This standard is intended for earthquake resistant design of normal structures. It is applicable to buildings, elevated structures, bridges, concrete, embankments and retaining wall. It has been endeavored to ensure that, as far as possible, structures are able to respond, without structural damage to shocks of moderate intensities and without total collapse to shocks of heavy intensities. It takes into account:
a) Seismic zone factor. (Fo)
b) Importance factor, to account for the varying degrees of importance for various structures. (I)
c) The coefficient of Flexibility for design of multi- storeyed building is given in form of a curve with respect to period of buildings.
d) Performance factor depending on the structural framing system and brittleness or ductility of construction.
e) Intensity of shock due to earthquake.
f) The seismic zone map, the object of this map is to classify area of the country into five seismic zones.
Earthquake cause random motion of ground, which can be resolved in any three mutually perpendicular directions. This motion causes the structure to vibrate. The vibration intensity of ground expected at any location depends upon the magnitude of earthquake, the depth of focus, distance from epicenter and the strata on which the structure stands. There might be cases in which structure have less importance factor and relatively small structure for which no analysis need be made. There is Clause in code which gives permissible increase in allowable bearing pressure or resistance of soils.
