Foresthill Bridge Seismic Retrofit

Key Facts:

  • Type: Deck Truss
  • Length: 2,428 ft.
  • Width: 75'
  • Construction Cost: $58 million

Key Staff:

Project Manager: John Quincy, P.E.
Project Engineer: Mark Reno, P.E.


Placer County

Project Description

Quincy Engineering Inc. completed a seismic evaluation, developed alternative retrofit solutions and prepared the plans, specifications, and estimate (PS&E) for the Foresthill Bridge Seismic Retrofit project in Placer County.
The bridge is a 2,428 foot long truss bridge that rises over 700 feet above the American River canyon. It provides the primary link between the towns of Auburn and Foresthill, California. As part of the retrofit, the bridge is also being widened to maintain traffic while the retrofit measures are being constructed.

Services Performed:

  • Evaluate seismic vulnerability, structural yielding, and failure mechanisms
  • Develop alternative retrofit solutions
  • Final design modifications and bid documents to improve seismic performance

After an initial assessment, it was concluded that the structure has numerous deficiencies that could lead to collapse or other unfavorable behavior. During the development of the Retrofit Strategy, several measures were analyzed for their ability to improve the performance of the bridge and reduce the likelihood of collapse during a seismic event. Other tasks included completing of environmental documents for permitting, obtaining right of way and construction easements, and coordinating with utilities prior to construction.

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Our clients include:
  • Caltrans
  • ODOT
  • Federal Highway Administration
  • Central Federal Lands
  • Oregon’s OTIA III Bridge Program
  • ...and many cities and counties throughout California and Oregon.
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