An earthquake is a sudden and rapid shaking of Earth's surface caused due to the movement of tectonic plates floating on the molten rock below the surface of earth. It causes vibrations of structures and induce inertial forces on them. As a result structure may collapse resulting into loss of property and lives. Earthquakes do not kill people, vulnerable buildings do so. Hence, there is need of designing earthquake resistant buildings, especially in the earthquake prone areas. The earthquake resistance of buildings may be increased by taking some precautions and measures in site selections, building planning and building constructions which are explained below:
Improving Earthquake Resistance of Small Buildings
- Avoid buildings in sloping grounds with different column heights.
- Provide simple and symmetric geometry in plan.
- Avoid too many doors and windows close to each other.
- Windows should be kept at same level.
- In sloping roof with span greater than 6m, use trusses instead of rafters.
- Building with four sided sloping roof is stronger than the one with two sided sloping, since gable walls collapse early.
- Restrict the projections of chajja and balcony to maximum of 1m. For larger projections, use beams and columns.
- Provide following RC bands:
- Plinth Band
- Lintel Band
- Sill Band
- Roof Band
- Gable Band
- Offering retrofitting solutions to vulnerable structures ensures their resilience and safety is enhanced.
Improving Earthquake Resistance of High Rise Buildings
- Provide shear walls evenly throughout the building.
- Provide base isolation
- Provide seismic dampers
- Provide seismic gap in between neighbouring structures.
- The reinforcement within structural elements should ensure adequate strength and ductility.