TO: Board of Supervisors
FROM: Steven Lederer, Director of Public Works
REPORT BY: Frank Lucido, Engineering Manager
SUBJECT: Approve Award of a Construction Contract and Budget Transfer for the "Redwood Road 5.76 Slide Repair Project", RDS 21-05
RECOMMENDATION
title
Award a Construction Contract to "E.E. Gilbert Construction, Inc." for the "Redwood Road 5.76 Slide Repair Project"; and approve a Budget Amendment. (Fiscal Impact: $166,377 Expense; Measure T Non-Operating Special Revenue Fund; Not Budgeted; Discretionary)
[4/5 vote required]
body
BACKGROUND
Heavy rains in February of 2017 oversaturated a portion of Redwood Road near mile post marker (MPM) 5.76 which serves a small number of residents, causing the edge of the roadway to slide into Redwood Creek and roadway distress for about 60 feet directly above the slide and another 80 feet adjacent to the slide area. On January 5, 2022, the board approved $555,746 from Measure T funds to start the investigation and design process for the project.
Two alternatives were considered for this project. The most expensive alternative has an estimated project cost of $1,800,000 and involves drilling deep into competent material, casting concrete piers and constructing a concrete roadway over the piers. While this option allows for a slightly wider roadway and can be constructed over the area that slid it is not recommended as it does not appear to provide good value for that expense. The roadway narrows in many places in the vicinity of the damage and having a localized area that is wider provides little advantage to passing traffic. Since most of the road in this area has not slid, there isn't a need to implement this more expensive option. The recommended option has an estimated project cost of $722,000. It involves drilling into competent material and creating a retaining wall of concrete piers. These piers will be tightly spaced to secure soil in the roadway and take advantage of the existing in place hills...
Click here for full text