DL E&C "The Cause of Seoul Forest Shaking is Resonance Phenomenon"

"No Safety Issues Detected"

[Asia Economy Reporter Kim Jin-ho] The cause of the vibration that occurred at Acro Seoul Forest, a high-rise mixed-use building located in Seongsu-dong, Seongdong-gu, Seoul, has been investigated and identified as a 'resonance phenomenon.'

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DL E&C announced on the 24th that it reached this conclusion by installing precise measuring instruments on key floors and conducting reproduction experiments to identify the cause of the vibration phenomenon that occurred on some floors of the D Tower Seoul Forest office building.

The 'resonance phenomenon' refers to the effect where the vibration frequency generated internally or externally matches the building's natural vibration frequency, causing the amplitude of the vibration to increase.

The experiment and analysis involved the Architectural Institute of Korea and top structural experts in the country, including Professor Park Hong-geun of Seoul National University’s Department of Architecture (President of the Korean Concrete Institute), Professor Lee Sang-hyun, Research Professor Moon Dae-ho, and Professor Yoo Eun-jong of Hanyang University, who are renowned experts in building noise and vibration.

The experiment was conducted by mobilizing multiple people to generate vibrations at a consistent rhythm and securing measurement data on each key floor. The results indicated that the vibration that occurred on the 20th was caused by a slight floor slab shaking due to a type of resonance-induced micro-vibration.

Professor Yoo Eun-jong diagnosed, "No issues were found in the design and construction process," adding, "The phenomenon of slight floor slab shaking was caused by complex impacts occurring on multiple floors of the building or repetitive movements of people inside the building."

DL E&C and the advisory professors also confirmed that simple damages such as broken windows or leaks were unrelated to this vibration and were issues that appeared during the building’s use after occupancy.

DL E&C added, "Although it was confirmed that the vibration does not affect the building’s safety, we plan to prepare technical support measures to reduce the vibration after verification by the Architectural Institute of Korea to alleviate the concerns of the tenant employees."