|Dr. N. Subramanian
Joined: 21 Feb 2008
Location: Gaithersburg, MD, U.S.A.
|Posted: Wed Dec 01, 2010 9:41 pm Post subject: Hearst Tower and Diagrid Framing System
|Diagrid Framing System
Diagrid (a portmanteau of diagonal grid) is a design for constructing large buildings with steel that creates triangular structures with diagonal support beams. It requires less structural steel than a conventional steel frame. Hearst Tower in New York City, designed by Sir Norman Foster, reportedly uses 21 percent less steel than a standard design. The Diagrid also obviates the need for large corner columns and provides a better distribution of load in the case of a compromised building. Another building designed by Sir Norman Foster, 30 St Mary Axe, known as "the Gherkin", also makes use of this structural system.
Buildings utilizing diagrid
* Hearst Tower (New York City)
* 30 St Mary Axe - Swiss Re building ("the Gherkin")
* The first design for the Freedom Tower at the World Trade Center site in New York, New York included the use of a diagrid perimeter.
* CCTV Headquarters in Beijing, China
* The Bow, Calgary, Canada
* Seattle Central Library, Seattle, Washington
* Capital Gate, Abu Dhabi, Abu Dhabi Emirate
Hearst Tower (New York City)
Hearst Tower in New York City, New York is located at 300 West 57th Street, 959 8th Avenue, near Columbus Circle in Midtown Manhattan. It is the world headquarters of the Hearst Corporation, bringing together for the first time their numerous publications and communications companies under one roof, including among others Cosmopolitan, Esquire, Marie Claire, Harper's Bazaar, Good Housekeeping, Seventeen, and the San Francisco Chronicle.
The six-story base of the headquarters building was commissioned by the founder, William Randolph Hearst and awarded to the architect Joseph Urban. The building was completed in 1928 at a cost of $2 million and contained 3,700 m2. The original cast stone facade has been preserved in the new design as a designated Landmark site. Originally built as the base for a proposed skyscraper, the construction of the tower was postponed due to the Great Depression.
The new tower addition was completed nearly eighty years later, and 2,000 Hearst employees moved in on 4 May 2006.
The tower – designed by the architect Norman Foster, structural engineered by WSP Cantor Seinuk, and constructed by Turner construction – is 46 stories tall, standing 182 meters with 80,000 square metres of office space. The uncommon triangular framing pattern (also known as a diagrid) required 9,500 metric tons of structural steel – reportedly about 20% less than a conventional steel frame. Hearst Tower was the first skyscraper to break ground in New York City after September 11, 2001. The building received the 2006 Emporis Skyscraper Award,[citing it as the best skyscraper in the world completed that year.
Hearst Tower is the first "green" high rise office building completed in New York City, with a number of environmental considerations built into the plan. The floor of the atrium is paved with heat conductive limestone. Polyethylene tubing is embedded under the floor and filled with circulating water for cooling in the summer and heating in the winter. Rain collected on the roof is stored in a tank in the basement for use in the cooling system, to irrigate plants and for the water sculpture in the main lobby. 85% of the building's structural steel contains recycled material. Overall, the building has been designed to use 26% less energy than the minimum requirements for the city of New York, and earned a gold designation from the United States Green Building Council’s LEED certification program, becoming New York City's first LEED Gold skyscraper.
The atrium features escalators which run through a 3-story water sculpture titled Icefall, a wide waterfall built with thousands of glass panels, which cools and humidifies the lobby air. The water element is complemented by a 21 m-tall fresco painting titled Riverlines by artist Richard Long.
You may read the article
Proposed Methodology to Determine Seismic Performance Factors for Steel Diagrid Framed Systems by William Baker, Charles Besjak, Mark Sarkisian, Peter Lee, Chung-Soo Doo in the link: http://www.ctbuh.org/LinkClick.aspx?fileticket=PAas26PhFw8%3d&tabid=59&language=en-US