Bulletin of the New Zealand Society for Earthquake Engineering https://bulletin.nzsee.org.nz/index.php/bnzsee <p>Bulletin of the New Zealand Society for Earthquake Engineering</p> en-US <ol> <li>You warrant that you have the authority to act as the agent of all the authors of this article for the purpose of entering into this agreement.</li> <li>You hereby grant a <a href="https://creativecommons.org/licenses/by/4.0" target="_blank" rel="noopener">Creative Commons Attribution (CC-BY) license</a> in the article to the general public.</li> <li>You agree to require that a citation to the original publication of the article in the Bulletin of the New Zealand Society for Earthquake Engineering be included in any attribution statement satisfying the attribution requirement of the Creative Commons license of paragraph 2.</li> <li>You retain ownership of all rights under copyright in all versions of the article, and all rights not expressly granted in this agreement.</li> <li>To the extent that any edits made by the publisher to make the article suitable for publication in the journal amount to copyrightable works of authorship, the publisher hereby assigns all right, title, and interest in such edits to you. 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You agree to indemnify the publisher against any claim or action alleging facts which, if true, constitute a breach of any of the foregoing warranties or other provisions of this agreement, as well as against any related damages, losses, liabilities, and expenses incurred by the publisher.</li> </ol> </li> <li>This is the entire agreement between you and the publisher, and it may be modified only in writing. It will be governed by the laws of New Zealand. It will bind and benefit our respective assigns and successors in interest, including your heirs.</li> </ol> rajesh.dhakal@canterbury.ac.nz (Rajesh Dhakal) reagan.c@canterbury.ac.nz (Reagan Chandramohan) Thu, 01 Sep 2022 08:48:18 +1200 OJS http://blogs.law.harvard.edu/tech/rss 60 System overstrength factor induced by interaction between structural reinforced concrete walls, floors and gravity frames: Analytical formulation https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1495 <p class="Summary">In multi-storey structural wall buildings, the structural walls are required to resist additional shear force due to their interactions with the floors and gravity-resisting system, which is not fully catered for in current seismic design provisions and assessment guidelines. This paper scrutinizes the mechanics of the interaction between structural reinforced concrete (RC) structural walls, floors and gravity frames in multi-storey RC structural wall buildings during elastic and nonlinear response phases. It also investigates the implications of this interaction on design of multi-story RC wall buildings. Generic expressions are derived to predict the drift and rotation profiles of multi-storey RC wall buildings. Then, a simple hand calculation method is developed to estimate the system (moment) overstrength of multi-storey RC wall buildings due to system (wall-floor-frames) interaction. The proposed method is applied to a prototype building with different slab dimensions and stiffness, and verified by comparing with the system overstrength factor obtained using finite element analysis. The simplified method estimates, and the nonlinear finite element analyses results agree, that a system overstrength factor of 1.7 can be used to account for the 3D interaction between the structural walls, floors and gravity frames in design and assessment of typical ductile RC wall buildings.</p> Reza E. Sedgh, Rajesh P. Dhakal, Chin-Long Lee, Athol Carr Copyright (c) 2022 Reza E. Sedgh, Rajesh P. Dhakal, Chin-Long Lee, Athol Carr https://creativecommons.org/licenses/by/4.0 https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1495 Thu, 01 Sep 2022 00:00:00 +1200 Development of LSN-based pipe repair rate models utilising data from the 2011 Christchurch earthquakes https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1556 <p class="Summary"><span style="letter-spacing: -.05pt;">The Canterbury Earthquake Sequence (CES) adversely impacted built, economic and social environments. This included widespread physical damage to the water supply pipe network in Christchurch, resulting in long service disruptions. The transient and permanent ground deformations generated by the earthquakes in the CES caused a range of pipe damage, particularly in the M<sub>W</sub> 6.2 22 February 2011 and the relatively less damaging M<sub>W</sub> 6.0 13 June 2011 event. Damage to the pipes in both events was largely attributed to liquefaction and lateral spreading effects. Pipes made of ductile material (e.g. PVC, HDPE) sustained lesser damage (and therefore lower repair rates) compared to the pipes made of non-ductile material (e.g. AC, CI). In all cases, the repair rates (number of repairs per kilometre) typically increased with increasing liquefaction severity.