency) be authorized for a total project authorization of $38,115.
The original contract and Change Order #1 with Western Wrecking had a total cost of $235,814 which was the lowest project cost based on the original bidding with the next lowest cost being XXX. The addition of this construction contract would be required regardless of which contractor had been awarded the original contract and will place the total project amount over Town Manager approval. As a result, staff is seeking Council approval.
Staff Recommendation
Staff recommends Town Council’s approval of the contract between the Town of Castle Rock and 53 Corporation, for the Tank 6B backfill in the amount of $34,650 plus a 10% Town-managed contingency of $3,465 for a total authorization of $38,115.
Proposed Motion
“I move to recommend to Town Council approval of the Resolution as presented”
Attachments
Attachment A: Resolution (Not Attached)
Exhibit 1: Agreement
Attachment B: Location Map