Oct 2017


Sixth Street Viaduct Project: A Bridge of Firsts 

NEWESTNightRenderingViaduct.jpgThe design of the Sixth Street Viaduct is unlike anything seen before in Los Angeles and includes many engineering firsts.

For example, the 10 pairs of LED-lit arches use a concrete network tied design that will be built monolithically with Y-Bents. This is the first time in the world this has been done in a high seismic area.

We will be using sliding seismic isolation bearings mid-height in columns, which is also new in the U.S. The columns and abutments will use triple friction pendulum bearings for seismic base isolation, which will allow movement of 30” in any lateral direction.

The 9-degree cant of the concrete arches is also an industry first. 

The Bureau of Engineering is also using the EnvisionTM sustainable infrastructure rating system, another first for bridges in California. Envision encourages sustainability and resource efficiency and our goal is to achieve a Platinum rating, the highest awarded.

With all these groundbreaking features, the Sixth Street Viaduct Replacement Project is breaking ground in many ways here in Los Angeles. 

The Sixth Street Viaduct by the Numbers


  • More than 110,000 tons of rubble was removed during demolition
  • More than 6,000 truck loads were needed to remove rubble during demolition


  • The columns and abutments will use triple friction pendulum bearings for seismic base isolation, which will allow movement of 30” in any lateral direction


Arches will have a 9 degree cant and support the bridge deck with a cable network

The arches will be 10’ wide, with a typical arch span of 300’

There will be 3 different arch heights on new viaduct:

  • Over the railroads: 60’ – 2 pairs
  • Over US 101: 40’  - 1 pair
  • Over LA River: 30’ – 1 pair
  • Remaining arches: 30’ – 6 pairs 

The Viaduct

  • The length of the viaduct from Mateo Street  to just east of the 101 Freeway is approximately 3,500 feet
  • The viaduct will span 18 railroad tracks operated by 5 different railroad agencies
  • The width of the deck of the viaduct will be 100’, an increase of 40 feet
  • The new viaduct  will have 23 columns and 2 abutments
  • The piles will extend an average of 150’  underground, which is the equivalent to a 15-story building
  • Cables will have a diameter of 2 ¾ inches
  • 110,000 tons of concrete and 8,250 tons of steel will be needed to build the new viaduct 


  • Sidewalks on each side of the viaduct will vary from 8’ to 14’
  • 10‘ wide bike lanes will run along each side of the viaduct
  • Two bicycle/pedestrian ramp structures will provide access to ground level on each side of the river
  • The east ramp will be a 3.5 level helical structure connected by paths to both north and south sides of the viaduct
  • The helix will be 790’ long , 12’ wide, and 45’ tall. The  ramp from the south side of the structure is 640’ long
  • There will be a 510’ long west ramp from the  north side of the deck to the ground near Mateo Ave
  • There will be five stairs connecting the ground and the viaduct sidewalk, with climbing heights ranging between 25’ and 60’

Sixth Street PARC

  • There will be 12 acres of open and recreational space underneath the viaduct

 About the Project

 Stay Involved!

The Sixth Street Viaduct Replacement Project is a new, 3,500-foot long viaduct connecting Boyle Heights and the Arts District across the Los Angeles River. The original viaduct was built in 1932, but had significantly deteriorated due to "concrete cancer"; it was demolished in 2016. The new viaduct will have ten pairs of lit arches, bike lanes and wider sidewalks, along with stairway access and bike ramps connecting to 12 acres of recreational and open space under the bridge. The $482 million dollar project is the largest bridge project in the history of the city. The bridge is funded primarily through the Federal Highway Administration, with additional City support. The viaduct is expected to be completed by the end of 2020.

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And check out our website at www.sixthstreetviaduct.org

The Bureau of Engineering is the City's lead agency for the planning, design and construction management of the City's public buildings and its public infrastructure. Engineering is also responsible for managing permitting for all construction that takes place in the public right-of-way, as well as managing the City's state-of-the-art online mapping system, NavigateLA. Engineering is committed to designing and building environmentally-sustainable projects that include extensive community input. Engineering projects and services support the City's goals of creating a prosperous, livable and safe city for all residents and businesses.