08-13-2012, 01:40 AM
Normalization and scaling accelerograms for nonlinear structural analysis
Shome, Nilesh; Cornell, C. Allin
Earthquake Engineering Research Institute (EERI), Proceedings of 6th U.S. National Conference on Earthquake Engineering, Seattle, WA, May 31 - June 4, 1998, 1998-06, PDF (270 KB)
The paper makes a case for the legitimacy and the benefits of scaling strong ground motion records and investigates how best to do it. In order to study scaling, comparison is made between the statistics of ductility and normalized hysteresis energy (NHE) results for different SDOF and MDOF structures from two sets of 20 recorded ground-motions where each set is chosen from a specific magnitude and distance "bin". "Normalization," defined as scaling of records within a bin to the bin median "intensity" level is examined and several different alternative normalization parameters or "intensity" measures, e.g, normalization to the PGA level, normalization to spectral acceleration at the structure's lowest frequency and different damping levels, frequency-averaged normalization, etc. are compared. Uncritical use of PGA is discouraged especially for low frequency building structures while the normalization to the spectral acceleration at the lowest natural frequency of the structure and at higher damping (typically 5%-20%) is most convenient for practical use and best among the alternatives. The primary advantage of normalization is that it reduces the variance of damage estimation without causing bias, therefore permitting the use of fewer records.
PDF 270 KB | RAR 205 KB
Shome, Nilesh; Cornell, C. Allin
Earthquake Engineering Research Institute (EERI), Proceedings of 6th U.S. National Conference on Earthquake Engineering, Seattle, WA, May 31 - June 4, 1998, 1998-06, PDF (270 KB)
The paper makes a case for the legitimacy and the benefits of scaling strong ground motion records and investigates how best to do it. In order to study scaling, comparison is made between the statistics of ductility and normalized hysteresis energy (NHE) results for different SDOF and MDOF structures from two sets of 20 recorded ground-motions where each set is chosen from a specific magnitude and distance "bin". "Normalization," defined as scaling of records within a bin to the bin median "intensity" level is examined and several different alternative normalization parameters or "intensity" measures, e.g, normalization to the PGA level, normalization to spectral acceleration at the structure's lowest frequency and different damping levels, frequency-averaged normalization, etc. are compared. Uncritical use of PGA is discouraged especially for low frequency building structures while the normalization to the spectral acceleration at the lowest natural frequency of the structure and at higher damping (typically 5%-20%) is most convenient for practical use and best among the alternatives. The primary advantage of normalization is that it reduces the variance of damage estimation without causing bias, therefore permitting the use of fewer records.
PDF 270 KB | RAR 205 KB
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