Evaluation of Ground motion Record Scaling and Selection Methods for Seismic Design and Assessment of Structures

Amplitude scaling and selection of ground-motion records are frequently used tools to obtain a group of accelerograms suitable for structural performance assessment for a given hazard level. To provide a suitable set of records to be used in nonlinear dynamic analysis either to estimate median structural response or to predict its full probability distribution, “n” scaled ground motions that best match with target spectrum are selected. Common concerns related with this approach are the use of appropriate definition of target spectrum according to the objective of nonlinear dynamic analysis and the number of required recordings, “n”, that yield unbiased structural response. This study uses scenario event spectrum, conditional mean spectrum, and conditional spectrum as alternative targets with 7, 11 and 15 records. Additionally, the adequate level of spectral match between ground-motion records and the target is also a critical issue as it could lead to biased results. This study uses a modified goodness-of-fit measure and investigates corresponding threshold levels to classify records that yield unbiased structural response