Vulnerability and Damage Analysis of Existing Buildings

The assessment of seismic performance of buildings under future earthquakes is becomingan important problem in earthquake engineering. Some important buildings are considerably old and therefore their strengths and ductilities are less than strength and ductility demands. Such buildings must be strengthened to resist future earthquakes. First the structural model is developed and then based on seismic hazard and seismic risk analysis or code quantities, the design (or control) parameters are determined. The next step consists of defining the damage indices. Then the nonlinear dynamic analysis is carried out. Finally based on numerical results one can determine the amount and how of strengthening. In this paper some damage indices are reviewed and then a formulation is presented for considering the importance of columns and lower stories failure. As an example, a ten story building in Tehran is analyzed.