Abstract:
Earthquakes, unlike other natural disasters, leave no time for mass evacuation of people thus result in a huge loss of lives and property. The developments that took place over the century in the fields of seismology and Earthquake resistant design envisage the understanding and effort put in by the yesteryear researchers. Development of Probabilistic methods to estimate the ground motions have been underway in many countries. In India too, much efforts are made to develop a probabilistic estimation of ground motions. However, a complete Probability based development of Seismic zoning map for Indian region is yet to become a reality.
Capacity Based Design, the first design philosophy to rationally consider the ductility of the structure, provides a detailed sequence of designing the members for effective energy dissipation and guides in assigning a predefined failure mechanism. However, the uncertainties in estimating the exact seismic capacity of the structure, particularly its ductility have forced the research community to develop a new design philosophy called Performance Based or Displacement Based design in which the displacement response of a structure is related with strain-based limit states. Since, the strain and deformation give a better indication of the level of damage in the structure, different levels of performance objectives are fixed based on the strain and displacement limits of the structure and its elements.
