Duration and sustained amplitude adjusted response spectra – RSx and Da spectra

Nenad Bijelic, Ting Lin, & Gregory Deierlein

In Preparation 2018, SCEC Contribution #8042

Spectral acceleration, spectral shape and significant duration are well recognized as simple yet valuable predictors of structural response. However, in certain instances they may overlook specific features of waveforms that are potentially damaging to structures, such as the sustained amplitude and number of long period cycles of motions associated with surface waves in deep sedimentary basins. In this study, we propose a method for modification of response spectra to account for loading duration effects using the so called sustained amplitude adjusted response spectra, or RSx spectra in short. In addition, we extend the concept of significant duration to be period dependent by introduction of the notion of significant duration spectra, or Da spectra. The RSx and Da spectra retain the simplicity of computation as well as predictability of conventionally used intensity measures while bringing in additional important information about ground motions. Following the introduction of these novel intensity measures, we investigate the properties of RSx and Da spectra for different types of ground motions. In particular, we examine pulse-like motions, spectrally equivalent long and short duration ground motion sets as well as spectrum- and duration-equivalent basin and non-basin ground motion sets. Case studies highlighting the utility of RSx and Da spectra as intensity measures are discussed.

Citation
Bijelic, N., Lin, T., & Deierlein, G. (2018). Duration and sustained amplitude adjusted response spectra – RSx and Da spectra. Earthquake Spectra, (in preparation).

Related Projects & Working Groups
Ground Motion Simulation Validation (GMSV) Technical Activity Group (TAG), Earthquake Engineering Implementation Interface (EEII)