The San Bernardino County Transportation Authority (SBCTA), in partnership with the City of Chino and Caltrans District 8, is undertaking a significant project to improve traffic flow and accessibility along Central Avenue and SR 60. One crucial aspect of this endeavor involves widening the Central Avenue interchange at the SR 60 bridge.

To accommodate the increasing number of commuters, the interchange will be expanded to include three through-lanes and double left-turn lanes in both directions. Additionally, the existing on-ramps to SR 60 will be widened from one lane to two through lanes, along with the addition of a carpool lane.

During the road widening process, the presence of an existing box culvert posed a challenge when it came to implementing a new retaining wall. To address this issue and ensure the structural integrity of the project, a careful decision was made. Class III cellular concrete was chosen as the backfill material for the retaining wall. This choice effectively reduces the load on the box culvert, promoting its longevity and performance.

The process involved adding the cellular concrete in successive 2-foot lifts, with a total fill depth of approximately 6 feet. This meticulous approach ensures that the project meets the necessary safety and stability requirements.