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| Nabih Youssef of Nabih Youssef Associates used a cutting-edge engineering approach to make the new hotel/condo tower at L.A. Live seismically sound. The building opens Feb. 15. Photo by Gary Leonard. |
Structural Engineer Nabih Youssef Discusses the 54-Story Tower’s Ability to Withstand an Earthquake
by Anna Scott
DOWNTOWN LOS ANGELES - It might not be obvious to the naked eye, but the 54-story J.W. Marriott/Ritz-Carlton hotel-condominium tower at L.A. Live is unlike any other high-rise in the city.
That stems from the work of structural engineer Nabih Youssef, head of the 20-year-old, Downtown-based firm Nabih Youssef Associates. NYA, known for using cutting-edge technology in the service of seismic safety, took that track record to a new level by employing a never-before-tried approach to the project that includes 1,001 hotel rooms and 264 condos.
Youssef, whose firm has also worked on structures including Dodger Stadium, the new LAPD headquarters, City Hall and the Cathedral of Our Lady of the Angels, spoke with Los Angeles Downtown News about his innovative approach to his latest project.
Los Angeles Downtown News: How did you initially conceive of your approach to the Marriott/Ritz-Carlton tower?
Nabih Youssef: In 2007 we were asked to generate what I would call a new concept for a high-rise hospitality tower. The traditional solution for a tower on the West Coast has been massive concrete shear walls. They’re three feet thick on average. When I looked at the elegance of the tower’s design, and the curves, the lightness and smooth form inspired me to think of a material that has the ability to do these formations while remaining flexible.
Q: What do shear walls do?
A: In your home, you have plywood shear walls so the house does not rock or pancake [in an earthquake]. When you get into commercial buildings, most have these massive concrete walls reinforced to provide resistance against the force of an earthquake. It prevents the rocking of the floors, which leads to failure.
Q: What did you do differently with the walls at the L.A. Live tower?
A: In lieu of these massive concrete shear walls, which are very rigid, we proposed very thin — a quarter to three-eighths of an inch — steel plates. They have the ability to deform and yield, and by doing so they dissipate the energy of the earthquake rather than rupturing. With concrete you see cracking.
Q: What level earthquake do you anticipate the building could withstand?
A: The ever-increasing seismic hazard of the L.A. basin was one area of challenge. The Elysian Fault structure… has a potential magnitude of a 7 type earthquake right under the L.A. basin, and it has higher modes of vibration effects when you have such a slender structure.
Q: So what would happen to the structure if there were a massive earthquake tomorrow?
A: It would basically roll back and forth, like any well-designed, high-performance, high-rise building. It would roll gently back and forth, and by doing so dissipate the energy of the earthquake.
Q: What other challenges did you face in bringing your idea to fruition?
A: In any commercial development, when you talk about the first of its kind, there is a lot of apprehension and concern. Just procuring the high-performance steel on the world market was a challenge. Also, being the first of its kind, it was beyond the current… state codes that L.A. city adopts, so we had to go to “performance based” engineering, which requires us to set up a panel of experts to review the design. We had a panel of four seismic experts.
Q: What were the benefits of engineering the project this way, aside from aesthetics?
A: Savings in cost, savings in schedule and additional square footage. The total building was three months ahead of schedule. The second big part is the efficiency of the floor plate. We had an increase of available square footage of about 7,000 square feet. With real estate value, every inch counts.
Contact Anna Scott at anna@downtownnews.com.
page 9, 02/08/2010
©Los Angeles Downtown News. Reprinting items retrieved from the archives are for personal use only. They may not be reproduced or retransmitted without permission of the Los Angeles Downtown News. If you would like to re-distribute anything from the Los Angeles Downtown News Archives, please call our permissions department at (213) 481-1448.
That stems from the work of structural engineer Nabih Youssef, head of the 20-year-old, Downtown-based firm Nabih Youssef Associates. NYA, known for using cutting-edge technology in the service of seismic safety, took that track record to a new level by employing a never-before-tried approach to the project that includes 1,001 hotel rooms and 264 condos.
