Structural Engineering Challenges: Innovative Retrofit Protects Television Anchors from Seismic Events

A team of structural engineers and architects faced multiple challenges when modernizing and retrofitting buildings that once served as the studios for Warner Brothers. How did the team minimize the risk of harm to the anchors of KTLA while meeting the standards set by the City of Los Angeles for historical and cultural landmarks?

Warner Brothers Studios in Hollywood, California circa 1928. Image via Wikimedia Commons

When the anchors of KTLA, which went on the air in 1947, became the subject of several parody videos and memes when an earthquake rocked the station in 2014, one wonders if safety was the only concern when their new studio was in the planning stages.

See the original news broadcast showing the reactions of the anchor team to the shaking caused by the 2014 earthquake by watching this video.

The Project

The San Andreas fault, which runs through the Coachella Valley southeast of Los Angeles, makes LA vulnerable to major earthquakes. Image courtesy of Matthew Field.

KTLA contracted with the award-winning structural engineering firm Structural Focus and the architects at Bastien and Associates, Inc. to make major upgrades, including significant improvements to provide protection during seismic events to Stage 6 at Sunset-Bronson Studios, which was the former Warner Brothers Studios location. Since two buildings that house Stage 6 date back to 1928, the City of Los Angeles considers the structures to be Historic and Cultural Landmarks. This designation provides significant protections for the buildings. In addition, the need for retrofitting to meet the standards for voluntary seismic strengthening set forth in the 2010 California Historical Building Code (CHBC) compounded the challenges faced by the architects and engineers working on this project. Given the projections for a major earthquake to hit the Los Angeles area, the project owners wanted the most robust seismic protections possible.  

While revised Los Angeles building codes have reduced the structural damage to buildings caused by seismic events, LA’s roads and bridges remain vulnerable to damage caused by earthquakes.

Additional Challenges

Street view of KTLA’s studios circa 2007. Image via Google Street View  and Wikimedia Commons .   

The architects and structural engineers working on this project faced two additional hurdles to cross to make it a success:

• Transform the existing historic structures into two “box in box” studios. The project required this design to minimize the acoustic bleed into the news studio from adjacent offices.
• Complete the seismic protection upgrades and the modernization of the studios and offices spaces while staying within the client’s budget.

Engineering Solutions

In an October 16, 2017 post on the Civil and Structural Engineer website, the founder of Structural Focus, David W. Cocke, S.E., F.SEI, F.ASCE, and the project engineer for the KTLA project, Melineh Zomorrodian, S.E., describe how their team overcame the challenges associated with retrofitting Studio 6.

Some of the solutions they devised include:

• In the studio, they used cold formed ceilings and braced panels, supported by steel beams and columns, to limit the lateral load.
• Light gauge steel saddle tracks provided vertical support and limited the gravity load on the historic wood floors.
• A small HSS tube cast on top of each individual pile with the cavity filled with cement served a part of the system that resists forces, such as those from seismic events, that may over turn the structures.

To learn more about this project, read their post.     

What is your opinion about the solutions to the challenges posed by this project? Have you used similar strategies in your work?