Hazard, Vulnerability, Risk Assessment of Himachal Pradesh

Abstract

In recent past due to rapid growth of Indian cities, there is a tremendous increase on housing industry, especially in seismic Zone-IV & V. As most of these constructions are without earthquake resistant measures, the built environment in these zones has been found seismically vulnerable. Since Indian cities are built with varied varieties of building typologies, comprising of poorly designed and less maintained ones, the seismic safety of these constructions became the most challenging task. Seismic vulnerability is a measure of the seismic strength or capacity of a structure, hence it is found to be the main component of seismic risk assessment. Detailed seismic vulnerability evaluation is a technically complex and expensive procedure and can only be performed on a limited number of buildings. It is therefore very important to use simpler procedures that can help to rapidly evaluate the vulnerability profile of different types of buildings, so that the more complex evaluation procedures can be limited to the most critical buildings. In the present study for 9099 buildings of different housing typologies in Himachal Pradesh had been surveyed. Out of which approximately 50 buildings are studied in detailed for which, vulnerability assessment is carried out. In this report the main focus is on state of damage with respect to peak ground acceleration and RVS score. The same analysis is done for all five typologies of structures (Reinforced Concrete, Brick Masonry, Stone Masonry, Rammed Earth and Hybrid). For this purpose, numerical modeling using SAP and AEM are considered. The methodology of the numerical models is discussed in the following sections. Using energy approach, damage of buildings are evaluated both in X and Y directions. From the analysis, it is concluded that the rammed earth buildings are brittle when subjected to seismic forces on it. The buildings are collapsed in moderate to high seismic zones as per Indian seismic standards. The RVS score of above buildings are from 82 to 93 of 0.36 g.