Crenshaw/LAX Transit Corridor Project

Gannett Fleming provided temporary support of excavation (SOE) engineering design and independent design review services to the Walsh/Shea Corridor Constructors Joint Venture (WSCC) for the project.

Our team designed temporary excavation support systems up to 38 feet deep and 7,000 feet long for the cut-and-cover construction of guideways for new underground rail stations being installed as part of Metro’s transit corridor expansion. The SOE system was designed with integral traffic decking spanning the top of select portions of Crenshaw Boulevard, conveying public traffic over the excavation and supporting existing operational utilities in place.

The excavation support system featured steel soldier piles internally braced with pipe struts across a 45- to 55-foot-wide trench. The system incorporated both cantilevered and full-width steel beams supporting concrete decking to allow excavation and construction of the guideways while maintaining traffic on Crenshaw Boulevard. The soil between the soldier piles was retained by timber lagging. Pipe struts were preloaded with hydraulic rams and then welded in place to minimize shoring deflections during excavation.

We worked closely with WSCC to optimize and customize design details. Variable strut sizes, alternative member shapes and configurations, and varying layouts were considered to accommodate the use of specialized construction equipment and procedures and complex staging requirements. Additionally, we coordinated extensively with Metro and the Los Angeles Bureau of Engineering, as well as the project’s geotechnical engineering and underground guideway design teams, to ensure successful project completion while meeting stringent Metro design criteria.

• Steel soldier piles and timber lagging provide safe, time-tested excavation support.
• Preloaded internal pipe strut configuration supports excavation walls with minimum deflections and allows for the use of specialized guideway construction equipment with high-clearance requirements.
• Integral concrete decking and a maintenance of traffic plan minimized travel disruptions in this key city artery.

• New access to opportunity for numerous South Los Angeles communities, including Crenshaw Corridor, Hyde Park, Leimert Park, Fairview Heights, Inglewood, and Westchester.
• Easier access to medical facilities, workplaces, and commerce centers throughout Los Angeles.
• Key connection of K Line of Downtown Los Angeles with LAX coming in 2024.