Webinar - Institute for Sustainable Infrastructure

Learning from the Sixth Street Viaduct Project including the Viaduct Seismic Improvement and Park, Arts, River and Connectivity Improvements (PARC)


Moderator: Jim Grant, HNTB

Presenter: Michael Jones, HNTB

ENV SP Credential Maintenance hours: 1 Elective hour

Qualification Credentials: RCEP PDH

The 3,500–foot long 6th Street Viaduct is a transformative landmark in Los Angeles constructed in 1932. Concrete elements of the original viaduct cracked and deteriorated over the next 75 years as a result of an internal Alkali Silica Reaction (ASR) caused by the reactive aggregate used in the concrete. Because of this ongoing and irreversible chemical action, it was determined that replacement was necessary during seismic vulnerability studies that determined the structure was susceptible to failure during major seismic activity. Additional geometric design, safety and functional deficiencies resulted in the decision to demolish and replace the bridge with a new 6th Street Viaduct. Presenters will discuss how the project met the following goals:

  • Preserve 6th Street as a viable east-west link between Boyle Heights and Downtown Los Angeles
  • Reduce vulnerability of the 6th Street Viaduct in major earthquake events
  • Integrate the viaduct with the surrounding community
  • Increase the role and functions of this urban viaduct
  • Enhance and encourage multi-modalism transporation
  • Resolve design deficiencies of the 6th Street Viaduct

Learning Objectives

  • Review the Envision Platinum 6th Street Viaduct Project
  • Identify the purpose of the project and its enhanced community benefits
  • List the project’s wide-ranging sustainability achievements