Rizal Philippines
December 19, 2015
NHK feature for J ITEC - building earthquake technology
Japan Seismic Technology
Ever wondered how Japan's skyscraper survived the March 11, 2011 earthquake. Japan sits at 4 tectonic plates constantly rubbing each other that is why earthquakes are of daily occurrence. The most deadly are the 2011 in Tokyo and the 2008 in Kobe. However the Japanese technology and building codes have been constantly improved to cope up with growing menace of deadly earthquakes. The leader in this is Kajima construction company.
It all started in l963 when there was a go ahead for building high rise in Japan
The seismic technology can be divided into two: fitting the new buildings, and retrofit existing buildings from the ground and top. Most of these new technology were developed by Kajima and Professors in the University. Muto and Koburi. Professor Motu's concept are strong yet flexible building. For the first building, using this theory Kasumageshi building, he developed special steel structures that were light (with holes in between, like the frames of airplanes) and were constructed with great precision.
Koburi on the other hand, developed technologies that would lessen the effect of earthquakes, and this was called Active Mass Device. (AMD) and these were massive a la pendulum concrete blocks that hang on cables to counteract the forces of earthquake. It was first used in l989
Then there was the TMD, total mass device that can be installed on rooftops of existing buildings. It was observed that towers continued to sway uncontrollably for 12 minutes after the earthquake stopped. Thus to lessen this massive dampers made of 300 tons concrete blocks swayed, vs the swaying motion of earthquakes, Lab tests showed this to be effective.
How about low rise building.: Kajima uses the Base Isolation technology. Rubber dampers that had steel plates sandwhiches in between absorved the movement when placed between ground and column. This was effective in Red Cross Hospital that did not suffer damages and thus could be used at once as disaster coordinating center
This was used to retrofit the Tokyo station. The pine piles numbering 6000 in all were replaced by 300 of these dampers. The project took five years to complete but made the station earthquake ready.
Can we do this in the Phil. All that we are ready to do are earthquake drills? Are building owners not preparing their buildings for the disaster? How are our building officials taking this challenge?
If Japan can do this, cant we?
Air Suspension System
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