Near-Fault Shaking Demands on Short Structures

Near fault earthquake shaking may cause structures to experience inelastic displacement demands which are significantly greater than that expected from design level earthquakes. This paper describes the inelastic demands for elastic-perfectly plastic single-degree-of-freedom oscillators to actual recorded earthquake motions. Inelastic response spectra from sites at known locations relative to the fault are used to quantify the inelastic demands in terms of a relationship between lateral force reduction factor, period and ductility. For medium and long period oscillators the severity of inelastic demand increased as the distance along the fault from the epicenter in the direction of rupture increased. Short period oscillators were relatively unaffected by the near-fault shaking effects.