Comparison of seismic responses using recorded and simulated ground motions for NZS1170.5-based 3D structural analysis

This paper compares the responses of two 3D building models subjected to recorded and simulated ground motions following New Zealand (NZ) code-based ground-motion selection and scaling provisions to examine the applicability of simulated ground motions for use in conventional engineering practice in NZ. The buildings were designed according to NZ building codes and physically constructed in Christchurch prior to the 2010-2011 Canterbury earthquakes. 40 recorded ground motions from the 22 February 2011 Christchurch earthquake, along with previously published simulated ground motions for this event were considered. The seismic responses of the structures are principally quantified via the peak floor acceleration and peak inter-storey drift ratio. The peak floor accelerations of both buildings, and peak drifts of the 13 storey in-plan regular RC wall structure, were statistically consistent; whereas the peak drifts for the seven storey in-plan irregular mixed system are approximately 30% different. Overall, the results indicate a general agreement in seismic demands obtained using the recorded and simulated ground motion ensembles, and hence provide further evidence that state-of-the-art simulated ground motions can be used in code-based structural performance assessments in place of, or in combination with, ensembles of historically recorded ground motions.