SR-22/I-405/I-605 West County Connector – Western Segment
This project was a continuation of the previously awarded SR-22/I-405 West County Connector – Eastern Segment Project. Like the previous project, this five-mile-long project created a more seamless transition—building direct connector ramps from the I-405 high-occupancy vehicle (HOV) lanes to I-605 and State Route 22 into Long Beach. Atkinson widened the outside lanes of I-405 to accommodate the additional HOV lanes in each direction within the median, constructed new I-405/I-605 HOV direct connector ramps, and reconstructed four bridge structures. These bridges include the Seal Beach Boulevard bridge (crossing over I-405), the eastbound SR-22 to the northbound I-405 connector, the eastbound SR-22 to northbound I-605 connector, and the northbound I-405 to the westbound SR-22 connector.
The I-405/I-605 HOV direct connector bridge measures 2,902 feet in length and sits 45 feet above I-405—which carries 415,000 cars daily. The HOV connector was constructed in the median of the freeway and required 26-foot-high retaining walls. Traditional cantilever retaining walls could not be used due to their construction footprint, and mechanically stabilized earth (MSE) walls were prohibited due to poor soil conditions. Therefore, the designer used an innovative approach to incorporate lightweight fill and precast panels for the structure approach.
Atkinson used its self-perform capabilities to install 20,000 LF of drainage, 42,000 cubic yards of bridge concrete, 2,200 cubic yards of wall concrete, 40,000 cubic yards of concrete paving, and 356,000 cubic yards of roadway excavation.