Sixth Street Viaduct


The Sixth Street Viaduct, also known as the Sixth Street Bridge, was a viaduct bridge that connected the Arts District in Downtown Los Angeles with the Boyle Heights neighborhood. It spanned the Los Angeles River, the Santa Ana Freeway, and the Golden State Freeway, as well as Metrolink and Union Pacific railroad tracks and several local streets. Built in 1932, the viaduct was composed of three independent structures: the reinforced concrete west segment, the central steel arch segment over the river, and the reinforced concrete east segment. In 1986, the Caltrans bridge survey found the Sixth Street Viaduct eligible for inclusion in the National Register of Historic Places.
Despite its historical status, the bridge was closed for demolition and replacement in January 2016 due to concerns over seismic instability.

Demolition and replacement

During the construction of the viaduct in the 1930s, an onsite plant was used to supply the concrete for construction. However, the quality of the concrete turned out to have a high alkali content and led to an alkali-silica reaction which created cracks in the concrete and sapped the strength of the structure. It is the only one of the historic LA River bridges to suffer from ASR.
Estimates stated that the viaduct had a 70% probability of collapse due to a major earthquake within 50 years. After initial demolition plans were delayed, the bridge was closed on January 27, 2016, and demolition began on February 5, 2016. It took nine months to demolish the existing bridge.
Prior to the demolition, Los Angeles mayor Eric Garcetti recorded the R&B song "101SlowJam", backed by musicians from the city's Roosevelt High School, and issued it via a video on his own YouTube channel. The public service announcement video advertised the closure of parts of the 101 Freeway to accommodate the demolition of the viaduct. An estimated 48,000 cubic yards of concrete, 1,245 tons of structural steel and 4,200 tons of rebar were hauled away as construction began on the replacement.
The new not yet completed bridge is designed by architect Michael Maltzan and the HNTB Design-Build team and contractors Skanska and Stacy and Witbeck. The new design has several green spaces built under and around it. Bridge construction has experienced several years long construction delays and multi-million dollar cost increases. The latest completion date is set for March 2022.

Cultural depictions

The bridge is a well-known local landmark, and has appeared in numerous films, television shows, music videos and video games since 1932.

Films