Ground motion processing in rocking structures

Recorded ground motions require filtering and baseline correction to remove noise that results in unrealistic velocity and displacement time histories.The effect of ground motion processing is well studied for elastic and inelastic oscillators; however, it has not been studied for the rocking oscillator.The behavior of the rocking oscillator is used to describe a wide range of systems; such as masonry structures, unanchored equipment, and ancient Greco Roman and Chinese temples.This paper investigates the effect of ground motion processing on the response of the rocking oscillator.Different types of digital ground motions (pulse like and non pulse like) and different processing schemes and scheme parameter values are presented to illustrate this effect on the displacement spectra for planar rocking blocks.Based on the results of this paper, on a single ground motion basis, ground motion processing has an effect on the rocking spectra which is basically similar to the elastic oscillator.However, when treating the problem in a statistical way (by comparing the statistics of the response to sets of ground motions, not to a single ground motion -as seismic design typically requires), the effect is significantly reduced.In fact, as long as the system is not close to overturning (failure), the rocking spectra only loosely depend on the processing scheme.