I-5/County Road 102 Interchange Improvements

This Caltrans Local Assistance and Federal Aid project included widening of the existing overcrossing, construction of new ramps, and widening of County Road 102. Blackburn completed Caltrans-reviewed Foundation, Geotechnical Design, and Materials Reports for project design. During construction, Blackburn provided quality assurance field and laboratory testing of hot mix asphalt, aggregate base, structural concrete, and embankment fill compaction. During pile driving, Blackburn continually monitored settlement data during surcharge loading of the embankments to release them for bridge abutment construction as soon as possible.

When the contractor encountered unstable subgrade during winter construction, Blackburn recommended using of geo grid to stabilize soft subgrade to keep the project on schedule.

To mitigate challenges related to heavy traffic loads at the bottom of bridge approaches, Blackburn reviewed submittals and provided guidance using Caltrans Standard Special Provisions for the use of high stability hot mix asphalt type C.