Recommendations for the revision of the approach for seismic design of parts and components in New Zealand design standards

This work makes recommendations for revision of the design provisions for the seismic demands on non- structural elements, parts and components in the New Zealand seismic loading standard. The proposed approach seeks to incorporate new and international knowledge of the factors affecting seismic demands on non-structural elements, but also maintaining simplicity to facilitate adoption. The most significant changes include new expressions for the influence of floor height and building nonlinear response on floor acceleration demands; the amplification of demands on flexible parts due to dynamic amplification associated with the response of structural modes; and potential reductions in part strength requirements by permitting nonlinear part response. The proposed revisions are supported by data from instrumented buildings, numerical modelling and experimental testing. Comparisons between the recommended and existing NZS 1170.5 approaches are presented that show that the proposed approach will lead to reduced design actions in many cases and increased loads in others. Greater demands are prescribed for flexible parts with limited ductile capacity and some parts at the serviceability limit state design level. Conversely, design forces reduce for rigid parts; parts and components on lower levels of buildings; ductile flexible parts; parts in ductile buildings at the ultimate limit state design; and parts with long periods. Finally, the proposed approach is compared with the most recent updates to the code design approaches in Europe and the United States to provide an international context of the state of the art.