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SR 125/SR 94 New Freeway to Freeway Interchange

Dokken Engineering prepared the PS&E of a 4-level freeway-to-freeway interchange. The project is the largest consultant designed interchange in San Diego County. To ensure funding deadlines were met, Dokken Engineering accelerated the PS&E schedule. The project plans were approved in 31 months, nearly 5 months ahead of the original schedule. Dokken staff provided daily construction support for 3 years. Once the project was completed, Dokken's final estimate was proven to be within 4.8% of the contractor's estimate.

Preliminary Engineering
Preliminary Engineering was established roadway geometrics and profiles, determine the location of a major frontage road, and determine required right of way. The results of our preliminary engineering, completed concurrently during the PS&E, was to shift portions of the interchange to avoid acquiring a controversial business, reduce the cost of the proposed structures by over $6 million, and add access from Spring Street to southbound SR 125.

Bridge Design
Dokken designed 7 major bridges and 4 Mechanically Stabilized Embankment (MSE) retaining walls. The total length of the bridges is 9,900 feet with some of the columns exceed 100 feet in height. Special features of the bridges include 3 outrigger bent caps, and the use of site specific seismic criteria. High seismic loads from the nearby Rose Canyon Fault were handled with advanced dynamic analysis techniques and innovative seismic isolation column casings.

Drainage Design
Prior to the completion of the project, the intersection of Broadway and Sweetwater Road was often flooded during major storm events. As part of the interchange drainage design, a detention basin was designed to eliminate the recurring flooding. Dokken developed a system of storm-water diversion and retention facilities assuring that the existing facilities would not be continually flooded during major storms.