San Diego Freeway (I-405), SR 22 to SR 73 Widening Design-Build

Location Orange County, California

Owner Orange County Transportation Authority, Caltrans

Client OC 405 Partners

  • Design-Build Delivery
  • Design Management
  • Accelerated Schedule
  • Interstate Design
  • Interchange Design
  • Structural Design
  • Bridge Replacement
  • Maintenance-of-Traffic (MOT) Plan Development
  • High Occupancy Vehicle (HOV) Facility Planning/Design
  • Retaining Wall Design
  • Quality Control and Assurance

Orange County Transportation Authority’s (OCTA) $1.9 billion program widened 16 miles of the San Diego Freeway (I-405), from SR 73 to the I-605 interchange. The design-build included adding one general-purpose lane in each direction, adjusting freeway entrance and exit ramps, and replacing/modifying about 34 bridges.

To manage high traffic, the project utilized existing infrastructure for 405 Express Lanes, incorporating carpool lanes and connectors (opened in 2014) to reduce costs and project impacts. These lanes featured an additional toll lane in each direction for single occupant vehicles.

To meet milestones, the project team collaborated with the State of California’s Department of Transportation (Caltrans) using an over-the-shoulder review approach, expediting the process. Lochner formed an internal team for design, understanding design-build delivery and Caltrans District 12 standards.

Pacific Infrastructure 405 Designers, a joint venture of Lochner, Moffatt & Nichol, and Arup, led design efforts. Lochner managed design for two sub-segments, including SR 73 Junction and interchanges at Fairview, Harbor, and Euclid, plus 10 bridges, retaining walls, earthwork, drainage, pavement widening, barrier, and roadway finishes.

A comprehensive environmental management plan, developed with OCTA, addressed commitments, compliance with laws, regulations, and environmental goals.

The construction staging and maintenance of traffic (MOT) divided the project into three segments. The team worked concurrently in each segment, using a Transportation Management Plan (TMP) for safety. The TMP was customized based on input from local agencies along the corridor.

Project documentation, including plans, reports, and schedules, was prepared in ProjectWise. Lochner managed ProjectWise for the entire design-build team.

Quality management was crucial due to the project’s scale and complexity. The design management team implemented a Quality Management Plan (QMP) for a specific design, review, and approval process aligning with project complexities and governing agencies’ standards.

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