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Novel Use of Rubber as "Seismic Bearing" Offers Disaster Prevention Strategy for Phils
by Joeven C. Calasagsag - Tuesday, 26 July 2011, 09:45 AM
Department of Agriculture; July 24, 2011

The novel use of natural rubber as a semi-intelligent “seismic bearing” offers a crucial disaster prevention strategy for the Philippines which is situated in an earthquake-prone belt within the Pacific Ring of Fire.

The Department of Agriculture-Bureau of Agricultural Research (DA-BAR), which has been investing on rubber research and development, has collaborated with the Malaysian Rubber Board (MRB) and the Philippine Rubber Industry Association (PRIA) on exploring potential application of seismic bearing locally.

With the severe destruction of lives and properties in Japan arising from an earthquake and tsunami last March, many countries are now considering the use natural rubber seismic bearings to protect buildings from earthquakes.

. More than 10,000 structures worldwide—including those in the United States, China, Japan, Taiwan, Italy, New Zealand, India, Malaysia, and Indonesia- have used rubber seismic bearings. Some of these buildings have already withstood real earthquakes especially the 1994 Northridgeearthquake in Los Angeles and the 1995 Kobe earthquake in Japan.

This innovative use of rubber in disaster prevention may further enhance renewed interest in the growing of rubber and its product diversification, according to BAR Director Nicomedes P. Eleazar.

“We have the potential to become a big producer of this industrial crop which will generate jobs in rural farms,” said Eleazar.

Nuclear reactors in Japan are now being planned to be put under rubber bearings, according to Dr. Kamarudin Ab-Malek, chief executive officer of MRB’s research center in London. The risk of a tsunami is also making authorities consider putting nuclear reactors on a higher plane to prevent these from tsunami waves.

“I’m sure on the basis of what happened in Japan, similar problems can affect Philippines and other countries, so governments must take measures to ensure that structures are protected,” said Kamarudin.

Buildings with rubber seismic bearings can save significantly by up to 20 percent since construction will no longer need more reinforcement through bigger beams and numerous columns.

Priority buildings where these disaster-preventing rubber bearings may be installed are hospitals, with all their expensive equipment and life-saving functions, and schools.

Natural rubber seismic bearings are considered semi-intelligent as these have been proven to effectively isolate buildings from vibrations brought about by earthquakes where energy waves travel through the earth.

“Under normal conditions, it’s stiff so the building will not move. But when an earthquake comes, rubber automatically becomes soft. It can isolate vibration from the structure to protect it and its content. When the earthquake goes away, it becomes stiff again,” said Kamarudin.

MRB and the International Rubber Research and Development Board (IRRDB) through Dr. Abdul Aziz Kadir went last July 14 and 15 on a mission to the Philippines. That was to orient and potentially partner with civil and structural engineers, local government units, Department of Public Works and Highways and DA on the local use of seismic bearings.

As a pilot work, IRRDB and MRB have made arrangements to use rubber seismic bearings in the construction of the house in Davao City of Jerry Gil Murao of the JDM88 Agroventures Co.

“This could possibly serve as a model for the effectiveness of natural rubber as seismic bearing in the Mindanao Region,” said BAR Rubber Coordinator Rudy L. Galang.

DA-BAR aims to open more farming opportunities in rubber whose market price in the world market has been very attractive at $4,000-5,000 per metric ton (MT) for semi-processed rubber.

At present, there is an estimated 130,000 hectares of land in the country planted with rubber. Expansion of rubber plantations should enable Philippines to expand its market as the world demand for natural rubber was previously estimated to reach to 12.4 million metric tons (MT) by 2020.

Rubber is also eyed as an erosion control, reforestation, and environmental preservation crop as it is biodegradable and is not petroleum-based, unlike synthetic rubbers.

Malaysia, the world’s largest producer of natural rubber-based latex gloves and threads, has long developed natural rubber seismic bearings through MRB.

Kamarudin said MRB’s facility has capability for testing rubber bearings on three components. These are compressive strength to determine if the bearing can support the weight of the building; shear stiffness, a test whether the bearing has the right stiffness in order to perform well in an earthquake; and damping value to ensure that a bearing will only move at a certain displacement in an earthquake.

Manufacturers of rubber bearings in Malaysia give up to a 50-year warranty on the bearings. An existing building may also be retrofitted with rubber bearings as installation may be done in a portion of the building each time.

The first building sitting on rubber bearings called the Law and Justice Center was first constructed in 1985 in Bernardino, California.

However, Malaysia’s first rubber laboratory in London was put up as early as in 1938 to find more applications of rubber in engineering. In 1966, MRB installed rubber bearings on the Albany Court, a building on St. James Park underground train station in London, to prevent vibration in the building caused by the train.

“Train causes high frequency vibration, but we can isolate that with rubber bearings. We prevented vibration by the train from going up to the building. Earthquake is also a vibration problem, but it is a low frequency vibration,” said Ab-Malek.

The MRB has two laboratories, one in its research center in London, the other in Kuala Lumber, Malaysia. Both collaborate with the University of California in Berkeley.

The Pacific Ring of Fire is a horseshoe-shaped imaginary chain of volcanic and earthquake-prone cou ntries in the Pacific Ocean’s basin from Java to Sumatra through the Himalayas, the Mediterranean, and into theAtlantic.[ ### (BAR)]

For inquiries, please call: Mr. Rudy Galang 0916 -200-7331, 920-0227

Source: Novel Use of Rubber as "Seismic Bearing" Offers Disaster Prevention Strategy for Phils

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