E-Defense
| E-Defense | |
|---|---|
E-ディフェンス | |
 | |
 | |
| General information | |
| Location | Miki, Hyōgo |
| Country | Japan |
| Coordinates | 34°46′42″N 135°03′19″E / 34.7784°N 135.0554°E |
The 3-D Full-Scale Earthquake Testing Facility[1] or E-Defense (Japanese: E-ディフェンス) is an earthquake shaking table facility in Miki, Hyōgo Prefecture, Japan.[2] Operated by the Japanese National Research Institute for Earth Science and Disaster Resilience,[3] it is the largest 3D earthquake shake table in the world.[2][3]
History
[edit]After the destructive Great Hanshin earthquake of 1995 occurred, the Science and Technology Agency established the Round-table Conference for the Study of Bases of Research. In May 1996 the conference made the recommendation that an earthquake research base be founded to prevent future earthquake damage in urban areas. It was recommended that the research base have a three-dimensional shake table.[4]
Development of the table's actuators began in 1995, and the design and construction of E-Defense itself began in 1998[5][6] or 1999[7] (sources vary) with the goal of replicating the ground motions of the Great Hanshin earthquake.[3] Mitsubishi Heavy Industries Machinery Systems designed and constructed the facility,[8] which is located at Miki Earthquake Disaster Memorial Park.[4][9] Construction of the table's foundation started in 1999 and was completed by 2001.[5] Operations began in 2005,[3] after a total construction cost of 45 billion yen.[4] The nickname "E-Defense" was selected in a public competition, with the letter "E" standing for Earth.[7][4]
E-defense was not able to reproduce ground motions of the 2011 Tōhoku earthquake due to the shaking having long periods and a long duration. NIED tried to use the ground motions of the earthquake for five minutes, but was initially only able to manage 1.5 minutes due to not having enough oil for the actuators. After more accumulators were installed and bypass valves were added to the actuators, five minutes was able to be achieved.[1]: 987
Facility
[edit]The table has a size of 20 by 15 metres (an area of 300 square metres), making it the largest earthquake shaking table in the world.[2][3] It can move in the x, y, and z directions, and perform yaw, pitch, and roll rotations. It can accelerate up to 1 g horizontally in both directions, and up to 1.5 g vertically. It can have a maximum payload of 1,200 tons.[3][2][4] The table has 5 horizontal actuators for both directions, and 14 vertical actuators, each with a maximum driving force of 4,500 kilonewtons. They can generate frequencies with good accuracies up to 15 hertz, and can be increased to 30 hertz with lower accuracy. Universal joints are placed between the actuators and the table.[3]
The facility is on a six-hectare site, which includes several buildings. These are the Experiment Building, which contains the shaking table; the Operation Building, which contains the control system for the shaking table; the Hydraulic Unit Building, which contains equipment that powers the shaking table; and the Preparation Building, where test structures are prepared.[4]
Experiments
[edit]As of 2020, 113 experiments have been run of the table, at an average of 7.1 experiments per year.[1]: 986 Experiments are either projects run by the NIED, projects run jointly by the NIED and other organisations, or run by other organisations.[1]: 986 Most of the time designing and constructing experiments takes place outside the main E-Defense facility in order to maximise the use of the table. Experiment structures are placed onto the table using two cranes which have a combined maximum loading capacity of 9000 kilonewtons.[3]
Due to the high cost of running the experiments, it is E-Defense policy that the results not be intellectual property of the conductors of the experiments, but instead shared by the earthquake engineering community. This is so that the results can have a high impact.[1]: 992
References
[edit]- ^ a b c d e Horiuchi, Toshihiko; Ohsaki, Makoto; Kurata, Masahiro; Ramirez, Julio A.; Yamashita, Takuzo; Kajiwara, Koichi (2022). "Contributions of E-Defense Shaking Table to Earthquake Engineering and its Future". Journal of Disaster Research. 17 (6): 985–999. doi:10.20965/jdr.2022.p0985.
- ^ a b c d "Largest 3D earthquake shake table". Guinness World Records. Retrieved 26 September 2024.
- ^ a b c d e f g h Nakashima, Masayoshi; Nagae, Takuya; Enokida, Ryuta; Kajiwara, Koichi (January 2018). "Experiences, accomplishments, lessons, and challenges of E-defense—Tests using world's largest shaking table". Japan Architectural Review. 1 (1): 4–17. doi:10.1002/2475-8876.10020. ISSN 2475-8876.
- ^ a b c d e f "3-D Full-Scale Earthquake Testing Facility (E-Defense)" (PDF). January 2005. Retrieved 26 September 2024.
- ^ a b "Project "E-Defense" -Introduction of E-Defense" (PDF). Pacific Conference on Earthquake Engineering. 2003. Retrieved 26 September 2024.
- ^ "Construction of E-Defense (3-D Full-Scale Earthquake Testing Facility)" (PDF). 2004. Retrieved 3 October 2024.
- ^ a b "E-Defense（Profile)". www.bosai.go.jp. Retrieved 2024-09-26.
- ^ "A magnitude 7 earthquake is faithfully reproduced in every detail!". Mitsubishi Heavy Industries. Retrieved 26 September 2024.
- ^ www.bosai.go.jp https://www.bosai.go.jp/hyogo/3de/emap.htm. Retrieved 2024-10-03.
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Further reading
[edit]- "E-Defense Experiments On Full-Scale Wooden Houses" (PDF). World Conference on Earthquake Engineering. 2008.