Rocking Spectrum for Cylindrical Structures Subjected to Bidirectional Pulse-Like Ground Motions

Abstract

In recent years, cylindrical structures free to rock have been exploited in practical engineering. However, their seismic response in three dimensions (3D), greatly sensitive to the parameters that define it, is difficult and time-consuming to predict. To this end, this study focuses on developing a rocking spectrum, an efficient graphical tool linking seismic rocking response to structural parameters, for seismic response prediction and performance-based seismic design of cylindrical structures. The development of the rocking spectrum is based on the numerical rocking response of 2500 idealized rigid cylinders excited by 100 sets of synthetic bidirectional pulse-like ground motions. The minimum Redundancy Maximum Relevance (mRMR) algorithm is first employed to reveal that the rocking response is more related to ground acceleration, ground velocity, and ground displacement when the response is small (close to uplift), intermediate, and large (close to overturning), respectively. Following these relations, the support vector machine (SVM) algorithm is employed to develop the rocking spectrum. The obtained rocking spectrum can reliably predict the rocking response of cylinders subjected to the synthetic pulse-like ground motions. The applicability of the spectrum is also discussed for as-recorded pulse-like ground motions.