Project: Sixth Street Viaduct
City of Los Angeles Bureau of Engineering and HNTB Corporation
A bridge that has emotional connections with public
What do you do when you are assigned a design and construction project involving the replacement of a local landmark? It becomes paramount to communicate to the public that the piece of infrastructure they are getting as a replacement not only will be equal to the existing landmark, but also will go beyond in its ability to serve the public with greater safety and as a recreational amenity. The 3rd place winner of the 2015 Excellence in Infrastructure competition experienced this and here is their story.
Spanning the Los Angeles River, the Sixth Street Viaduct is one of America’s most iconic bridges, having appeared in more than two dozen films. A chemical reaction taking place in the cement used to construct the bridge makes it vulnerable to earthquakes, and therefore it must be replaced. The City of Los Angeles decided the much-loved structure needed a worthy—and equally striking—replacement. The new bridge, designed by structural engineer, Ted Zoli, and architect, Michael Maltzan, will feature multiple arches and a distinctive lighting system that maximizes light coverage and minimizes glare and shadows. The city tapped HNTB to provide the executive architectural and engineering services required to realize the team’s vision. Learn more in this New 6th Street Viaduct is a bridge to a different future in the LA Times.
The Six Street Viaduct will be the first bridge in California to rely on continuous un-braced tied network arches as a structural system. Each arch will be supported by columns set on their own isolation bearings, which will greatly enhance seismic performance. HNTB realized that the complexity of the bridge would require sophisticated analysis and simulation along with accurate visualization. Given the demands of the project, the design team chose to employ a model-based workflow and a Building Information Modeling (BIM) process from the earliest stages of the project. With the initial models developed in Autodesk Revit, the team decided to enhance its ability to model the geometry of the bridge with Autodesk Dynamo Studio. Dynamo helped the team control and understand the parameters of the bridge. Throughout the process, the team was able to analyze the complex forms and unique shapes called for in the design for aesthetic effect, structural loads, wind loads, drainage, and more.
HNTB Corporation is an employee-owned infrastructure firm serving public and private owners and contractors. With more than a century of service in the United States, HNTB understands the life cycle of infrastructure and addresses clients’ most complex technical, financial and operational challenges. Professionals nationwide deliver a full range of infrastructure-related services, including award-winning planning, design, program management and construction management. For more information, visit www.hntb.com.