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TO: HONORABLE MAYOR AND MEMBERS OF CITY COUNCIL
FROM: DIRECTOR OF PUBLIC WORKS
DATE: OCTOBER 15, 2002
SUBJECT: SAN RAMON DRAINAGE AND LANDSLIDE STABILIZATION PROJECT - REQUEST FOR ADDITIONAL FUNDING
Staff Coordinator: Nicole Jules, Sr. Engineer
On October 2, 2001 a construction contract was awarded to Colich & Sons in the amount of $2,250,556.00 with a contingency amount of $157,540 for a total authorization of $2,426,096. It now appears that to complete the construction an additional funding in the amount of $140,000 is required
The San Ramon Drainage and Landslide Stabilization project is nearing completion.
The storm drain pipeline is constructed, the outlet structure is complete and the contractor has resumed importing fill material to finalize the buttress slope.
To date, the project has passed it's original contract completion time, has been delayed 130 working days and has expended approximately 80% of the contract budget. The project delay is due to several unforeseen occurrences. While excavating for the placement of the outlet structure, the contractor exposed a failure plane on the eastside of the canyon. This failure plane created an unsafe working condition for the contractor, subsequently preventing the construction of the outlet structure as designed. To create a safer construction environment, the outlet structure was relocated away from the failure plane and the failure plane had to be stabilized against future failures.
The outlet structure redesign was completed in 4 months. This five-month delay pushed our completion date from July 24, 2002 to December 15, 2002. The revised outlet structure has been relocated further downstream and constructed with a pair of retaining walls, backfilled with concrete slurry, to buttress and protect the exposed failure plane from future erosion.
This need to relocate the structure has significantly changed the scope of work. It increased the area of impact to native vegetation, increased our volume of import for the landslide stabilization created an increase to contract bid items, and created a maintenance and easement impact to 2 additional homeowners,
The construction related activities associated with the outlet structure redesign will cost approximately $90,000.
In addition to the construction related activities, an existing storm drain pipeline, leading from San Ramon Drive into the San Ramon canyon, was discovered to have multiple failures in the invert. The initial failures were discovered at the outlet into the San Ramon Canyon. Discovering this deteriorated pipeline raised concerns due to storm drain water seepage into the hillside. Proactive measures were immediately taken by investigating further the condition of the pipeline.
Public works utilized the services of National Plant Services, Inc., a pipeline inspection/filming company, to videotape the inside of the pipeline for confirmation of pipeline condition. The inspection images confirmed the condition of the pipeline. Attached are copies of the inspection images that show holes in the pipeline.
Subsequent to the filming, informal bids to rehabilitate the pipe were immediately solicited. Two bids were received and results are as follows:
Both Colich & Sons and Sancon Technologies proposed similar pipe rehabilitation processes. The pipe rehabilitation process utilizes trenchless technology to restore pipeline structural integrity. In other words, no excavation is needed to repair the pipe.
The existing pipe is lined with a felt liner that is coated with a thick resin or glue to adhere to the existing pipe. This liner is manufactured with a polyurethane outer coating to protect against saturation and to provide a smooth surface on the inside. This felt liner is like a new smooth pipe inside the old deteriorated pipe. This liner creates a seamless, joint-less and leak-proof pipe throughout the entire length. This process is usually completed in a day, depending on the length of the existing pipe. This process is widely used worldwide and has been utilized for over 30 years. Copies of the proposal are attached to this report.
The rehabilitation of the San Ramon Drive pipeline is a separate project from the San Ramon Drainage and Landslide Stabilization project. Although separate, awarding this work to Colich & Sons under their current contract as a change order will reduce storm drain water seeping into the hillside.
Staff recommends utilizing Colich & Sons for the pipe rehabilitation project because they provided the lowest costs, and are currently mobilized at the site for ease of access, construction and prompt response to the problem.
Adopting this staff recommendation will provide the necessary additional funding for construction improvements to complete the San Ramon Drainage and Landslide stabilization Project. Additionally, this recommendation will grant a change order to Colich & Sons for the rehabilitation of the San Ramon Drive pipeline. The total cost of construction, including engineering services, now stands at $3,494,650. Including the San Ramon Drive pipeline rehabilitation will increase the project cost to $3,544,650.
Proceeding with staff recommendation to increase funding for the construction improvements by $90,000 and including the rehabilitation of the San Ramon Drive pipeline for $50,000, will result in a total budget amount of $3,544,650. The funding source for this budget increase is the miscellaneous drainage fund. Funds will be reprogrammed from the Miscellaneous Drainage Project to the San Ramon Drainage and Landslide Stabilization project.
San Ramon Drive Pipeline Inspection Images