STREAMLINING SEISMIC RISK ASSESSMENT OF EXISTING BUILDINGS

Seismic vulnerability assessment is starting point to any earthquake disaster mitigation programme. With situation of limited resources available and huge investment in seismic risk reduction exercise, prioritization is important. Again, all existing buildings are not weak to be retrofitted or demolished. The reduction of seismic disaster cannot be achieved unless there is good understanding of what is vulnerable to seismic hazards and to which extent. In this paper, a critical study of analytical techniques used in seismic strength evaluation has been presented. The social, economic, and political issues have been discussed with technical aspects, as these are also important in disaster mitigation programmes. The main emphasis is on analytical approaches used and propounded by researchers and practitioners in this field. Methods from linear static procedures that yield in simplified equivalent static lateral load to nonlinear dynamic and stochastic analyses have been used. Upgradation in computing facilities and tools has affected evaluation process the most. The paper seeks for a balance between simplified methods, which yield in overtly conservative results, and complex nonlinear analyses, which are cumbersome and more expert-oriented. Furthermore, seismic vulnerability assessment techniques have been categorized. Various aspects like economic and socio-politico-legal environment, purposes, performance objectives, and other factors have been considered and a strategy has been laid down for selection of analytical tools.