Haiti Earthquake 2010

Every year, earthquakes take the lives of thousands of people , and destroy property worth billions. The 2010 Haiti Earthquake killed over 1,50,000 people and destroyed entire cities and villages. Designing Earthquake Resistant Structures is indispensable. It is imperative that structures are designed to resist earthquake forces, in order to reduce the loss of life. The science of Earthquake Engineering and Structural Design has improved tremendously, and thus, today, we can design safe structures which can safely withstand earthquakes of reasonable magnitude.

Index of all posts on Earthquake Resistant Structures

1. Design Earthquake Resistant Buildings | Engineering Tips
2. Earthquakes and Natural Calamities
3. Types of Seismic Waves
4. Hazardous Effects of Earthquakes
5. Effect of Earthquakes on Structures
6. Building Stiffness and Flexibility | Earthquake Engineering
7. Inertial Forces in a Structure
8. Effects of Deformations in Structures
9. Horizontal and Vertical Shaking of a Structure
10. Flow of Inertia Forces to Foundations
11. How Earthquakes affect Reinforced Concrete Buildings
12. Building Planning | Earthquake Resistant Buildings
13. Earthquake Resistant Structures by Planning and Design Approach
14. Design Philosophy of Earthquake Resistant Designs
15. Building Construction Materials for Earthquake Resistance
16. Concept of Earthquake Resistant Engineering
17. Seismic Base Isolation Technique for Building Earthquake Resistance
18. Energy Dissipation Devices for Earthquake Resistant Building Design
19. Active Control Devices for Earthquake Resistance

There are two basic types of seismic waves, and they travel at different speeds through earth. The faster p waves and the slower s waves.

Primary or push waves or P waves

Primary Waves

These are longitudinal in nature like sound waves. The velocity of P waves is highest about 5.4 km/s and depends on the density of the rock and resistance to compression. P waves can pass through liquids also.

Secondary or shake waves or S waves

Secondary Waves

These are transverse in nature like light waves. The velocity of S waves is about 3.3 km/s. The velocity of S waves depends upon density of the rock and resistance to distortion. The S waves cannot pass through liquids.

Surface waves

When the P-waves and S-waves travel on the surface, they are known as surface waves

L waves and Rayleig Waves

These are also transverse in nature like S waves. The velocity of S waves is about 3.0 km/s. L waves are formed due to dashing of P and S waves against the solid crust of the earth. These are the waves, which we feel in the form of earthquake. These waves are responsible for the destruction of the life and property. Height of L waves is about 30cm and distance between two successive crests is about 10 m. and increase in their amplitude beyond only 1/16 of an inch is capable of causing lot of destruction. Due to high velocity of these waves, the civil engineering structures vibrate and a typical sound due to passage of energy is heard.