The San Diego River Bridge Double Track (SDRDT) project is located on the main line of the Los Angeles‐San Diego‐San Luis Obispo (LOSSAN) Corridor in San Diego, the second busiest intercity passenger rail corridor in the nation. The purpose of the SDRDT project is to construct a one-mile segment of second main track to connect existing double track segments at each end of the project limits. The centerpiece is an approximately 920-foot-long new double track bridge that will replace an existing segment.
The SDRDT project will be constructed at the same time, within the same footprint, and is anticipated to have combined CMGC delivery with the Mid-Coast Corridor Transit Project, a proposed double track segment of LRT adjacent to the SDRDT. Design, permitting, and construction schedule compatibility between the projects are critical. Site conditions at the bridge crossing present several technical challenges. Seismic hazard is significant, and the site is underlain with alluvium susceptible to liquefaction spreading to a depth of 85 feet and associated lateral spreading and post-earthquake settlement.
The preferred alignment and structure were selected through an evaluative criteria approach. Twin steel plate through girder bridges were chosen to minimize foundation costs and construction time. Substructure seismic and geotechnical hazards will be overcome with large diameter deep foundations and extensive ground improvement.
The Kleinfelder team has worked closely with the client to proactively mitigate schedule risk and ensure compatibility with the adjacent project. The project has completed environmental clearance and alternatives analysis, and design efforts are underway for construction in 2015.