Toranomon Hills Mori Tower is a high-rise building situated in the heart of Tokyo. Standing about 247 metres tall on a 6000-square-metre site, the 52-storeyed skyscraper is the tallest building in Tokyo.

A four-lane underground urban motorway was planned directly beneath this building as a new main traffic artery for getting across Tokyo. To prevent vibrations from the tunnel housing the motorway, a solution was needed so that the skyscraper could be built to the required usage standards.

The Tokyo Metropolitan Government selected the Japanese property company Mori Building as its partner for this major public-private sector project. Mori, in turn, engaged Getzner as its specialist partner for vibration isolation.

Getzner’s vibration protection solution involved two significant subprojects implemented in two phases: an elastic solution for the hotel on the uppermost floors of the high-rise complex and a solution for the urban motorway running directly underneath the building.

The Getzner solution:

Full-surface bedding of the 4-lane urban motorway

In the first phase, a resilient bedding was applied to the 200-metre underground length of the motorway. The full width of this section was bedded on the high-tech Sylomer mats, providing the structure above with effective and long-term protection against vibration. The solution directly addressed the cause of the vibration – the four-lane urban motorway, which was the source of the disturbing structure borne noise, and was now isolated. The elastic bedding decouples the source of disturbance from its surroundings, and thus also from the structure erected over it.

Vibration damping of the building’s upper floors

In the second phase of the project, several internal vibration-damping construction measures for decoupling the hotel on the upper floors of the tower were carried out. In order to protect this sensitive area in the best possible way against vibrations, Getzner bedded the hotel floors, the pool areas and the fitness and machinery rooms of the hotel on Sylomer mats. This prevented structure borne noise from spreading through the building, effectively protecting the building against unwanted vibrations.

Vibration experts on site

Getzner managed the entire installation process, working with their Japanese partners to constantly monitor the quality of work and ensure that their vibration isolation solutions protected the superb architecture well into the future.

“Installing Sylomer mats has the effect of reducing noise and vibration. The material has been employed successfully for decades – Getzner has demonstrated this on numerous occasions in the rail sector. Another important criterion for future-oriented urban planning is that the material should be easy and quick to install,” Toru Tsuchihashi, deputy general manager, Mori Building said.