To: Board of Supervisors
Department or Agency Name(s): Sonoma County Public Infrastructure
Staff Name and Phone Number: Johannes J. Hoevertsz, 707-565-2550
Vote Requirement: Majority
Supervisorial District(s): Fifth
Title:
Title
Wohler Road Bridge over the Russian River Seismic Retrofit Project, C01136, Construction Contract Change Orders and Construction Contract Increase
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Recommended Action:
Recommended action
Approve and authorize the Director of Sonoma Public Infrastructure to execute construction contract change orders in a total amount not to exceed $3,438,000 and approve an increase to the Wohler Road Bridge over the Russian River Seismic Retrofit Project construction contract in the same amount, for a revised total not-to-exceed contract amount, including contingencies, to $26,232,083.
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Executive Summary:
The Department of Public Infrastructure (SPI) requests Board approval to authorize the Director of SPI to execute construction contract change orders in a total amount not to exceed $3,438,000 for the Wohler Road Bridge over the Russian River Seismic Retrofit Project (C01136). These change orders are necessary to complete construction of the bridge superstructure. If approved, this action will increase the total, not-to-exceed contract amount, including contingencies, to $26,232,083.
Discussion:
The Wohler Road Bridge Seismic Retrofit Project (Project) is the largest and most complex bridge project undertaken by the County of Sonoma. The Project retrofits the existing historical, seismically deficient one-lane Wohler Road Bridge (Bridge Number 20C-155), with a new lightweight concrete deck, seismic isolation bearings, steel truss reinforcement, and foundation reinforcement.
On February 6, 2024, the Board awarded a construction contract for the Project to Ghilotti Construction Company, Inc. in the amount of $17,994,621 and authorized a 10% contingency in the amount of $1,799,462, for a total not-to-exceed contract amount of $19,794,083.18. On December 16, 2025, the Board authorized the Director of Sonoma Public Infrastructure to execute a construction contract change order up to the amount of $2,300,000 due to differing site conditions and schedule acceleration. On March 24, 2026, the Board increased the contract amount by $3,000,000 to fund Contract Change Order (CCO) fourteen (14) and fifteen (15) for dewatering method changes.
SPI now requests authorization to execute construction contract change orders in a total amount not to exceed $3,438,000 to pay for changes to the superstructure construction. Approval of this item will increase the construction contract amount by $3,438,000, resulting in a new total not-to-exceed contract amount, including contingencies, to $26,232,083
The bridge superstructure includes all components above the foundation, piers, and abutments, including the steel beams, bridge deck, and upper steel truss elements. During preparation for superstructure work in spring 2025, inspection of the underside of the deck identified significant section loss and pitting in floor beams and connection plates. In addition, the truss has shifted and needs to move back to its original location.
These conditions require additional temporary steel strengthening, structural jacking, access pad reconstruction, and reinstallation of scaffolding to safely complete the originally planned retrofit work. The time required to evaluate conditions and develop revised construction approaches has extended the project into a third construction season, resulting in additional cost escalation for certain work items.
The additional cost for the change order scope will exceed the 10% statutory limit for individual change orders. Changes exceeding the statutory limit ordinarily require competitive bidding, unless competitive bidding would be unavailing and impractical, would not produce any public advantage, and it is in the County’s and public’s best interest to work with the existing contractor on the project rather than competitively bid the project changes. See Graydon v. Pasadena, 104 Cal. App. 3d 631 (1980).
1. The change order includes new superstructure work, that modifies and is integrated into the original scope that the existing contractor was already mobilized and contracted to perform. The change order includes modifications to what the existing contractor was already constructing, such that it could not be bifurcated and independently performed in conjunction with what that contractor would still be performing. If the change order scope were to be awarded to a separate contractor, then two contractors would be performing essentially the same work at the same time. Having multiple contractors working on the same project gives rise to coordination and management difficulties that are likely to increase the ultimate cost of the project and delay its completion, along with complicating the lines of responsibility for construction delivery and quality.
2. The existing contractor was familiar with the challenges posed by the differing site conditions. Awareness of these site conditions and involvement with the redesigned solutions means that the negotiated price can be relied on to account for all the work needed, with low risk of future change orders due to claims such as unknown conditions or contractor lack of due diligence.
