Lotte Engineering and Construction announced on Oct. 12 that it will mount a large “diagrid” structure on top of the Lotte World Tower, which is currently under construction in Jamsil, Seoul. Once completed, it will be the tallest diagrid structure in the world.
A diagrid is a compound word of diagonal and grid, and it is a structure created out of diagonal braces.
Professor Kim Jong-rak of the School of Architecture at Soongsil University said, “A diagrid construction method is similar to the principle of a Jukbuin, or bamboo wife, which is made by crossing and weaving bamboo canes. Just like a bamboo wife, which has enough strength to maintain its structure even when the user lies on it despite the open bamboo structure, a diagrid also can withstand the weight of the building without large corner columns.”
The best part of the diagrid is to increase horizontal resistance to forces caused by typhoons and earthquakes. Lotte E&C Senior Researcher Jeon Hyun-soo said, “When the wind hits a diagrid, the diamond shape of the structure resists with a tensile force and a compressive force in turn, enhancing the ability to withstand typhoons and earthquakes.” The Lotte World Tower can withstand 80 m/s winds and earthquakes measuring up to nine on the Richter scale with its cutting-edge diagrid and outrigger and belt truss on the spire, which increases the lateral force resistance.
There is only one central column that supports the whole building through the diagrid in the spire of the Lotte World Tower. Since there is no need to put up additional interior columns or buttresses, wide open spaces are possible on the inside, like the uninterrupted view of an observatory.
The diamond pattern of the diagrid also makes the exterior wall of the building beautiful. The structure on the Lotte World Tower, which is frequently used in skyscrapers and cleverly-designed buildings, will become progressively narrower going up the building in a bid to increase the building’s esthetic effect.
The diagrid will be a large 120-meter structure that supports from the 107th floor of private offices to the top of the building (555 meters), including an observatory.
Lotte E&C is planning to set the foundation to become a leader in the skyscraper construction market, and continuously expand it in the future through its new technologies related to high-rise buildings such as a high-rise diagrid method and super high strength concrete vertical pumping technology.
Meanwhile, the Lotte World Tower completed 100 of the projected 123 floors on March 24 this year, and the 111th floor is currently under construction. After finishing the construction of the exterior of the 123 floor, 555 meter high edifice by the end of this year, the Lotte Group will continue to complete the interior during the following year. The building is expected to be completed by the end of 2016.