In-plane response of two-story structures to near-fault ground motion

• Linear and non-linear responses of a two-story structure excited by near-source motions are investigated.
• The differential-motion effects amplify the first-story drifts 3.0–4.0 times relative to the synchronous horizontal ground motion.
• Horizontal ground motion contributes about two thirds of the total drift, and the vertical and rocking motions about one third.
• For the nonlinear system, the effects of vertical and rocking motions become more significant for the second-story drifts.

Linear and non-linear responses of a two-story structural model excited by near-source fault-normal pulse and fault-parallel displacement are investigated. For the considered linear system, the multi-component differential-motion effects amplify the first-story drifts 3.0–4.0 times relative to the excitation by synchronous horizontal ground motion only. The contribution of horizontal differential ground motion to the total drift is about two thirds, and the contribution of vertical and rocking differential ground motions is about one third. For the considered nonlinear system, the effects of vertical and rocking differential ground motions become more significant for the second-story drifts. The horizontal differential ground motion amplifies the first-story drifts, but the simultaneous action of horizontal, vertical, and rocking differential ground motions can amplify the first- and second-story drifts by more than 2.0 times relative to the drifts computed for uniform horizontal ground motion only.