https://bulletin.nzsee.org.nz/index.php/bnzsee/issue/feed Bulletin of the New Zealand Society for Earthquake Engineering 2020-04-03T15:20:12+13:00 Rajesh Dhakal rajesh.dhakal@canterbury.ac.nz Open Journal Systems <p>Bulletin of the New Zealand Society for Earthquake Engineering</p> https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1158 Liquefaction assessment of reclaimed land at Centreport, Wellington 2020-04-03T15:15:21+13:00 Riwaj Dhakal ribu.dhakal@pg.canterbury.ac.nz Misko Cubrinovski misko.cubrinovski@canterbury.ac.nz Jonathan Bray jonbray@berkeley.edu Christopher de la Torre christopher.delatorre@pg.canterbury.ac.nz <p>Observations of liquefaction-induced damage at the port of Wellington (CentrePort) provide an opportunity to evaluate the applicability of state-of-the-practice liquefaction evaluation methodologies on reclaimed land. This study focuses on the application of widely used simplified liquefaction assessment methods on the end-dumped gravelly fills and hydraulically-placed silty and sandy fills at CentrePort for the 2013 Cook Strait, 2013 Lake Grassmere, and 2016 Kaikōura earthquakes. Liquefaction assessment of the gravel reclamation poses several challenges due to its large percentage of gravel-sized particles making it difficult to obtain high-quality in situ data. The hydraulic fills at CentrePort are also of significant interest as they relate to a range of issues in the simplified engineering assessment around effects of fines and their plasticity on the liquefaction resistance. Following the 2016 Kaikōura earthquake, subsurface explorations were performed which included 121 Cone Penetration Tests (CPTs). Results of CPT-based liquefaction triggering and post-liquefaction reconsolidation settlement assessments using state-of-the-practice procedures are discussed and compared with observed liquefaction manifestation and settlements.</p> 2020-03-01T00:00:00+13:00 Copyright (c) https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1160 Seismic capacity of RC frame buildings with masonry infill damaged by past earthquakes 2020-04-03T15:18:06+13:00 Hamood Alwashali hamood@rcl.archi.tohoku.ac.jp Md. Shafiul Islam shafiul@rcl.archi.tohoku.ac.jp Debasish Sen dsendip@rcl.archi.tohoku.ac.jp Jonathan Monical jmonica@purdue.edu Masaki Maeda maeda@rcl.archi.tohoku.ac.jp <p>Many of the buildings which experienced damage in recent earthquakes such as the 2015 Nepal Earthquake were reinforced concrete (RC) frame buildings with unreinforced masonry infill walls. This study proposes a simplified procedure to estimate the in-plane seismic capacity of masonry infilled RC frame buildings based on concepts of the Japanese seismic evaluation standard (JBDPA, [1]). The correlation of seismic capacity and observed damage obtained using a database of 370 existing RC frame buildings with masonry infill that experienced earthquakes in Taiwan, Ecuador and Nepal is investigated. The Is index, which represents the seismic capacity of buildings in the Japanese standard, showed good correlation with the observed damage and proved to be effective as a simple method to estimate seismic capacity. The method was then applied to 103 existing buildings in Bangladesh that have not experienced a major earthquake recently. The results emphasize the necessity for urgent seismic evaluation and retrofitting of buildings in Bangladesh.</p> 2020-03-01T00:00:00+13:00 Copyright (c) https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1161 Seismic hazard estimation in stable continental regions 2020-04-03T15:19:31+13:00 Trevor I. Allen trevor.allen@ga.gov.au <p>Damaging earthquakes in Australia and other regions characterised by low seismicity are considered low probability but high consequence events. Uncertainties in modelling earthquake occurrence rates and ground motions for damaging earthquakes in these regions pose unique challenges to forecasting seismic hazard, including the use of this information as a reliable benchmark to improve seismic safety within our communities. Key challenges for assessing seismic hazards in these regions are explored, including: the completeness and continuity of earthquake catalogues; the identification and characterisation of neotectonic faults; the difficulties in characterising earthquake ground motions; the uncertainties in earthquake source modelling, and; the use of modern earthquake hazard information to support the development of future building provisions.</p> <p>Geoscience Australia recently released its 2018 National Seismic Hazard Assessment (NSHA18). Results from the NSHA18 indicate significantly lower seismic hazard across almost all Australian localities at the 1/500 annual exceedance probability level relative to the factors adopted for the current Australian Standard <em>AS1170.4–</em><em>2007</em> <em>(R2018)</em>. These new hazard estimates have challenged notions of seismic hazard in Australia in terms of the recurrence of damaging ground motions. This raises the question of whether current practices in probabilistic seismic hazard analysis (PSHA) deliver the outcomes required to protect communities and infrastructure assets in low-seismicity regions, such as Australia. This manuscript explores a range of measures that could be undertaken to update and modernise the Australian earthquake loading standard, in the context of these modern seismic hazard estimates, including the use of alternate ground-motion exceedance probabilities for assigning seismic demands for ordinary-use structures.</p> <p>The estimation of seismic hazard at any location is an uncertain science, particularly in low-seismicity regions. However, as our knowledge of the physical characteristics of earthquakes improve, our estimates of the hazard will converge more closely to the actual – but unknowable – (time independent) hazard. Understanding the uncertainties in the estimation of seismic hazard is also of key importance, and new software and approaches allow hazard modellers to better understand and quantify this uncertainty. It is therefore prudent to regularly update the estimates of the seismic demands in our building codes using the best available evidence-based methods and models.</p> 2020-03-01T00:00:00+13:00 Copyright (c) https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1162 Quantifying the effects of epoxy repair of reinforced concrete plastic hinges 2020-04-03T15:20:12+13:00 Kai J. Marder kmar702@aucklanduni.ac.nz Kenneth J Elwood k.elwood@auckland.ac.nz Christopher J. Motter kmar702@aucklanduni.ac.nz G. Charles Clifton c.clifton@auckland.ac.nz <p>Modern reinforced concrete structures are typically designed to form plastic hinges during strong earthquakes. In post-earthquake situations, repair of moderate plastic hinging damage can be undertaken by filling the crack system with epoxy resin and reconstituting spalled cover concrete. This study uses available experimental test data, including three large-scale ductile beams tested by the authors, to investigate the effects of epoxy repair on the structural behaviour of plastic hinges, with a focus on beam elements. Factors that have been neglected in past studies, including the effects of residual deformations at the time of repair, are given special attention. It is found that epoxy-repaired plastic hinges can exhibit different behaviour from identical undamaged components in terms of stiffness, strength, deformation capacity, and axial elongation. Potential explanations for the observed differences in behaviour are given, and recommendations are made for how these differences can be quantified in order to relate the expected response of an epoxy-repaired plastic hinge to the response that would be calculated for an identical undamaged component.</p> 2020-03-01T00:00:00+13:00 Copyright (c)