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Jan 9, 2024 · These changes first began a century ago, when a 7.9-magnitude earthquake in Yokohama, Japan, killed 140,000 people and toppled hundreds of thousands of structures in 1923.
- Elizabeth Fazzare
Jan 5, 2024 · Porter notes that many older Japanese buildings are traditional post and beam wood frame construction, which “tends to be very fragile” and vulnerable to earthquake damage. Following another deadly earthquake in 1995, Japan began focusing on retrofitting older architecture to be more resilient to earthquakes. Of course, none of this is ...
- Evolution of Japan’s Earthquake Resistance Laws and Regulations
- Understanding Anti-Seismic Performance Levels
- How Building Structure Influences Seismic Resilience in Japan
- Exploring The Variety of Building Structures and Materials in Japan
- Assessing Earthquake Damage Risk Across Different Areas in Tokyo
- Conclusion
1971: Enhancing Standards for RC Structures
Following the 1968 earthquake off the coast of Tokachi, which registered a maximum JMA seismic intensity scale of 5, the standards for tie-hoops of RC (reinforced concrete) structures were enhanced.
1981: Implementation of New Anti-seismic Design Standard
The earthquake off the coast of Miyagi Prefecture in 1978, which also registered a maximum JMA seismic intensity scale of 5, led to a revision of the Building Standard Act. The New Anti-seismic Design Code was introduced, focusing not only on preventing building collapse during earthquakes but also on ensuring the safety of the occupants.
2000: Strengthening Standards for Wooden Structures
The devastating Great Hanshin Earthquake of 1995, which reached a maximum JMA seismic intensity scale of 7, prompted another revision of the Building Standard Act. This revision aimed to enhance the safety of wooden buildings and clarify anti-seismic performance levels, specifications, and building foundation forms. Ground investigations became virtually mandatory. With the implementation of the Housing Quality Assurance Promotion Act (Housing Quality Assurance Act), the “Housing Performance...
1. “Building Standard Act: Earthquake Resistance Standards” – Safeguarding Human Life
The earthquake resistance standards set by the Building Standard Act were made stricter following the revision of the Act on June 1, 1981. The standards prior to this date are referred to as the old earthquake resistance standards, while those after this date are known as the new earthquake resistance standards. 1. Old Earthquake Resistance Standards:Buildings are designed to withstand an earthquake of JMA seismic scale 5+ without collapsing. 2. New Earthquake Resistance Standards:Buildings a...
2. “Housing Quality Assurance Act: Seismic Grade”
The “Housing Performance Labeling System” based on the “Housing Quality Assurance Promotion Act (Housing Quality Assurance Act)” enforced in 2000, provides a seismic grade. This grade evaluates the quake-resistance performance of a house on three levels based on two indices: “damage prevention” and “prevention of collapse, etc.” The higher the grade, the better the quake-resistance performance. 1. Damage Prevention:This refers to a seismic performance level that can withstand an earthquake th...
Earthquake Resistant Structure
This is the most prevalent structure for detached houses in Japan. All buildings constructed after 1981 must comply with the New Anti-seismic Structure Standard, which requires buildings to have an earthquake resistance structure. This structure allows the main building structures, such as posts, walls, and floors, to absorb seismic motions. Buildings can be categorized into Rigid Structure (constructed rigidly to prevent collapse) and Flexible Structure (where the main structural parts bow f...
Vibration Control Structure
To minimize seismic motion, damping walls that absorb seismic energy are built within the structure. Vibration Control structures can be categorized into the Active type, which uses energy such as electricity, and the Passive type, which uses physical forces. Compared to earthquake-resistant structures, Vibration Control Structure structures can reduce seismic intensity by 70-80%.
Seismic Isolation Structure
This structure is commonly used for high-rise buildings as part of their foundation. It places quake-absorbing devices (isolators) such as laminated rubber that blocks seismic motions from reaching the building. Quake-absorbing devices include laminated rubber, lead, springs, dampers, ball bearings, etc. Furthermore, newly-invented construction methods use a combination of these materials. Seismic isolation structure can reduce seismic intensity down anywhere from ⅓ to ⅕ (less than half) when...
Wooden Structure
Wood is the primary material used in these buildings. In this structure, posts and beams serve as the core parts of a building. Many detached houses in Japan are made of wood.
Steel Structure
This refers to buildings primarily using steel materials in their framework. Steel structures are especially suitable for large buildings.
Reinforced Concrete Structure
Building frameworks outfitted with RC (Reinforced Concrete) structure utilize concrete with iron reinforcing bars inside. RC structure takes advantage of both reinforcing bars as well as a steel frame. With Reinforced Concrete structure, steel-made “reinforcing bars” with tolerance against stretching forces, strengthen the “concrete” which resists the compressive forces of the building’s weight.
The risk of earthquake damage varies depending on the ground, the shape of the land, the density of buildings, and other factors. In Tokyo, high-risk areas are located on the ground and classified as alluvial plains or lowland valleys such as fan-shaped lands, natural levee zones, deltas, and are distributed throughout the old downtown area along t...
In conclusion, Japan’s commitment to seismic resilience is evident in its stringent building standards and innovative architectural practices. From the evolution of building laws and regulations to the different types of earthquake-resistant structures, understanding these aspects is crucial when considering a property in Japan. However, always con...
People also ask
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Mar 11, 2011 · Japanese buildings tend to be much stiffer and stouter than similar structures in earthquake-prone areas in California as well, said Mr. Moehle, the Berkeley engineer: Japan’s building code ...
Aug 31, 2015 · These Century-Old Stone “Tsunami Stones” Dot Japan’s Coastline. “Remember the calamity of the great tsunamis. Do not build any homes below this point.”. T.KISHIMOTO, via Wikimedia ...
Feb 13, 2023 · Japanese earthquake-resistant buildings are a result of meticulous planning and innovation. For instance, the seismic isolation bearings used in many Japanese buildings allow for horizontal movement during earthquakes, significantly reducing structural stress. This feature, alongside reinforced concrete frames, enhances the stability and safety ...
Aug 30, 2023 · Takashi Hosoda was in a Tokyo skyscraper when the 9.0 magnitude quake struck on March 11, 2011, but the trained architect was "not particularly worried" as modern Japanese buildings are designed ...
