Bridging the Gap: How Julie Allen ’92 Brought Los Angeles’ Sixth Street Viaduct to Life


On July 10, the rebuilt Sixth Street Bridge in Los Angeles opened to the public, establishing itself as a new landmark in the city landscape that connects the Downtown Arts District to East Los Angeles above the Los Angeles River.

As pedestrians, cyclists and skateboarders made their way along the bridge, taking in the sweeping views of the LA skyline, few likely knew that any of the people they were to thank for the new stretch of road was an engineer Bruin.

Julie Allen, who earned a bachelor’s degree in civil and environmental engineering in 1992, was the project manager for the Sixth Street Viaduct for seven years, working since 2015 as a senior civil engineer in the office of the Public Works Department of Los Angeles (LADPW). of Engineering to bring the $588 million bridge to life.

Before putting her skills to use creating a new crown jewel for the city, Allen was a young student with a passion for learning. Growing up in Modesto in California’s Central Valley, she spent her days on the debate team and in mock trial competitions and academic decathlons. She also developed a passion for technical drawing, also known as drawing, and for architecture.

When it came time to search for a college program that would combine his many passions, Allen chose civil engineering.

“I decided that civil engineering would be a great major to merge my interest in structures and my aptitude for mathematics, and that would still leave me the option of going to law school if I didn’t like engineering. “said Allen, who is now deputy director of the LADPW Office of Sanitation. “I found UCLA not only to be an outstanding engineering school, but also had a lot to offer outside of the classroom.”

At UCLA, Allen’s drive and ambition continued to grow. She completed two engineering internships while pursuing her undergraduate studies: one with the LA Department of Water and Power (LADWP) and the other with the LA County Health Districts.

After earning his bachelor’s degree, Allen began his career at LADWP in the Environmental and Governmental Affairs Department before joining the city’s Bureau of Engineering.

“It was extremely important that we created a new iconic landmark for residents because the bridge we were replacing was so loved by the community,” said Julie Allen.

The design of the bridge was approximately 35% complete when Allen began overseeing the complex logistics of financing, spending, obtaining agency approvals, and other technical and environmental considerations to ensure the bridge was structurally and environmentally sound.

The new bridge replaces the original Sixth Street Bridge built in 1932, which was an iconic landmark in its own right – with John Travolta drag racing underneath in the hit film ‘Grease’ and countless features in other films, music videos car music and commercials.

Over time, however, the bridge had slowly collapsed, making it extremely vulnerable in the event of an earthquake. The concrete for the bridge was mixed using an aggregate source from the Santa Barbara area, which was high in alkali, ultimately creating a chemical reaction that caused the concrete to crumble. The new bridge, however, is able to withstand a seismic event that occurs only once in a millennium, with a magnitude of around 7.8 or greater.

Each column of the bridge sits on a triple-friction pendulum bearing nearly 7 feet in diameter, and the viaduct is a continuous structure, with expansion joints appearing only at each end of the bridge. This means that, during an earthquake, the structure will move as a single unit while the ground below it shakes.

“While I hope the big one doesn’t hit Los Angeles, if you were on the Sixth Street Overpass it would be a very safe place,” Allen said.

The project required the collaboration of many accomplished engineers, including former Gary Lee Moore ’85 who holds a bachelor’s degree in mechanical engineering. As the city’s engineer, Moore provided executive oversight during the project’s 20-year development process, from initial design and environmental approvals to final completion.

For Allen, it was important to honor the cultural heritage of the original bridge and create a new place for Angelenos to enjoy their town.

Julie Allen at the Sixth Street Viaduct construction site in April 2021

“It was extremely important that we created a new iconic landmark for residents because the bridge we were replacing was so loved by the community,” she said. “Our goal is for the bridge to represent Los Angeles and for residents to be proud to be part of its history.”

Among the many features of the Sixth Street Bridge are some of Allen’s favorites. The iconic undulating arches can be lit in different colors to celebrate holidays and community events, and a helical ramp that allows Americans to access the Disability Act from the ground to the bridge deck and gives pedestrians a close-up view from under the deck and its beams.

Another unexpected element? Bat houses.

“Since there were bats living in the various openings of the original overpass, we had to install permanent bat houses on the girders and girders of the new bridge,” Allen said. “After the park is complete you can enter the LA River under the bridge and if you look up you can see the concrete bat houses set under the bridge.”

While at UCLA, Allen met her future husband, Ted, who was also studying civil engineering – marking the start of what would become a family of engineers, including a few Bruin engineers. Ted Allen was recently appointed city ​​engineer and executive director of the LA Bureau of Engineering by Mayor Eric Garcetti.

Their son, Noah, just graduated with a degree in computer engineering from UC Riverside while their daughter, Kyra, is a sophomore in aerospace engineering at UCLA.

“We’re so proud of them both,” Allen said. “In fact, an entire neighborhood may have heard my excited cry when Kyra found out she was admitted. Ted and I have both stayed connected to UCLA engineering in various ways, so it’s truly rewarding to be able to share this experience with our daughter.

Allen’s advice to the next generation of civil engineers is to explore as many areas of specialization as possible, because you never know what’s coming next in your career.

“We are so lucky that UCLA provides such a strong foundation in all areas of civil engineering, so even if you change courses mid-career like I did, you can always come back to your training to remember key skills and knowledge needed to be successful,” she said.

Sara Hubbard contributed to this story.


Comments are closed.