Earthquake Safe Construction Tips and Guidelines

• By constructing houses and public buildings safe, 80% to 90% of loss can be reduced. Because

  Disaster risk = Hazard * Vulnerability.

• If Vulnerability is reduced, risk of disaster will decrease.
• Prediction of earthquake only saves human losses not economic losses due to collapse.
• Most of earthquake occurs in ocean.
• Earthquake of Magnitude 6 evolves energy that is equal to 1 Hiroshima atomic bomb.
• Magnitude 7 ==> 100x Energy evolved = 1 Hiroshima atomic bomb.
• Magnitude 8 ==> 100 x 100 Hiroshima atomic bomb.
• Earth is not consistent but its made up of plates.
  • Each moves independently.
  • Plates are called tectonic plates.
  • Earthquake occur due to movement of tectonic plates and their head on collision.

Focus:

• Deep in earth crust. 5 to 6 - 70 to 80 km depth.
• More depth, less will be disaster as more is absorbed inside.
• Projection of focus on earth surface is called epicentre.
• Equivalent Energy is transferred through waves causing vibrations in structure.
• Foundation also moves to and fro. If foundation is made stable, structure will be safe. For example if beams are provided on foundation and structure moves on the beams.
• Walls and Columns are the most important by Earthquake point of view.
• About 1500 tones of steel can be saved in a 60 storey building due to only one level difference of seismic zone.
• 90% of economy losses and 90% of human losses are due to the collapse of buildings.
• Earthquake resistant building is one which does not collapse even if it has irreparable cracks.

Design span of buildings

• Nuclear power plants-> 2500 years.
• Dams and Bridges-> 500 years.
• Houses-> 50 years.
• Not even small cracks should occur in Nuclear power plants because implications are very high i:e, life safety levels are not common in each type of structure.
• 2% of total cost can save a building from earthquake.

Dhajji: Timber frames and bracing. To make earthquake resistant mortar take 1 bag of cement + 3 wheel barrows of sand. The mortar should be used within 1 hr.

• Rectangular or square shaped buildings are good in earthquake resistance.
• Building openings should be well distributed and less.