A CRITICAL REVIEW ON BASE ISOLATION TECHNIQUES FOR ITS APPLICATION AS EARTH QUAKE RESISTANT BUILDINGS WITH PARTICULAR NEED/ADHERENCE IN EASTERN UTTAR PRADESH

An Earthquake is a natural phenomenon which produces surface waves ultimately causing the vibration of the ground and structures standing on it. Depending on the characteristics of these vibrations the ground may develop cracks, fissures and settlements ultimately resulting ground movement and sometimes proves violent and damages of structures at a very large scale , though earthquake itself is not a disaster. Complete protection of a building due to generation of earthquake waves poses unique challenges in the form of protection of more vertica l sensitive non - structural components ,mitigation of total uplift tension demand generated by overturning forces in slender members and shifting or sliding of the superstructure .For the prevention of buildings and other civil engineering structures from t he damaging effect of earthquake ground shaking ,base isolation is a widely adopted techniques all over the world. This technique consists of shifting the natural period of the structure to the long period range by placing horizontally flexible isolation d evices at the base of the structure to physically decouple it from the ground. This allows the superstructure to remain elastic or nearly elastic following a design level event and minimize the likelihood damage to the civil engineering structures. The dec rease of acceleration and drift in str uctures through base isolation devices makes it one of the most effective strategies operational performances following a large and infrequent earthquake. There are three major types commonly used bearings as isolated devices namely elastomeric bearings (ru bber), rollers and ball bearings , slider bearing (curved, pendulum & flat) and also four types of dampers , i.e . steel, oil ,lead and friction dampers with disc springs are the essential component of a base isolation s ystem. This paper not only summarizes the base isolation techniques, reviews of the current practices and past researches but also need/adherence of these techniques by analyzing the earthquake data of the seven prominent cities/districts of the eastern Ut tar Pradesh. This has been achieved by evaluating the each city/district by existing civil engineering structures of cultural / historical / archaeological importance, existing & pace of growth of high rise buildings, depth of alluvial soil over the soil/ rock , geological, geographical and topographical features and earthquake magnitude.