State Route 22 Freeway
OCTA and Caltrans proposed to construct improvements for the SR-22 freeway in Orange County consisting of widening the freeway and construction of HOV lanes.DEG performed laboratory testing on the samples recovered from the borings and developed 33 Post Advanced Planning Study Geotechnical Data Reports for 33 bridges along the alignment. These reports included compilation of existing and new boring and laboratory data, foundation conditions, assessment of liquefaction potential and discussion of various foundation types. Delta’s responsibilities also included review of the design build contractor’s submittals, and QA/QC testing during the construction. All work was performed under a formal QA/QC program in accordance with the ISO 9000 and was audited by Parsons Transportation, the team leader. Key Geotechnical Issues: Coordination with multiple agencies, traffic control, night work, restrictive work hours, and working on an operating freeway with narrow shoulders Moderate seismic accelerations and shallow groundwater • High liquefaction potential along a significant portion of the alignment Bridges over Santa Ana River and Santiago Creek with shallow groundwater and difficult pile driving conditions due to presence of cobbles Working with Caltrans in-house geotechnical personnel to clarify foundation design criteria where liquefaction and down drag are present.