3. Because the Project involves work on the bridge structure, there are significant mobilization costs for delivering equipment, materials, and other needed items to the job site. The existing contractor has already incurred these mobilization costs to be in position to perform the change order work, so those are costs that for most part would not have to be re-incurred and again paid by the County. Because any new contractor would have their own new mobilization costs, those costs would likely be included in any new bid, which makes it very unlikely that a new bid amount would be less than the negotiated change order amount.
4. In general, bids for work to be performed during the standard construction season are more competitive (i.e., better priced) when issued during the winter. SPI’s experience and general procurement understanding is that bids issued during the construction season typically have lower participation and higher prices, since most contractors are already underway with existing bids and projects. Any bid for the change order scope would have been unlikely to come in at an amount less expensive than the existing contractor’s quote.
By taking the proposed action, the Board is asked to make the following findings, based on the facts set forth above: (1) All of the above statements are true and correct; (2) Competitive bidding of the change order work would not produce an advantage to the County, but would instead increase the cost of the Project, cause delays, and cause avoidable risks to Project management, delivery, quality, and responsibility; and (3) Competitive bidding of the change order work would be undesirable and impractical, and a waiver of competitive bidding is appropriate in this case.
Funding for the construction project is 88.53% Federal Highways Administration (FHWA) funds administered by Caltrans. SPI has conferred with Caltrans during the project, received assurance the costs are reimbursable and has submitted a request for reimbursement for these contract change orders.
Strategic Plan:
This item directly supports the County’s Five-year Strategic Plan and is aligned with the following pillar, goal, and objective.
Pillar: Resilient Infrastructure
Goal: Goal 3: Continue to invest in critical road, bridge, bicycle, and pedestrian infrastructure.
Objective: Objective 1: Continue to maintain road segments, including designated turnouts where feasible, increase efforts on vegetation removal and drainage features, and improve pavement conditions in neighborhoods.
Racial Equity:
Was this item identified as an opportunity to apply the Racial Equity Toolkit?
No
Prior Board Actions:
3/24/26: Board authorized SPI Director to execute construction contract change order for dewatering changes in the amount of $665,500 and increased the construction contract by $3,000,000.
12/16/2025: Board authorized SPI Director to execute construction contract change order for differing site conditions and acceleration in an amount up to $2,300,000.
2/06/2024: Board awarded project construction contract to Ghilotti Construction Company, Inc.
12/07/2021: Board approved Third Amendment to the design contract with Dewberry Engineers, Inc.
5/15/2020: Board adopted an Addendum to the Mitigated Negative Declaration
7/10/2018: Board approved Second Amendment to the design contract with Drake Haglan and Associates, Inc.
5/24/2016: Board approved First Amendment to the design contract with Drake Haglan and Associates, Inc.
11/24/2014: Board adopted a Mitigated Negative Declaration and Mitigation Monitoring Program and approved the Project
9/24/2013: Board approved design contract with Drake Haglan and Associates, Inc.
Fiscal Summary
|
Expenditures |
FY25-26 Adopted |
FY26-27 Projected |
FY27-28 Projected |
|
Budgeted Expenses |
$989,705 |
$9,660,121 |
|
|
Additional Appropriation Requested |
|
|
|
|
Total Expenditures |
$989,705 |
$9,660,121 |
|
|
Funding Sources |
|
|
|
|
General Fund/WA GF |
|
|
|
|
State/Federal |
$989,705 |
$9,660,121 |
|
|
Fees/Other |
|
|
|
|
Use of Fund Balance |
|
|
|
|
General Fund Contingencies |
|
|
|
|
Total Sources |
$989,705 |
$9,660,121 |
|
Narrative Explanation of Fiscal Impacts:
As of March 2026, $15,582,257 of work had been performed on this contract. If the new, not to exceed contract amount of $26,232,083 is approved by the Board the remaining balance of $10,649,826 will be expended in calendar year 2026. Appropriations for expected contract costs in FY 2025-26 are available in the Roads Capital (11051-34010103) Adopted Budget and appropriations for FY2026-27 planned expenditures will be included in the FY 2026-27 Roads Capital Recommended Budget.
The project is eligible for 88.53% reimbursement through the Federal Highway Administration (FHWA). SPI has applied for reimbursement of these expenditures, but the application has not yet been approved. In the event the application is denied, the Department would need to return to the Board to explore funding options for this work outside of traditional Roads funding sources (HUTA and/or SB1) including contributions from the General Fund.
Narrative Explanation of Staffing Impacts (If Required):
None
Attachments:
None.
Related Items “On File” with the Clerk of the Board:
None.