Sand Canyon Grade Separation

Irvine, California

Michael Baker provided design services for the Sand Canyon Avenue undercrossing at the Southern California Regional Rail Authority, Orange County Transportation Authority and Metrolink grade separation. Sand Canyon Avenue is a major east/west arterial highway link for the city of Irvine. The goal of the project was to realign Sand Canyon Avenue to the northwest and lower the roadway under the Metrolink Railroad, with which it intersects.

The grade separation required raising the existing track elevations 1.5 feet to allow roadway clearance. The project consisted of a two-span steel and concrete structure, which included a steel deck and steel plate girder bridge superstructure with two sacrificial exterior concrete girders, abutments, wing walls, temporary shoring, temporary double-track shoofly alignment southwest of the new bridge structure and elimination of the existing at-grade crossing.

Our team was responsible for roadway and rail realignment, structures design, pump station design, railroad permitting and coordination, railroad shoofly design, drainage design, utility relocation coordination, survey/right-of-way engineering, community outreach, landscape/irrigation, identification of funding, geotechnical engineering services and Caltrans encroachment permit for work within their right-of-way.

The difficulty in the design of this grade separation was the complexity of the stage construction. With short traveling distances between Sand Canyon and the LOSSAN Rail corridor and I-5, it became challenging to maintain access to the Old Town business district during construction to lower the roadway. To accomplish this feat, a multi-stage construction approach was developed: combining dual shoo-fly construction, temporary shoring, detour access routes and two phased week-end closures to facilitate rail mainline connection. Temporary water and oil line facilities were constructed to mitigate construction of the rail shoo-fly system and utility relocation corridors were developed to facilitate utility construction in advance of the grade separation work.


“As a result of this project, traffic on Sand Canyon Avenue is separated from the rail crossing, eliminating delays and creating a safer travel route for motorists, cyclists and pedestrians.”

Steve H.
Southern California Transportation Practice Lead

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