Youssef, whose firm has also worked on structures including Dodger Stadium, the new LAPD headquarters, City Hall and the Cathedral of Our Lady of the Angels, spoke with Los Angeles Downtown News about his innovative approach to his latest project.
Los Angeles Downtown News: How did you initially conceive of your approach to the Marriott/Ritz-Carlton tower?
Nabih Youssef: In 2007 we were asked to generate what I would call a new concept for a high-rise hospitality tower. The traditional solution for a tower on the West Coast has been massive concrete shear walls. They’re three feet thick on average. When I looked at the elegance of the tower’s design, and the curves, the lightness and smooth form inspired me to think of a material that has the ability to do these formations while remaining flexible.
Q: What do shear walls do?
A: In your home, you have plywood shear walls so the house does not rock or pancake [in an earthquake]. When you get into commercial buildings, most have these massive concrete walls reinforced to provide resistance against the force of an earthquake. It prevents the rocking of the floors, which leads to failure.
Q: What did you do differently with the walls at the L.A. Live tower?
A: In lieu of these massive concrete shear walls, which are very rigid, we proposed very thin — a quarter to three-eighths of an inch — steel plates. They have the ability to deform and yield, and by doing so they dissipate the energy of the earthquake rather than rupturing. With concrete you see cracking.
Q: What level earthquake do you anticipate the building could withstand?
A: The ever-increasing seismic hazard of the L.A. basin was one area of challenge. The Elysian Fault structure… has a potential magnitude of a 7 type earthquake right under the L.A. basin, and it has higher modes of vibration effects when you have such a slender structure.
Q: So what would happen to the structure if there were a massive earthquake tomorrow?
A: It would basically roll back and forth, like any well-designed, high-performance, high-rise building. It would roll gently back and forth, and by doing so dissipate the energy of the earthquake.
Q: What other challenges did you face in bringing your idea to fruition?
A: In any commercial development, when you talk about the first of its kind, there is a lot of apprehension and concern. Just procuring the high-performance steel on the world market was a challenge. Also, being the first of its kind, it was beyond the current… state codes that L.A. city adopts, so we had to go to “performance based” engineering, which requires us to set up a panel of experts to review the design. We had a panel of four seismic experts.
Q: What were the benefits of engineering the project this way, aside from aesthetics?
A: Savings in cost, savings in schedule and additional square footage. The total building was three months ahead of schedule. The second big part is the efficiency of the floor plate. We had an increase of available square footage of about 7,000 square feet. With real estate value, every inch counts.
Contact Anna Scott at anna@downtownnews.com.
page 9, 02/08/2010
©Los Angeles Downtown News. Reprinting items retrieved from the archives are for personal use only. They may not be reproduced or retransmitted without permission of the Los Angeles Downtown News. If you would like to re-distribute anything from the Los Angeles Downtown News Archives, please call our permissions department at (213) 481-1448.
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Reader Comments
The following are comments from the readers. In no way do they represent the view of ladowntownnews.com.
Ted Trent wrote on Feb 6, 2010 1:53 AM:
" I like the Ritz, but I will be honest, I love me a good old fashion loft too. Personally, I prefer me a little piece of Biscuit Company, Eastern Columbia and Molino Street. My partner Drew would probably enjoy himself a nice piece of the Ritz over industrial living anyday. I look forward to meeting our new neighbors high up in the sky. I just hope that the Ritz, the Regal, the Staples, and the LA LIVE continue to embrace the community that has so graciously welcomed them. "
Michael Tagupa wrote on Feb 12, 2010 8:37 PM:
" This hotel will be another welcome addition to the growing South Park residentail & retail area. Now, this hotel will compliment the convention center which it sorely needs to bring in more convention sales. The hotel should have been built back in 1971, when the convention center was built, and when construction costs were much cheaper. I hope things will now change for the better. "
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Dave wrote on Feb 5, 2010 9:35 PM:
Q: What level earthquake do you anticipate the building could withstand? "