Gym workout shakes building
South Korean experts said they believe a vigorous gym exercise session caused a high-rise building in the capital to shake for 10 minutes this month, prompting hundreds to flee in panic.world Updated: Jul 20, 2011 00:30 IST
South Korean experts said they believe a vigorous gym exercise session caused a high-rise building in the capital to shake for 10 minutes this month, prompting hundreds to flee in panic.
They said tests showed that oscillations created by a group of Tae Bo practitioners on the 12th floor of the 39-story TechnoMart mall building apparently resonated through the structure.
Tae Bo is an aerobic exercise routine that involves performing the motions of boxing and martial arts such as Taekwondo at a rapid pace. Professor Chung Lan of Danguk University in Yongin City near Seoul linked the incident to a physics principle under which catastrophic failures can occur when the vibration of a structure is matched by another source.
He said that the building, constructed from iron girders and cement, had a characteristic vibration frequency which was "in phase" with the synchronised movements of the Tae Bo practitioners.
Chung and six others re-created the scenario which caused the panic on July 5 - with a group of 17 middle-aged people working out to the tune of a pop song, "The Power" by German group Snap - and said the building shook in a similar way.
On the first occasion hundreds fled the building as it shook for about 10 minutes. The Gwangjin district government ordered the mall closed but reopened it after experts said it was structurally sound.