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Completion of the “Heisei Refurbishing Work” on the “Three-Storied Pagoda in the Chinzan-so Garden,” One of Three Old Pagodas Existing in Tokyo

—Earthquake- measures to protect traditional architecture from earthquakes—

July 13, 2011Takenaka Corporation

The earthquake-resistance strengthening and refurbishing work which Takenaka Corporation (President: Toichi Takenaka) has been carrying out on the “Three-Storied Pagoda in the Chinzan-so Garden” (in Sekiguchi, Bunkyo-ku) since September 2010 has been completed. This “Heisei Refurbishing Work” is the first refurbishing work to be carried out since the pagoda was moved from Takamurayama Chikurinji Temple in Hiroshima Prefecture, in 1925, and involved the replacement of parts of the eaves that were damaged, and the replacement of the copper-plated roof. Takenaka implements measures to protect traditional architecture from earthquakes, and in this project earthquake-resistance measures have been implemented using the company’s unique “superplastic zinc-aluminum alloy structural control dampers for traditional wooden structures.”

The Three-Storied Pagoda in the Chinzan-so Garden

【Features of the work】

Structural strengthening

The length of the joints of the central main column of the pagoda was too short and unstable, so a longer column without a joint was installed. Also, there were not enough horizontal supports in the first, second and third roofs, so a horizontal structural member set in a grid pattern (called igeta) was installed in each of the roofs to support the load from the upper part of the structure, thereby powerfully strengthening the whole structure. The igeta also functions to spread the vertical load, which was previously supported by just the corner rafters and the corner tail rafters.

Structural control without changing the exterior or interior appearances

By using a total of 16 “superplastic zinc-aluminum alloy structural control dampers for traditional wooden structures” in the first and second floors, the shaking during an earthquake has been reduced by about 20 percent compared to not using these dampers. By installing these dampers where the columns and the column boards (wide, flat parts used to support columns in the next level up) are joined, the earthquake resistance of this historical “Three-Storied Pagoda in the Chinzan-so Garden” has been improved without changing the exterior or interior appearances.

【Outline of the work】

Project name Heisei Refurbishing Work of the Three-Storied Pagoda in the Chinzan-so Garden
Work period September 2010 to May 2011
Number of floors/Structure 2 fl. aboveground, Steel
Location 2-10-8 Sekiguchi, Bunkyo-ku, Tokyo
Client Fujita Kanko Inc.
Design/Construction Takenaka Corporation

【About the Three-Storied Pagoda in the Chinzan-so Garden】

The Three-Storied Pagoda in the Chinzan-so Garden was originally constructed at the Takamurayama Chikurinji Temple that was in Kamo-gun (present day Higashi Hiroshima City) in Hiroshima Prefecture. According to Engi picture scrolls, this temple was founded by Ono Takamura (802 – 852), a poet of the Heian Period, and from the architectural style, it was thought that the Three-Storied Pagoda was constructed in the late Muromachi Era. However, the results of dendrochronology analysis carried out during this restoration work have shown that some parts of the structure date back to about 1420, in the early Muromachi Era. The pagoda was brought to Chinzan-so in 1925 by Baron Heitaro Fujita, the second-generation head of Fujita and Co., Ltd. (founded by Baron Denzaburo Fujita), who received the garden from Field Marshal Prince Yamagata Aritomo. Remarkably, the pagoda was spared during air raids on May 25, 1945, and today has become a symbol of Chinzan-so.

【Earthquake-resistance work for traditional structures carried out by Takenaka】

Name of building Completion Work content
Yutenji Temple Main Hall and Residence (Meguro-ku, Tokyo) 2010 Base isolation
Toshodaiji Temple (Nara, Nara Prefecture) 2009 Structural analysis and strengthening proposals for preservation work
Takebe Taisha Shrine Main Hall and Temporary Hall (Otsu, Shiga Prefecture) 2006 Base isolation
Tsurugaoka Hachiman-gu Shrine Maidono Pavilion (Kamakura, Kanagawa Prefecture) 2006 Structural control strengthening