Why a Building Twists In your childhood, you must have sat on a rope swing – a wooden cradle tied with coir ropes to the sturdy branch of an old tree. The more modern versions of these swings can be seen today in the children’s parks in urban areas; they have a plastic cradle tied(…)
Ground Shaking
SEISMIC DESIGN PHILOSOPHY FOR BUILDINGS
The Earthquake Problem Severity of ground shaking at a given location during an earthquake can be minor, moderate and strong. Relatively speaking, minor shaking occurs frequently, moderate shaking occasionally and strong shaking rarely. For instance, on average annually about 800 earthquakes of magnitude 5.0-5.9 occur in the world while the number is only about 18(…)
HOW THE GROUND SHAKES DURING EARTHQUAKE
Seismic Waves Large strain energy released during an earthquake travels as seismic waves in all directions through the Earth’s layers, reflecting and refracting at each interface. These waves are of two types – body waves and surface waves; the latter are restricted to near the Earth’s surface (Figure 1). Body waves consist of Primary Waves(…)