Japanese Firms Develop Giant Steel Pendulums to Keep Skyscrapers From Swaying During Earthquakes

Posted on August 1, 2013

Rooftop Pendulums on the Shinjuku Mitsui Building


The Asahi Shimbum reports that Mitsui Fudosan Co., a real estate developer, and Kajima Corp., a general contractor, have developed giant steel pendulums that can be installed on the top of skyscrapers to reduce swaying during major earthquakes. The companies say the pendulums will apply force in the opposite direction of seismic motions and reduce the amplitude of vibrations from an earthquake by 60%. A graphic provided on the article shows how it would work. The illustration above shows the proposed pendulum devices in blue.

The companies want to first put the seismic control device on the Shinjuku Mitsui Building in Tokyo. This building is 55-stories high. The installment would include six pendulum devices, each weighing 300 tons. The Asahi Shimbum says the building sustained horizontal vibrations of 2 meters during the 9.0-magnitude 2011 Tohoku Earthquake.

Photo: Mitsui Fudosan