Earthquakes

Earthquakes

Outline

• —  What is Earthquake
• —  Types of Seismic Waves
• —  Effects of Earthquakes
• —  Site Selection
• —  Building Construction Materials
• —  Building Planning | Earthquake Resistant Buildings
• —  Earthquake Resistant Techniques
• —  Summary and Conclusion

What is Earthquake?

Earthquake is a sudden tremor or movement of the earth’s crust, which originate naturally at or below the surface. It is the result of a sudden release of energy in the Earth’s crust that creates seismic waves.

Types of Seismic Waves

1. Primary waves Or P waves Or Push waves
2. Secondary waves or S waves or Shear waves
3. Surface waves
4. L waves and Rayleigh Waves

General Effects of Earthquakes

• Ground Shaking
• Soil failures
• Surface Fault rupture
• Tidal Waves (Tsunamis)

What must we do..??

1. Site selection
2. Building Construction Materials for Earthquake Resistance

1. Masonry
2. Concrete

iii.      Steel

1. Building Planning

1. Size of buildings
2. Horizontal Layout of buildings

iii.      Projections and Overhangs

1. Adjacency of Buildings
2. Heavy mass at the top buildings
3. Avoid long walls

1. Earthquake bands and vertical reinforcement

1. Earthquake bands in Timber
2. Earthquake Bands in RC

Summary and Conclusions

• The weight and rigidity of a structure must be uniformly and symmetrically distributed to the plane of symmetry passing through the centre of gravity.
• The proportionality requirements must be met by the building dimensions i.e. the length and height of the building should not be too great.
• The structure must be light, as practicable and have its centre of gravity as low as possible.
• Desirable tough, light and elastic material be used which have uniform properties.
• In the vertical and horizontal planes the load carrying elements must be coupled to form closed contours.
• The foundations of earthquake resistant buildings must be firm and have enough depth.

Power Point Presentation has been embedded below for better understanding.