For many applications, the choice and weighting of the GMPEs, including the assigned aleatory uncertainty, are the most critical of the input parameters. Therefore, any seismic hazard assessment should be scrutinised by testing various cases regarding key model components. PSHA results are sensitive to model components/assumptions. Goda, in Handbook of Seismic Risk Analysis and Management of Civil Infrastructure Systems, 2013 1.2.3 Current issues in modern PSHA Probabilistic seismic hazard analysis of civil infrastructure The validity of the seismic hazard model was confirmed by comparing the results with the shaking intensity for the only two return periods (475 and 975 years) publicly available for the Kyrgyz Republic from the Kyrgyzstan Disaster Risk Data Platform at. Soil conditions that can potentially amplify the shaking intensity at the school sites were obtained from the Global slope-based Vs30, the time-averaged shear wave velocity to 30 m depth, by the U.S. Annual exceedance rates for different levels of PGA and Sa (0.2) were obtained by running a full earthquake hazard analysis in the country using the OpenQuake software 2 (see Fig. 9.7). For each school site identified by a latitude and longitude, the seismic hazard is evaluated for the peak ground accelerations (PGA) and the 5 percent damped spectral acceleration at a period of vibration of 0.2 s, Sa (0.2). Seismic hazard is not uniformly distributed across the territory of the Kyrgyz Republic. Reader may refer to Section 2.4.2 of ASCE 41-13 ( ASCE, 2013) and also Section 5.2.1.1 for more details. This is based on the geologic, seismologic, and soil characteristics associated with the building site. In addition to the above-mentioned procedures, it is also possible to specify the acceleration response spectra with the use of site-specific procedure. Values for BSE-2E are not required to be greater than those obtained for BSE-2N. It is computed using values from approved 5%/50-year maximum-direction spectral response acceleration contour maps ( S S and S 1). It is considered as a seismic hazard with a 5% probability of exceedance in 50 years (lower than the BSE-2N). Values for BSE-1E are not required to be greater than those achieved for BSE-1N. It is computed using values from approved 20%/50-year maximum-direction spectral response acceleration contour maps ( S S and S 1). It is equivalent to a seismic hazard with a 20% probability of exceedance in 50 years (lower than the BSE-1N). Therefore, it is estimated using two-thirds of the S S and S 1 values obtained for the BSE-2N seismic hazard level. Defined as two-thirds of the BSE-2N useful for the BPON standards. Therefore, it is computed using values of S S and S 1 taken from the MCE R spectral response acceleration contour maps ( ASCE, 2017a). It is equivalent to MCE R to be used for the BPON standards. Different seismic hazard level can be defined ( ASCE, 2013) and relative 5% damped acceleration response spectrum for short period ( T s = 0.2 second), S S, and long period ( T 1 = 1 second), S 1, in the maximum direction of horizontal response, can be determined as follows: This hazard may depend upon the location of the building with respect to faults, the regional and site-specific geologic and geotechnical features, and the specified seismic hazard levels. Seismic hazard due to ground shaking can be defined as acceleration response spectra or ground motion acceleration histories specified based upon a probabilistic or a deterministic analysis ( ASCE, 2013).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |