Atomic Bomb Dome Preservation Project Ⅳ

Preservation Project Ⅳ was undertaken from Fy2015 to Fy2016 to earthquake-proof the Atomic Bomb Dome in order to minimize damage in the event of an earthquake.

Earthquake-Proofing (Addition of Steel Reinforcements)

Fundamental Policies

As the Atomic Bomb Dome is registered as a World Heritage site, it is necessary that we work to maintain the building’s worth as a cultural asset. Our fundamental policies regarding preservation work are as follows:

1. As a general rule, no changes affecting the exterior appearance of the Atomic Bomb Dome will be made.
2. Only the absolute minimum necessary measures will be taken.
3. All work will be, as far as possible, reversible.

Earthquake-Proofing Objective

To prevent damage on a devastating scale that would render the Atomic Bomb Dome difficult to restore.

Anticipated Earthquakes

We anticipate the occurrence of Geiyo Earthquakes, which originate from the Akinada Sea-Iyonada Sea-Bungo Channel, as they have occurred there periodically over relatively short intervals of 50-100 years and have historically caused damage and destruction across Hiroshima Prefecture.

Analytical Survey of the Current State of the Atomic Bomb Dome

We determined that the unsupported portions of the walls that remain standing on the upper levels of the Atomic Bomb Dome were swaying back and forth to quite a large extent; the walls in these areas are thin and they were not horizontally reinforced. Consequently, this indicated that these walls were points of stress concentration. Through the use of 3D finite element analysis software, we were able to quantitatively determine which areas of the walls were points of stress concentration.

The Earthquake-Proofing Process

As the unsupported portions of the walls that remain standing on the upper levels of the Atomic Bomb Dome are subject to stress above a certain level, it was feared that they would collapse in the event of an earthquake. To resolve this issue, we used a reinforcing method that involved adding steel reinforcements on these walls in three places with the intention of minimizing collapse.

Given the large disparity in the condition of brickwork and other materials, it was concluded that, even if we had reinforced these elements during Project Iv, they would not escape damage in the event of a large earthquake. Therefore, we decided that any areas of the Atomic Bomb Dome that sustain damage during a large earthquake will be restored in line with survey materials, such as 3D survey data of the current state of the building.

Inquiries regarding this page

Park Development Division, Greenery Promotion Department, Urban Development Bureau
Tel: 082-504-2393 // Fax: 082-504-2391
Email: park@city.hiroshima.lg.jp