Save Structures from Damage
Left: Illustration of the Urgent Earthquake Detection and Alarm System (UrEDAS) for Shinkansen lines
Right: The Tohoku Shinkansen: No accidents during the Great East Japan Earthquake. All lines restored and running by end of April. (Photo: Railman Photo Office)
The major earthquake that struck the Pacific Coast of East Japan on March 11, 2011 claimed the lives of over 15,000 people and destroyed or partially damaged many buildings. More than 90% of the fatalities and most of the structural damage, however, were caused by the massive tsunami that followed. Devastation as a result of the earthquake itself was surprisingly limited considering its magnitude of 9.0 on the Richter scale, due to an array of technologies developed in response to natural disasters.
Take the trains, for example. In Fukushima, Miyagi, and Iwate Prefectures, which were struck hardest by the quake, five Shinkansen trains operating at 270km/hour did not derail; in fact, all were able to come safely to an emergency stop. The UrEDAS system — which detects an earthquake’s small seismic waves prior to the arrival of larger waves and automatically cuts the power to bring trains to a stop — functioned perfectly.
Earthquake-Resistant Construction Standards Updated 30 Years AgoSendai, the largest city of Miyagi Prefecture and the Tohoku region, was hit by strong tremors measuring over intensity six on the Japan Meteorological Agency (JMA) seismic intensity scale. Although many roofing tiles of old houses were dislodged, very few buildings actually toppled or collapsed.
The low instances of severe structural damage may be due to the fact that most modern buildings have been built to meet the New Earthquake-Resistant Construction Standards, which were revised in 1981. They were devised to ensure that structures are able to withstand earthquakes measuring up to intensity seven, the highest reading on the JMA scale. Thus, structures equipped with thicker beams, posts, as well as more braces and rebar that were previously required managed to survive the massive quake.
Apple Towers Sendai (photo: APA Group) proved the effectiveness of seismic isolation construction (illustration).
From Earthquake Resistance to Seismic IsolationEarthquake damage is not limited to collapsing buildings. Tremblors measuring six or more in intensity can send furniture and large interior fixtures falling or flying, crushing people in their path. The threat increases dramatically with height: the higher the floor, the stronger it shakes during a quake, leading to increasingly severe damage in rooms. To mitigate this danger, the construction industry has for the past 15 years been researching “seismic isolation” technologies, whereby structures are decoupled from the base foundation, so that the buildings themselves are not affected by ground tremors. Such construction methods proved to be particularly effective for high-rise buildings during the recent earthquake.
The laminated rubber bearing (left) and sliding seismic isolator (right) are key structural elements to seismic isolation construction.
“Not a lot of objects fell over in our building,” remarks a developer of a 30-story building in Sendai. “In fact, we’ve had residents tell us that they were glad to have chosen to live in an apartment with seismic isolation.” The developer of an 18-story office building echoes this, stating proudly: “Even on the upper floors, no bookshelves toppled over, and nothing fell off of tables. The only damage to speak of were cracks in the interior boards.”
Sendai MT Building remained undamaged during the Great East Japan Earthquake.
The measurement equipment shows that the building experienced as much as 23cm of horizontal displacement. (Photo: Mori Trust Co., Ltd.)
Left: Illustration of the Urgent Earthquake Detection and Alarm System (UrEDAS) for Shinkansen lines
Right: The Tohoku Shinkansen: No accidents during the Great East Japan Earthquake. All lines restored and running by end of April. (Photo: Railman Photo Office)
Right: The Tohoku Shinkansen: No accidents during the Great East Japan Earthquake. All lines restored and running by end of April. (Photo: Railman Photo Office)
The major earthquake that struck the Pacific Coast of East Japan on March 11, 2011 claimed the lives of over 15,000 people and destroyed or partially damaged many buildings. More than 90% of the fatalities and most of the structural damage, however, were caused by the massive tsunami that followed. Devastation as a result of the earthquake itself was surprisingly limited considering its magnitude of 9.0 on the Richter scale, due to an array of technologies developed in response to natural disasters.
Take the trains, for example. In Fukushima, Miyagi, and Iwate Prefectures, which were struck hardest by the quake, five Shinkansen trains operating at 270km/hour did not derail; in fact, all were able to come safely to an emergency stop. The UrEDAS system — which detects an earthquake’s small seismic waves prior to the arrival of larger waves and automatically cuts the power to bring trains to a stop — functioned perfectly.
Earthquake-Resistant Construction Standards Updated 30 Years AgoSendai, the largest city of Miyagi Prefecture and the Tohoku region, was hit by strong tremors measuring over intensity six on the Japan Meteorological Agency (JMA) seismic intensity scale. Although many roofing tiles of old houses were dislodged, very few buildings actually toppled or collapsed.
The low instances of severe structural damage may be due to the fact that most modern buildings have been built to meet the New Earthquake-Resistant Construction Standards, which were revised in 1981. They were devised to ensure that structures are able to withstand earthquakes measuring up to intensity seven, the highest reading on the JMA scale. Thus, structures equipped with thicker beams, posts, as well as more braces and rebar that were previously required managed to survive the massive quake.
Apple Towers Sendai (photo: APA Group) proved the effectiveness of seismic isolation construction (illustration).
From Earthquake Resistance to Seismic IsolationEarthquake damage is not limited to collapsing buildings. Tremblors measuring six or more in intensity can send furniture and large interior fixtures falling or flying, crushing people in their path. The threat increases dramatically with height: the higher the floor, the stronger it shakes during a quake, leading to increasingly severe damage in rooms. To mitigate this danger, the construction industry has for the past 15 years been researching “seismic isolation” technologies, whereby structures are decoupled from the base foundation, so that the buildings themselves are not affected by ground tremors. Such construction methods proved to be particularly effective for high-rise buildings during the recent earthquake.
The laminated rubber bearing (left) and sliding seismic isolator (right) are key structural elements to seismic isolation construction.
“Not a lot of objects fell over in our building,” remarks a developer of a 30-story building in Sendai. “In fact, we’ve had residents tell us that they were glad to have chosen to live in an apartment with seismic isolation.” The developer of an 18-story office building echoes this, stating proudly: “Even on the upper floors, no bookshelves toppled over, and nothing fell off of tables. The only damage to speak of were cracks in the interior boards.”
Sendai MT Building remained undamaged during the Great East Japan Earthquake.
The measurement equipment shows that the building experienced as much as 23cm of horizontal displacement. (Photo: Mori Trust Co., Ltd.)
댓글 없음:
댓글 쓰기