Analysis for Seismic Retrofitting of Buildings
The Analysis for Seismic Retrofitting of Buildings of reinforced concrete buildings not designed to withstand seismic action is considered. After briefly introducing how seismic action is described for design purposes, methods for assessing the seismic vulnerability of existing buildings are presented. The traditional methods of seismic retrofitting are reviewed and their weak points are identified. Modern methods and philosophies of seismic retrofitting, including base isolation and energy dissipation devices, are reviewed. The
presentation is illustrated by case studies of actual buildings where traditional and innovative retrofitting methods have been applied.
This paper attempts to gather the available information particularly on the nonlinear behaviour, and the various approaches available to evaluate the seismic safety of buildings. It is emphasized that the existing procedure is grossly approximate, and hence improving sections of the approach to high levels of accuracy would not necessarily lead to a better result. The need of the present hour is to see what needs to be done in the Indian context. The basic inputs are earthquake spectrum, nonlinear load-deformation behaviour under monotonic cyclic and random loadings, acceptable levels of damage under various performance levels etc., and these have a lot of grey areas. There needs to be a wider discussion among the researchers to evolve a good standard for use by the profession.