Seismic Isolation ProjectsEnergy Dissipation Projects
Seismic Isolation Projects
Koto Building, Kobe, 1997
Amitie Shinosaka, Osaka, 1998
The Koto Building is a privately owned office building. It is 8 stories over a basement and is isolated with 12 lead rubber bearings. The previous building on the site was severely damaged in the Kobe earthquake. The owner went back to the same
construction company (Takenaka) some 30 years later to build this building.
Mitsui Marine & Fire Insurance Building, Chiba, 1994
The Amitie Shinosaka building is a company owned "dormitory". It utilizes high damping rubber bearings. This structure was designed to be a highly earthquake-resistant building for Shimizu engineers, managers and researchers to use as a location from which to respond to future Kansai area earthquakes.
Nakanoshima Kokaido, Osaka. Original Construction 1896, Retrofit 2000
The Mitsui Marine and Fire Insurance Building (BCJ-64) serves
as the company's computer data center. As is common in Japan, the building has separate isolation and damping elements. The isolation system comprises 88 natural rubber bearings, while the damping system comprises 12 friction dampers and 144 lead dampers.
National Museum of Western Art, Ueno, Tokyo. Original Construction 1959, Retrofit 1998
The Nakanoshima Kokaido building is the first US-style historic building retrofit in Japan. Construction of the retrofit is
expected to start in 2000.
The National Museum of Western Art (BCJ-232) was designed by Le Corbusier in 1959 and isolation retrofitted in 1998. The retrofit involved the placement of 42 high damping rubber bearings below the original spread footing foundation system. Shake table testing was done to verify the dynamic behavior of the expansion joint system utilized in the retrofit.
One of the distinctly different aspects of the application of isolation in Japan compared to the U.S. is the widespread use of the technology for residential structures. While there is
only a handful of examples of isolation applied to residential structures in the U.S., there are now more than 200 isolated residential buildings in Japan, nearly all of which are large condominium structures designed and constructed after the 1995 Kobe earthquake.
Kobe Central Fire Station, Kobe, 1998
NTT Power and Building Facilities, the design arm of NTT (Nippon Telephone and Telegraph),was established as an independent company in 1992. The company, commonly known as NTT-Facilities, comprises a total of about 6000 people providing services to the power and building divisions of NTT, as well as various entities outside of the NTT group. In recent years it
has experienced significant design and construction activity in the wireless communications sector, and especially for NTT's cellular subsidiary, NTT-DoCoMo. Wireless communications systems are seen as essential systems in Japan, and thus the seismic design of buildings, towers and other structures for the wireless networks is to the highest performance standards. Seismic isolation and energy dissipation have been used extensively, and these pictures give some idea of the variety of
structures using the technologies.
The Kobe Central Fire Station (BCJ-500) is an example of isolation applied to an essential facility, similar to several U.S. projects. Prior to the Kobe earthquake there were few Japanese examples of isolation applied to essential (emergency response, communications, police and fire) facilities, whereas today there is a steadily growing number of these types of isolated buildings. This reinforced concrete building has 10 stories plus an additional
basement level. The isolation system comprises 12, 1.3m diameter lead rubber bearings.
Energy Dissipation Projects
Osaka International Convention Center, 1999
Dai-ichi Seimei Sannomiya Building, Kobe, 1998
The Osaka International Convention Center has 13 stories plus 3 basement levels, with a total floor area of
67,031 square meters (721,516 square feet). The structural system is made up of moment frames ("super frame" towers) plus Unbonded Braces made by Nippon Steel Corporation. More than three quarters of all new high-rise (over 60m in height) buildings in Japan use some sort of passive energy dissipation system.
SUT Building, Shinzuoka, 1993
The Dai-ichi Seimei Sannomiya Building is owned by an
insurance company. This 13 story building makes use of Low Yield Point steel torsion dampers and buckling restrained braces.
The SUT building uses more than 180 viscous damping walls (VDW) to achieve structural system damping of 20-30%. This is perhaps the most dramatic example of passive damping in a high rise building to date.