In this post, I would like to share some of the interesting photos taken during the technical visit to Shinjuku Mitsui Building which is located in Nishi-Shinjuku area in Tokyo, Japan.
The Shinjuku Mitsui Building is a high-rise building in Nishi-Shinjuku area in Tokyo and it is owned by Mitsui Fudosan. It is one of the 10 tallest buildings in Tokyo and was the tallest building in Japan from September 1974 until March 1978. The photo of the skyscraper is shown in the figure below.
Figure 1. Shinjuku Mitsui Building
The building was subject to substantial long-period ground motion during Great East Japan Earthquake on March 11, 2011, and was observed to sway approximately 2 meters. Although the building was a structurally rated, Ministerial-approved building that provided a high level of safety, and its seismic performance was proved to be fully adequate during the earthquake, there were increased concerns among tenants about the safety and security of the building since the earthquake. Therefore, the building owner decided to upgrade the structure by installing Tuned Mass Dampers (TMDS) to further strengthen the structure against even stronger earthquakes and to provide peace of mind for the occupants.
Figure 2. Sketch of Shinjuku Mitsui Building with TMDs
TMDs are simply gigantic pendulum-like counterweights that are placed on the top of the structure and tuned to pull a building’s mass in the opposite direction of the prevailing vibrations. So when the ground beneath a foundation moves laterally—either because of the wind or seismic activity—the counterweight moves in the opposite direction, taking the structure with it.
Figure 3. Photo of a Tuned Mass Damper on the top of Shinjuku Mitsui Building.
The video below simulates the building behavior during the earthquake with and without TMDs.
Video 1. Earthquake simulation of Shinjuku Mitsui Building with and without TMDs
Installing TMDs to the Shinjuku Mitsui Building cost approximately $50 million.
In the below photo me and three other ESRs are on the roof of the Shinjuku Mitsui Building.
Figure 4. ESRs on the top of the Shinjuku Mitsui Building. From left to right - Me (ESR 7), Matteo Vagnoli (ESR 9), John James Moughty (ESR 10), Antonio Barrias (ESR 11)