The California Department of Transportation (Caltrans) is responsible for the maintenance and construction of over 45,000 miles of highways. The I-5/I-805 interchange was identified by Caltrans as a major problem area in the state.
The goal of this project is to reduce traffic congestion and improve safety through separation of truck traffic. To accomplish this, Caltrans decided that a separate bypass system from the junction of I-5 and I-805 to the Del Mar Heights Road Interchange needed to be constructed. This $180 million project includes the construction of a unique plantable geosynthetic reinforced retaining wall that transforms a simple slope into a vertical face that supports additional lanes of traffic.
To support these new lanes of traffic, Caltrans designed a geosynthetic wrapped retaining wall with a massive concrete basket system at the face. This two-part system allows an unplantable retaining wall constructed with layers of engineered fill and Mirafi high-strength woven geogrid (Miragrid) to be attached to a concrete facing system that protects the geosynthetic exposed at the face and holds loose plantable topsoil to facilitate vegetative growth. The end result is a massive, almost vertical retaining wall with heights in excess of 66 ft that will be completely vegetated.
The Mirafi geosynthetics supplied to the jobsite have performed well during and after construction.