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.
In seismic-prone regions, construction projects face elevated vulnerability risks that extend beyond structural design. While technical evaluations are common, few frameworks integrate managerial, human, and logistical dimensions into seismic risk assessment. This study addresses this gap by applying the Analytic Hierarchy Process (AHP) to evaluate seismic vulnerability using a structured multi-criteria decision-making model. Key parameters—including human resources, materials, supply logistics, and organizational practices—are weighted through expert input and analysed in three Algerian case studies across various seismic zones. Findings reveal that human and organizational factors significantly influence overall vulnerability. The study offers a replicable framework and highlights opportunities for enhancing decision-making through AI integration.
This study examines the impact of gusset plate design on the collapse risk of two buckling-restrained braced frame (BRBF) buildings, incorporating superX and diagonal brace configurations. Nonlinear dynamic analysis shows that the gusset plate axial compressive strength is, on average, 30% lower than the design strength estimated by NZS-3404, indicating that the current design approach may be non-conservative. This study explores three alternative design methods: (i) NZS-3404 design with modifications (NZS-3404-revised), (ii) Court-Patience (CP) method, and (iii) Notional load yield line (NLYL) method. On average, the gusset plate axial compressive strength obtained from dynamic analysis aligns closely with the design strengths predicted by the NZS-3404-revised and CP methods. The NLYL method explicitly accounts for the reduced strength of mid-span gusset plates in super-X and chevron-configured BRBFs. The gusset plate strengths from dynamic analysis are approximately 30% greater than those estimated by the NLYL method, demonstrating that this approach is sufficiently conservative and therefore recommended for design. Within the limited range of brace and gusset plate configurations studied, the collapse risk is reduced by a factor of 3.5 when the NLYL method is used instead of the NZS-3404 method.
This short manuscript describes how three different schools of thought, combining observation, pragmatism, physics, and judgment, have arrived at strikingly similar approaches to proportion RC building structures that can sustain intense earthquake demands without incurring excessive structural and non-structural damage. The examined traditions, which can be traced back to Japan, the University of Illinois at Urbana-Champaign, and Chile, were shaped by independent calibration processes. Yet they all share a common idea: structural robustness is crucial to reduce building earthquake damage. The success of this simple idea has been demonstrated repeatedly in the field. For that reason, New Zealand engineering students, at the very least, should be made aware of these practices, especially considering that the local tradition is radically different.
This paper explores the influence of ground improvement on building seismic demands through parametric site response analyses of low-to-mid-rise buildings supported on mat foundations. A set of soil profiles, containing liquefiable strata, and two building archetypes are analysed using two-dimensional finite element models, both with and without improved zones underneath the buildings. The densification/stiffness of the improved zone and the depth of the improvement is varied as part of the parametric study. The seismic demand on the buildings and foundations for the unimproved and improved sites is assessed. The results show that ground improvement effectively reduces foundation displacements but often increases base shear and inter-storey drift demands. Under total stress conditions, amplified structural seismic demands show a good correlation with increases in shear-wave velocity of the improved ground. However, when liquefiable soil behaviour is modelled, the ratio of the depth of improvement to the depth of the liquefiable stratum (Zi/Zsoft,liq) is a more reliable predictor of seismic demands. When Zi/Zsoft,liq = 0.50, foundation subsidence relative to the adjacent unimproved ground is limited to less than 50 mm in most cases, and rocking drift remains below 0.5%, provided that bearing pressures do not exceed 80 kPa. This improved depth ratio is identified as a good threshold for limiting the potential for damage. However, beyond this threshold, the ability of the building to sustain repairable damage after an ULS earthquake relies on its capacity to accommodate increased flexural drift caused by soil–foundation–structure interaction effects. The trends identified in this study offer valuable insights into how ground improvement influences seismic demand on buildings.
