Stability Analysis of Rocking Soil-Structure Systems Subjected to Near- Fault Pulses

The overturning potential of rocking soil-structure systems subjected to near-fault pulses is investigated in this paper. An extensive parametric study is conducted, including medium-tohigh- rise buildings with different aspect ratios based on shallow raft foundation allowed to uplift considering the effects of nonlinear soil-structure interaction. The considered parameters are (i) ground motion characteristics, (ii) structural properties of the superstructure, and (iii) foundation design parameters. Mathematical directivity and fling pulses are used as input ground motion. The superstructure is assumed to predominantly showcase first-mode characteristics. Two-dimensional overturning spectra of buildings of various geometrical, as well as dynamic characteristics, are derived. Evidently, the prevalent pulse period (Tp) is a key parameter governing the rocking response of the system. It is also observed that fling pulses are more destructive than directivity pulses of the same magnitude with respect to overturning potential. On the other hand, the lower frequency parameter (p) of the more large-size buildings is a quantity that indicates higher safety margins against toppling with respect to small-size buildings of the same aspect ratio.