Ark Hills Sengokuyama Mori Tower

The Ark Hills Sengokuyama Mori Tower (アークヒルズ仙石山森タワー) is a 206.7 m mixed-use skyscraper in Roppongi, Minato ward, Tokyo. The building was designed by Irie Miyake Architects and Engineers and Pelli Clarke Pelli Architects; Mori Building Company was the developer, while the construction process was managed by Obayashi Corporation. Construction of the tower started in 2009 and was completed in 2012.

The building is situated on 2 ha of land area in Ark Hills, near the Kamiyachō Station on the Tokyo Metro Hibiya Line and the Roppongi-itchōme Station on the Tokyo Metro Namboku Line. The tower is surrounded by gardens that were designed to replicate the natural wildlife in Tokyo.

Seismic design
The building was designed to withstand earthquakes and strong winds by using two different types of mass dampers. The first damper type is the viscous vibration damping walls (the "sticky wall") that was designed to sustain small- and medium-size earthquakes, while the second damper type is the brake damper that was designed to sustain major earthquakes.

Facade and primary uses
The primary functions of the building are distinguished by its facade. The retail and commercial uses of the building, which are located on floors 1–2, are represented by the glass and stone facade with the squared-shape building corners; the apartments, which are located on floors 3-24, are distinguished by its balconies with the rounded-shape building corners; while the offices, which are located on floors 25–47, are covered by the glass with the building corners are subtly stepped back, forming the cone-like shape on the upper parts of the building.