Earthquake Risk and Cooperation: SEISMIC ISOLATION TO MITIGATE EARTHQUAKE IMPACT

EARTHQUAKE DESTRUCTION IN POOR COUNTRIES

"The recent earthquakes have again emphasized the fact that the major loss of life in earthquakes happens when the event occurs in developing countries. Even in relatively moderate earthquakes in areas with poor housing, many people are killed by the collapse of brittle, heavy, unreinforced masonry or poorly constructed concrete buildings. Modern structural control technologies such as active control or energy dissipation devices can do little to alleviate this, but it is possible that seismic isolation could be adapted to improve the seismic resistance of poor housing and other buildings such as schools and hospitals in developing countries". (J.M.Kelly).

RELIEF OR PREVENTION ?

“More effective prevention strategies would save not only tens of billions of dollars, but save tens of thousands of lives. Funds currently spent on intervention and relief could be devoted to enhancing equitable and sustainable development instead, which would further reduce the risk for war and disaster. Building a culture of prevention is not easy. While the costs of prevention have to be paid in the present, its benefits lie in a distant future. Moreover, the benefits are not tangible; they are the disasters that did NOT happen.” (Kofi Annan, UN Secretary-General: “Introduction to Secretary-General’s Annual Report on the Work of the Organization of United Nations, 1999").

SEISMIC ISOLATION

Seismic isolation is a construction method for protecting buildings, in which the building and ground are separated by an isolation system to limit the transmission of vibrations through the building. It reduces the earthquake force and changes it to a slow vibration, so not only the building, but also everything inside is protected.

Seismic isolation provides numerous benefits:

Safety improvement: Damage to not only the building itself but also interior facilities are restricted and gas or water leaks are prevented, as are secondary accidents due to falling furniture and human lives are protected.

Maintenance of function: The function of buildings can be ensured even after a major earthquake and life can continue as normal.

Protection of property: The difficulties of repair, reinforcement, demolition and rebuilding were experienced after the Great Hanshin Earthquake in Japan. Seismic isolation reduces concern.

Improvement of relief: Fear of earthquake can be alleviated and psychological burden is reduced.Evacuation route is secured after an earthquake.

Economic effect of seismic isolation: Considering safety improvements for disaster during an earthquake and reduction of repair costs after an earthquake, seismic isolation can reduce life cycle cost.

Increased flexibility: Earthquake input to building can be considerably reduced while design flexibility is increased. Precast construction method simplifies the whole structure including junctions and reduces weight of members.