Damage Based Life of Heritage Structures in Seismic Environment: A Case Study on Golkonda Fort

Abstract

The earthquake resistant design of structures according to the existing design philosophy aims to ensure that during their lifetime, the structures resist the maximum possible earthquake without collapse. This philosophy ignores the fact that for the allowable damage at the end of the design life, it is necessary to account for the seismicity of the area in a comprehensive manner i.e., in terms of magnitudes with proper spatial distributions around the site. It is also necessary to estimate damage due to each of these events and also cumulative damage till date. Such a procedure is proposed in the paper and it is applied to heritage structures which stand for longer duration compared to ordinary buildings. As a case study, the proposed methodology is used to evaluate damage to Golkonda Fort located in Zone II according to IS 1893-2002. Proposed approach is based on the estimation of Power spectral density function (PSDF) of earthquakes already occurred and then estimation of damage to the structure during each of these events. Golkonda Fort is modeled using Applied Element Method (AEM). Pushover analysis of the AEM model is also carried out. The damage computed from the proposed approach is plotted on the fragility curve obtained from the push over analysis for comparison.