Developments in performance-based seismic design and assessment approaches have emphasized the importance of considering residual deformations. Recent investigations have also led to a proposed direct displacement-based design (DDBD) approach which includes an explicit consideration of the expected residual deformations as an integral part of the design process. Having estimated the expected residual deformations in a structure, engineers are faced with the problem of reducing them to meet the targeted performance levels under pre-defined seismic hazard levels. Previous studies have identified the post-yield stiffness as a primary factor influencing the magnitude of residual deformations in single degree of freedom and multiple degree of freedom structures. In this paper, a series of simple approaches to increase the post-yield stiffness of traditional framed and braced systems for the purpose of reducing residual deformations are investigated. These methods do not utilize recentring post-tensioned technology. This contribution addresses the feasibility of altering the lateral post-yield stiffness of structural systems by: (i) using different reinforcement materials with beneficial features in their stress-strain behaviour; (ii) re-designing the section geometry and properties of primary seismic-resisting elements; and (iii) introducing a secondary elastic frame to act in parallel with the primary system. The efficiency of each of these techniques is investigated through monotonic and cyclic moment-curvature and non-linear time-history analyses. Of these approaches the design and introduction of an elastic secondary system was found to be most effective and consistent in reducing residual deformations. A simplilfied design approach for achieving the desired increase of a system's post-yield stiffness is also presented. Copyright © 2007 John Wiley & Sons, Ltd

This paper summarizes developed guidance on the utilization of earthquake-induced ground motion simulations for engineering practice. Attention is given to the necessary verification, validation and utilization documentation in order for confidence in the predictive capability of simulated motions to be established. The construct of a ground motion simulation validation matrix is developed for assessing the appropriateness of a particular suite of simulated ground motions from the perspective of region-to-site-specific application and for different specific engineering systems. Appropriate validation metrics and “pass” criteria, the consideration of modeling uncertainties, and limitations associated with a relative lack of validation data are also addressed. An example is utilized in order to demonstrate the application of the guidance. This document is intended to be bidirectional in the sense that it provides guidance for earthquake engineers on the appropriateness of a suite of ground motion simulations for utilization in a site-specific context, as well as ground motion simulators to understand the context in which their results will be utilized.

This report outlines the observations of an NZSEE team of practitioners and researchers who travelled to the Kumamoto Prefecture of Japan on a reconnaissance visit following the April 2016 earthquakes. The observations presented in this report are focussed on the performance of reinforced concrete (RC) buildings throughout Kumamoto Prefecture. It was found overall that modern RC buildings performed well, with patterns of damage which highlighted a philosophy of designing stiffer buildings with less of an emphasis on ductile behaviour. To explore this important difference in design practice, the Japanese Building Standard Law (BSL) is summarised and compared with standard New Zealand seismic design practices and evaluation methods.

Impulse ground motions are applied to single story structures with different in-plane wall strength and stiffness, rotational inertia, and out-of-plane wall stiffness to obtain the dynamic response considering torsion. A simple hand method to evaluate the impulse response is developed. It is shown that the median increase in response of the critical component considering torsion from many earthquake records is similar to that from impulse records. Using this information, a simple design methodology is proposed which enables the likely earthquake response of critical elements considering torsion to be obtained from building analyses not considering torsion. A design example is also provided.

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