Paper Number 25 Ground motion records for time-history analysis of URM buildings in New Zealand – The North Island

Conference ABSTRACT: The New Zealand Standard for Structural Design Actions, NZS 1170.5:2004, defines a criterion for selecting ground motion records for time-history analysis based on similarity between the seismological signature of earthquakes used for the analysis and those that are expected to be encountered at a given location. However, as most structural designers are not familiar with the specific details of the probabilistic seismic hazard model used to determine the design spectra, further information is currently required before designers can readily select appropriate earthquake records. The objective of the study reported here was to integrate the seismologist’s and the engineer’s specialist knowledge, and to develop a method of selecting the best set of records for different locations considering the hazard level for each location and the seismological characteristic of the expected ground motions. For this purpose, New Zealand has been divided into several seismological hazard zones based on the mapping of the Hazard Factor presented in NZS 1170.5:2004, and the fault mechanism. Furthermore, a suite of records is proposed for use when conducting time-history analysis of existing New Zealand unreinforced masonry (URM) buildings, satisfying the Standard requirements. Recommendations are presented for selecting the records to be used in each zone. Preliminary results are presented for the North Island of New Zealand. A similar proposal for the South Island is still under study. 1