Seismic Characterization and Vulnerability of Building Stock in Hilly Regions

Abstract

Because of the limitations posed by the topographic conditions, buildings located on hill slopes have highly irregular configurations in comparison with buildings located on flat terrain. Extensive field surveys were conducted in two test bed cities, Mussoorie and Nainital, situated in the Himalayan state of Uttarakhand in India, in order to develop a comprehensive building stock inventory. Depending on the arrangement and relative levels of foundations, six different structural configurations were identified. A total of 57 different building typologies were identified and classified using alphanumeric string codes, taking into account the building’s structural configuration, number of stories above the uppermost foundation level, predominant material of construction, and floor and roof types. The classification scheme was kept general and thereby applicable to any hilly region. In the later part of this article, seismic fragility of the most commonly found reinforced-concrete moment-resisting frame (RCMRF) building configurations in the Indian Himalayas was investigated using a numerical study. It was observed that the existing building stock in hilly regions is significantly more vulnerable to earthquakes as compared to the flat-terrain counterparts.