The Crenshaw/LAX Transit Corridor Project is part of the largest transit expansion program in the United States with five Los Angeles County Metropolitan Transportation Authority (Metro) rail lines simultaneously under construction, and additional stages planned for the future. SAGE is providing Support of Excavation (SOE) engineering design, as well as Independent Design Check services to the Walsh Shea Corridor Constructors Joint Venture (WSCC) for the Crenshaw/LAX Transit Corridor Project.
SAGE has been retained to design temporary excavation support systems up to 38 feet deep and 7,000-feet-long for the cut-and-cover construction of Underground Guideways for subterranean rail stations being installed as part of Metro’s transit corridor expansion. In order to minimize disruption to public traffic, the SOE system has been designed with integral traffic decking spanning the top of select portions of Crenshaw Blvd., conveying public traffic over the top of the excavation and supporting existing operational utilities in place.
The Crenshaw/LAX SOE design comprises steel soldier piles braced with internal pipe struts. The SOE system incorporates both cantilevered and full-width steel beams supporting concrete traffic decking to allow excavation and construction of the guideways while maintaining traffic on Crenshaw Blvd. Soil between the soldier piles is retained by timber lagging.
SAGE Engineers has worked closely with WSCC throughout design and construction of the SOE systems to optimize design details such as variable strut sizes, member shapes and configurations, and alternative layouts to accommodate WSCC’s use of specialized construction equipment and staging requirements. In addition, SAGE has coordinated extensively with other project stakeholders, including Metro, LA Bureau of Engineering, ARUP (the project geotechnical engineer of record), and Aldea (designer for stations) to ensure completion of the project as efficiently as practicable, while still meeting stringent Metro design criteria.