</span></p> <p class="Summary">Utilising the pipe repair dataset and Liquefaction Severity Number (LSN) maps generated from extensive geotechnical investigation following the CES events, new repair rate prediction models for water pipes subjected to liquefaction effects have been derived and are presented in this paper. Repair data from both earthquakes has been analysed independently and in combination, providing two sets of repair rate functions and different levels of uncertainty. Repair rate functions were first derived from pipes grouped by combination of diameter (i.e. ϕ &lt; 75 mm or ϕ ≥ 75 mm) and material type (i.e. ductile or non-ductile). The models were then refined by adding correction factors for those material types and diameters with sufficient sample length. Correction factors were derived for AC, CI, PVC pipes of diameter ≥75 mm and for MDPE and HDPE80 pipes of diameter &lt;75 mm. Galvanised Iron (GI) pipes performed poorly during the earthquakes, resulting in very high repair rates compared to the other non-ductile pipes of diameter &lt;75 mm damaged in the network; this warranted a separate repair rate model to be developed for this pipe type. The proposed models can be used in risk assessment of water pipe networks; i.e. to estimate the number of pipe repairs from potential liquefaction damage from future earthquakes.</p> Jose Moratalla, Vinod Sadashiva Copyright (c) 2022 Jose Moratalla, Vinod Sadashiva https://creativecommons.org/licenses/by/4.0 https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1556 Thu, 01 Sep 2022 00:00:00 +1200 Seismic performance characterization of fire sprinkler piping systems through shake table testing https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1561 <p>Fire sprinkler systems damaged during earthquakes can compromise building functionality either by loss of fire protection and/or flooding damage. To characterize the seismic behavior of fire sprinkler piping systems, shake table tests were conducted on a piping specimen with features representative of actual practices in New Zealand. The specimen was subjected to a set of motions including recorded floor acceleration response histories of an instrumented building in New Zealand. This paper describes the test setup and the piping specimen, and discusses the seismic response of the specimen to multiple floor motions for different bracing variations. Based on the test results reported in this paper, it can be concluded that bracing segments of piping other than the distribution pipe, such as the branch and arm-over pipes, can considerably affect the seismic demand on the system. Further, the test results confirm that the seismic demands on pipes can be considerably greater if the piping system is in resonance with the input excitation motion.</p> Muhammad Rashid, Rajesh P. Dhakal, Timothy Sullivan, Trevor Yeow Copyright (c) 2022 Muhammad Rashid, Rajesh Dhakal, Timothy Sullivan, Trevor Yeow https://creativecommons.org/licenses/by/4.0 https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1561 Thu, 01 Sep 2022 00:00:00 +1200 Interpretation and evaluation of NZS1170.5 2016 provisions for seismic ratcheting https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1622 <p>During seismic events, some structures have a tendency to ratchet and displace more in one direction than in the opposite direction after yielding, resulting in larger peak and residual displacements. Provisions to define the tendency for seismic ratcheting and the resulting displacement amplification are provided in the 2016 amendments of NZS1170.5. This paper presents some insight into the factors causing ratcheting, along with interpretation and evaluation of the proposed provisions. Firstly, the mechanics of seismic ratcheting due to dynamic stability, eccentric gravity loads, and unbalanced structural strengths in the back-and-forth directions are discussed. Afterwards, the new provisions were detailed and demonstrated by working through the NZS1170.5 commentary examples. The authors’ interpretation of the provisions is then presented, potential areas of confusion are identified, and wording changes to provide consistency and clarity are proposed. Finally, the displacement amplification factors provided in the 2016 amendments were evaluated using results of an independent study on single-degree-of-freedom reinforced concrete bridge columns subjected to eccentric gravity loading. It was found that the displacement amplification method proposed was reasonable, except when columns designed with a high ductility factor or which exhibit inelastic bilinear response had a significant tendency for ratcheting.</p> Khaled Saif, Trevor Yeow, Chin-Long Lee, Gregory MacRae Copyright (c) 2022 https://creativecommons.org/licenses/by/4.0 https://bulletin.nzsee.org.nz/index.php/bnzsee/article/view/1622 Thu, 01 Sep 2022 00:00:00 +1200