BON AIR BRIDGE REPLACEMENT

Client

City of Larkspur DPW​

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Location

Larkspur, CA​

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Status

On Going (Completion - 2021)

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Construction Cost

$28 Million (Estimated)

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Stakeholders

Caltrans, City of Larkspur, PG&E, USDFW

Coastal Commission

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Description

The replacement bridge features a reduced number of bridge supports for better creek access and reduced flooding risk, dedicated bike lanes, and protected multi‐use paths for improved bike and pedestrian safety. The project involves the construction of a 5‐span PC‐PS box girder bridge and large diameter CIDH piling, partial removal of the existing 10‐span steel girder bridge. In addition to the bridge construction, significant project elements included:

• Complex Staging and Traffic Control which includes construction of two (2) temporary trestles

• AT&T Early Utility Relocation Contract

• 48‐Inch Diameter Storm Drain Relocation

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Services

PreScience provides construction management and inspection services that include constructability review, construction project advertising, bid analysis, and award, construction oversight and inspection, Gamma‐Gamma logging, contractor interface and contract administration, office engineering, public outreach support, quality assurance, and safety and biological monitoring.

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Challenges

The PreScience Construction Management Team was instrumental in partnering with the contractor and designer to execute value engineering to redesign the bridge’s superstructure from PCC trapezoidal box girders to wide flange girders. This change resulted in considerable cost and time savings to the City and led the path to resolve a substantial potential claim related to a differing site condition.