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02.16.2010
In Detail> JW Marriott and Ritz-Carlton
Gensler's tapering, glass-mosaic tower marks a milestone for L.A. Live
The tapering form of Gensler's 55-story tower provides larger spaces for the Ritz suites, which are located above Marriott's hotel rooms.
Ryan Gobuty



The tower lends a dose of dynamism to the L.A. Live entertainment complex (top). the  L-shaped structure utilizes a steel-plate shear wall system to maximize usable space and views (above). 

All images: ryan gobuty
 
 

Despite the epic meltdown that’s dashed projects across California, L.A. Live, the mixed-use downtown mega-complex, is actually finished. And hovering above everything, the 55-story JW Marriott Hotel and Ritz-Carlton Hotel and Residences at its eastern end opened yesterday (more or less—the Ritz portion formally opens on March 15). Designed by Gensler, the $1 billion project includes 877 Marriott guest rooms, 124 Ritz hotel rooms, 224 condos, and an 80,000-square-foot conference center.

While the 2 million-square-foot building’s irregular, tapering shape is impossible to miss from anywhere within eyeshot of downtown, what’s perhaps most interesting about this project are the design and construction strategies that helped create the form, streamline the process, and fit a monster of a program neatly into one complex building.

The tower’s bulging profile was brought about by the need to make the Ritz-Carlton suites and condos larger than the JW Marriott rooms below. The latter are all 10 feet tall and 30 feet long, while the Ritz-Carlton rooms and residences above them vary from 10 feet 6 inches to 14 feet tall and 38 to 42 feet long. The move was made possible through curved steel columns installed near the top of the building, making it easier to hang the giant glass curtain wall and support the main structure. This curtain wall was installed from the outside-in, via a massive crane, which is a more efficient technique than installing from the inside, as is typical in such buildings.

To keep the many height differentials from cluttering the facade, Gensler designed a unifying glass mosaic. This skin, or “veil,” is composed of alternating transparent, translucent, and fritted glass, along with units colored in blue, silver, and gray, all accented with metal panels. The veil’s glass becomes more transparent as it rises vertically, providing clear views for the condominiums while meeting Title 24’s new 60 percent transparency requirements. Because the glass all has the same light transmission value, the different colors offer the same amount of illumination on the interior.

The L-shaped building’s program, which features well over one thousand rooms, was also complicated because Marriott wanted to separate the Ritz rooms and amenities from those of the Marriott. They loaded both intersecting wings of the first segment with Marriott rooms, then stacked the Ritz portions above, creating an intimate Ritz entry on the 26th floor. The Marriott’s cavernous, 50-foot-tall lobby is located on the ground floor. That podium space makes a visual connection to L.A. Live and to downtown through glass facades that cantilever from the building frame to create point-supported “floating” walls. Each entity also has its own pool deck and private bar—the Marriott’s on the 4th floor and the Ritz’s on the 26th floor.


The colorful glass veil makes a statement on the skyline.

Another important element for any California building is earthquake-proofing. This tower uses a thin, steel-plate shear wall system instead of thicker concrete shear walls in order to speed construction and avoid concrete settling, while also increasing the square footage inside the building and maximizing views. The steel plates range from ¼ inch to ½ inch in width, instead of the usual three-foot-thick shear wall. In all, said Gensler principal Kap Malik, the process saved four months of concrete work and 4,000 yards of concrete, and allowed the building to rise four stories higher than a concrete structure would have allowed, increasing the value of the project by $8 million. The building is further braced horizontally with outrigger trusses at the 26th  and 53rd floors, an alternative to a thick concrete core. 

This thin steel system also required the use of fewer building materials, a sustainable strategy accompanied by water-efficient fixtures and landscaping, as well as solar reflecting materials on the roof. It’s not a groundbreaking list of green features, and the overall aesthetic of the building, while dynamic, is not earth-shattering. Still, the tower is a major step forward for L.A. Live, an urban project that has been sorely lacking in innovative design and urbanism.

Sam Lubell