The Korea Institute of Civil Engineering and Building Technology (KICT) said on the 2nd that it has developed a "stiffness-adjustable tuned mass damper (TMD) technology" that can be easily installed in modular buildings and can reduce floor vibration by more than 70%.
A tuned mass damper, also called an "earthquake damper," is a device mounted on a structure to reduce mechanical vibration. The tuned mass dampers currently applied to general buildings are designed and manufactured one-to-one to match the natural frequency, and if the natural frequency changes after installation, problems such as performance degradation or vibration amplification may occur.
In addition, modular buildings made of steel have low mass and low damping, making them highly sensitive to everyday vibrations. In fact, post-occupancy evaluation results for some modular buildings have reported cases where satisfaction with external vibrations and noise was low.
To solve these problems, research team leader Lee Sang-seop of KICT's Building Research Division and his team developed a stiffness-adjustable tuned mass damper that can be easily installed on modular building floors and, even after installation, can fine-tune the design frequency in 0.1 hertz increments with secured functionality and safety.
This technology meets building structural standards while demonstrating a floor vibration reduction effect of about 70% or more, and the frequency can be finely adjusted in 0.1 hertz increments in the 5.1–6.9 hertz range. An assemble-to-order (ATO) production method can be applied, making it advantageous for mass production going forward.
The floor anchoring system applying this technology secured safety up to a seismic acceleration of 0.83g in a shake-table test under international standards (ICC-ES AC156). This is similar to the peak ground acceleration (PGA) level during the 1995 Great Hanshin-Awaji Earthquake in Japan.
KICT said it jointly developed this technology with NSV and transferred the technology. It is expected to become a key solution to address vibration issues in modular apartment complexes that are getting taller and larger. In particular, while modular methods are being introduced in military facilities such as barracks, distribution has been delayed due to vibration issues, and the institute sees this as a turning point that can overcome structural limitations.
President Park Seon-gyu said, "As construction of modular apartment complexes grows taller and larger, this technology will raise resident satisfaction and also help energize the modular construction market," adding, "KICT will continue to take the lead in developing practical technologies that improve people's quality of life."