Seismic Collapse Risk of Stone Masonry Buildings in the Indian Himalayas
摘要
Conventionally, seismic hazard at a site is represented by a uniform hazard spectrum (UHS), which represents the seismic hazard in terms of spectral ordinates corresponding to a fixed probability of exceedance at all periods of vibration. Alternatively, a hazard curve can be developed for a site corresponding to each spectral period, which provides the probability of exceedance of different amplitudes of spectral ordinates. The hazard curve can be used for the estimation of the collapse risk of a structure in a given life span. Accordingly, if a structure is designed using a standard procedure to yield a standard fragility curve, a design response spectrum can be constructed to achieve a targeted collapse risk of the structure in its life span. The obtained spectrum is designated as a risk-targeted response spectrum (RTRS). Thus, RTRS provides design spectral demand to achieve uniform (targeted) collapse risk across all spectral periods. RTRS depends on the targeted risk value and construction type, given the site’s seismic hazard. The focus of this study is constructing RTRS for masonry structures aiming to enhance their service life and achieve the targeted collapse risk, which will help gain better control over their performance. Also, a comparative study of the UHS corresponding to different locations and RTRS for chosen targeted risk for the northern Himalayan region is performed in this paper. Moreover, the risk values for the masonry structures with varying heights of storey and dynamic parameters are also compared, and the obtained values are compared with the targeted risk value.