An arch on the Sixth Street Viaduct Replacement Project, which began in 2016.

An arch on the Sixth Street Viaduct Replacement Project, which began in 2016.

It may be the largest construction project in Los Angeles history, but until recently, construction work related to the Sixth Street Viaduct replacement bridge had mainly been a local affair, rarely intruding on Angelenos’ larger consciousness.

But that changed around Halloween as a key segment of the 101 freeway through downtown was shut down for much of two recent weekends. The shutdown was to allow for the removal of falsework under the emerging bridge.


The Sixth Street Viaduct was originally opened in 1932 as a connection between the Arts District on the west side of the Los Angeles River and the historic neighborhood of Boyle Heights on the east side. The original bridge spanned nearly 3,500 feet across the river and was often used to represent Los Angeles’ grittier side in movies, music videos and TV shows, including for riverbed car chases.

 
But time literally ate away at the bridge as a rare chemical reaction in the concrete caused deterioration in the bridge structure. Because the bridge also needed to be seismically upgraded, the city’s Bureau of Engineering set to work creating a replacement.

 
The main unique feature from the design team for the new bridge — consisting of Kansas City, Mo.-based HNTB Corp. and Los Feliz-based Michael Maltzan Architecture Inc. — was a series of 10 sweeping arches on each side of the bridge, creating a nighttime effect called the “ribbon of light.”


Construction began in 2016 with the demolition of the old bridge.

 
That was a different strategy than was taking place simultaneously with another huge bridge project in L.A. County: the Gerald Desmond Bridge Replacement Project near the Port of Long Beach. On that project, the old bridge remained fully functional through construction and has yet to be demolished.


With the old Sixth Street Viaduct demolished, the construction team — led by a joint venture of Skanska USA Inc., a unit of Stockholm, Sweden-based Skanska, and Stacy and Witbeck Inc. of Alameda — set to work on its replacement. According to Mary Nemick, a spokeswoman for the Los Angeles Bureau of Engineering, which is overseeing the project, construction work is now nearly 80% complete.


She said the project is on track for the bridge to be completed and open next summer.

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