GUEST PRESENTERS:

ASCE invites Sacramento Section members to see a dynamic presentation by Sherri Berexa, Project Manager for Placer County, and John Quincy, Project Manager and President of Quincy Engineering, Inc. as they highlight design concerns and unique construction features for this major project.

TOPIC:  FORESTHILL BRIDGE SEISMIC RETROFIT AND UPGRADE 

The Auburn-Foresthill Bridge was built by the Bureau of Reclamation in 1973. The 2,428 ft. long bridge is comprised of three spans (639 ft. – 862 ft. – 639 ft.) and sits 730 ft. above the North Fork of the American River and would have spanned the reservoir created by the proposed, but never constructed Auburn Dam. As part of the Local Agency Seismic Retrofit Program, Placer County and the Quincy Engineering consultant team embarked on the seismic analysis and retrofit design of this bridge.

This project expanded upon the concepts and design methodologies that were developed during the retrofits of the California Toll Bridge Program. A strain based design criteria was developed for all the concrete and steel members of the bridge. The project specific design criteria may serve as the “next generation” for complex steel seismic retrofit projects. The time history model incorporated both material and geometric non-linearity components and was capable of capturing the global buckling of steel members and reporting member strains. The gusset plates were evaluated to ensure any ductile behavior was limited to the members themselves and not the connections. The project incorporated the use of large Buckling Restrained Braces (BRB) to improve the performance of the bridge during large seismic events. BRB’s are simple, low maintenance devices that dissipate energy and improve the seismic behavior of steel structures.

 In addition, the original paint system for the bridge has deteriorated and requires a new paint system in its place for corrosion protection and aesthetics.  Total construction cost is estimated to be over $70M. The project is currently out to bid, with construction anticipated to start in late 2010 or early 2011. 

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Marinated Flan Steak: Balsamic and Molasses Marinated Flank Steak with Sun-Dried Portabella Mushroom Demi-Glace; Includes Salad, Seasonal Vegetables, Rolls & Butter, Dessert, Starbucks Coffee, Hot & Iced Tea

*Veggie Selection Pending

CONTACT

Thor Larsen, Chapter President; E: thor.larsen@edcgov.us; C 916.806.9098