PacRim is part of the HNTB team in the structural design of the River Gateway Structure under the main 6th Street Viaduct. The structure comprises of 3 railroad bridges that create a portal to connect central downtown Los Angeles to the Los Angeles River.
Constructed in 1932, the Sixth Street Viaduct (also known as the Sixth Street Bridge) is an important engineering landmark in the City of Los Angeles. Located in a highly urbanized area just east of downtown Los Angeles, the bridge is a critical transportation link between LA Arts District and Boyle Heights.
It is one of a set of fourteen historic Los Angeles River crossing structures and is the longest of these structures. A 1986 Caltrans bridge survey found it to be eligible for inclusion in the National Register of Historic Places.
The Sixth Street Viaduct (designated as City of Los Angeles [City] Bridge No. 53C-1880 and California Department of Transportation [Caltrans] Bridge No. 53-0595 [portion of viaduct over Hollywood Freeway or US 101]) has an overall length of 3,500 ft., and extends east-west across the Los Angeles River, multiple railroad tracks, US 101, and several local streets. It has a 46 foot wide, four-lane roadway with 11-foot eastbound and westbound inside traffic lanes and 12-feet outside lanes with no shoulders. There are sidewalks of varying widths on both sides.