30% of old buildings in Tokyo at risk of collapse in strong earthquake

The New Shimbashi Building (c1971) poses a high risk of collapse in a major earthquake. There are plans to eventually redevelop this building into a high-rise although negotiations with land-owners are taking longer than anticipated.

On March 29, the Tokyo Metropolitan Government released data from earthquake resistance inspections on public buildings built to the old ‘kyu-taishin’ earthquake codes (pre-May 1981). A total of 251 kyu-taishin buildings, representing a third of the total, were determined pose some risk of collapse in the event of an earthquake producing a seismic intensity scale (shindo) of a 6-upper or above. Of those, 156 were found to be at high risk of collapse.

The publication of this data is the result of a revision to the Act for Promotion of Renovation for Earthquake-Resistant Buildings that was introduced in November 2013. Under this revision, public buildings used by an unspecified number of people, such as hotels and commercial facilities, with a floor area over 10,000 sqm and built to the old kyu-taishin earthquake codes are obligated to carry out earthquake resistance inspections, the results of which are made public. This also applies to old buildings located alongside emergency roads. Although the revision requires building owners to carry out inspections, there are no obligations or requirements to conduct the retrofitting.

In the Tokyo metropolitan area, 852 buildings are subject to this revision.Of the 18,453 buildings that front onto emergency roads, 74% meet the latest earthquake codes, and approximately 11% do not. The inspection reports can be viewed at the Tokyo Metropolitan Government’s webpage here.

Some of the buildings that have received a risk designation include:

Kinokuniya Building, Shinjuku (1964)

This was built as the head office of the Kinokuniya bookstore in 1964. The 9-storey multi-tenant building was designed by famed modernist architect Kunio Maekawa (1905-1986), a former apprentice of Le Corbusier. In 2016 it received a designation by the Tokyo government as a selected heritage building. Kinokuniya is currently considering possible ways to retrofit the building without altering the modernist facade.

Kinokuniya Building, Image via Kinokuniya.

Science Museum (1964)

The Science Museum’s main building and annex in Chiyoda’s Kitanomaru Park are both at risk of collapse. The museum is planning to retrofit three of their buildings later this year, with the main building to be retrofitted in 2021. The main building was built in 1964.

Shin-Kioicho Building (1983)

A mixed-use office, residential and banquet hall building located adjacent to the Hotel New Otani, and partially owned by New Otani. The banquet hall has already been retrofitted, with other walls in the building to be reinforced by the end of the year. Although this building was completed in February 1983 – almost two years after the new earthquake codes were introduced – planning and construction may have started before the revision to the building act. It is possible to find buildings completed a few years after 1981 that were built to the pre-1981 earthquake codes.

Shibuya 109

A landmark shopping mall in the heart of Shibuya. The 40-year old building received a high-risk designation. Retrofitting will be completed by 2019.

Nakano Broadway

A 10-storey shopping mall and condominium complex filled with stores selling manga and anime items. The building’s shops and apartments are all individually owned, which is making it very difficult to obtain enough votes to approve retrofitting. The building was completed in 1966 and given an ‘at-risk’ designation in the event of a shindo 6+ earthquake.

Toho Twin Tower Building

A 9-storey building located across the street from the recently opened Tokyo Midtown Hibiya. The building is owned by Toho Real Estate, a subsidiary of the Toho cinema and film company, and was built in 1969. The building is in the process of being retrofitted.

Yomiuri Kaikan (BicCamera Yurakucho) (1957)

Designed by Togo Murano and completed in 1957, this is a 9-storey commercial building that includes the BicCamera electronics store on the lower levels and the Yomiuri Hall on the top two floors. It is currently in the process of being retrofitted with completion expected by 2026.

Roppongi Kyodo Building (Roi Building) (1973)

Located alongside Roppongi’s main bar and nightlife street, this 14-storey building is home to numerous bars, clubs, restaurants, and a murder. It has a seismic index of 0.35 and is designated as high-risk. This building is likely to be redeveloped in the future.

Some of the buildings determined to be at low-risk and not in need of retrofitting:

Nissay Theatre (1963)

A modernist, 8-storey building designed by architect Togo Murano and located across the street from the Imperial Hotel. This is a leading example of Japan’s Showa-era architecture. The building’s seismic index is 1.05 (anything under 0.3 poses a high-risk of collapse in a shindo 6 ~ 7 earthquake).

Meiji Jingu Stadium (1926)

A baseball stadium located near the new Olympic Stadium. It opened in 1926 and has hosted Lou Gehrig and Babe Ruth. Although designated as low-risk, the stadium may be redeveloped and modernized in the near future.

Tokyo Tower

Tokyo’s symbol. Built in 1958 as a communications tower, it is the second tallest structure in Japan. It has a seismic index of 1.05.

Mitsukoshi Department Store, Nihonbashi (1935)

Built in 1935, the department store building is designated as a National Important Cultural Property. It has a low-risk designation.

Sources:
The Tokyo Shimbun, March 30, 2018.
The Nikkei Shimbun, March 29, 2018.
The Tokyo Metropolitan Government, March 30, 2018.