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Web crippling behaviour of cold-formed steel channel sections having elongated edge-stiffened web holes under interior-two-flange loading condition
(Elsevier, 2023-11-01) Wang, Wei; Roy, Krishanu; Fang, Zhiyuan (Arthur); Beulah Gnana Ananthi, G.; Lim, James Boon Piang
In the past decade, cold-formed steel (CFS) channel sections having circular edge-stiffened web holes have been developed in New Zealand. Such edge-stiffened holes increase the strength of the CFS channel sections, compared to an equivalent section having unstiffened holes, while still allowing full service integration. In the case of web crippling, previous research has found that use of edge-stiffened holes almost results in the same strength of an equivalent channel-section having a plain web. Such circular edge-stiffened web holes can now be extended to elongated edge-stiffened web holes. However, for such elongated holes, no experimental tests have been reported in the literature. In this paper, a numerical investigation was carried out, and non-linear finite element (FE) analyses were used to investigate the web crippling behaviour of CFS channel sections having edge-stiffened web holes under the interior-two-flange (ITF) loading condition. The cases of both flange fastened and flange unfastened were considered. The FE models were validated against test results of sections having circular edge-stiffened web holes; good agreement in terms of the load–displacement curves and deformed shapes was shown. Using the validated FE models, a parametric study was carried out on CFS channel sections having elongated un-stiffened and edge-stiffened web holes, comprising 1,227 finite element analyses (FEA) results. Compared to sections having a plain web, for the case of an elongated opening, without any edge-stiffener, having an aspect ratio of two and three, the average reduction in web crippling strength was 39% and 49%, respectively. However, for an edge-stiffened hole, the reduction in the web crippling strength was reduced to only 2% and 16%, respectively. Finally, the design equations in the form of the web crippling reduction factor (Rp) and the equations based on the direct strength method (DSM) for CFS sections with elongated web holes were proposed.
Enclosures and Oceans
(Routledge, 2025) McCormack, Fiona; Foley, Paul; Silver, Jennifer
Enclosure is a concept used to describe how spaces, previously outside the reach of capitalist discipline, become subsumed to market logics, primarily through processes of privatisation. Beginning in Europe in the late Middle Ages, enclosure movements sliced up common fields, pastures and wasteland into private holdings, expropriating peasants from their land while leaving them ‘free’ to sell their labour on the emergent market economy (Hanna 1990; Polanyi 2001). This is a transformation of human and non-human lives and, crucially, of the socioecological relations that had worked to sustain this intersection. Notions of improvement, efficiency and modernization underpin enclosure drives, ideologies carried to the colonies to justify the removal of indigenous peoples from ancestral territories; a violence enacted through both military and legal means (Thompson 1991).
Gender affirming or disenfranchised grief? Considering death rights in Aotearoa New Zealand
(Routledge, 2026) Schott, Gareth R.; Doyle, Benjamin Kauri; Grant, Wairehu; Lykke, Nina; Mehrabi, Tara; Radomska, Marietta
The pre-colonial Māori world treated variety in gender and sexual expression in an accepting and encompassing manner (Te Awekotuku, et al. 2005; Aspin and Hutchings 2007). Among the many negative health implications of colonialism for Māori, it is acknowledged that “tangata takatāpui [LGBTQ+ people] moved from a social and cultural situation where minority stress was simply not a factor … to one where it has become a key force in the negative health outcomes they experience” (Stevens 2016, 15). This chapter acknowledges how death can generate ‘ownership battles’ over the deceased, resulting in members of the LGBTQ+ community, receiving final farewells that have been unrepresentative, or a reversal of the freedom to self-determine identity. We reflect on how death rights for takatāpui individuals is a human and cultural right in the context of Aotearoa New Zealand. In doing so, it calls for an extension of the principles of the Māori health framework Te Pae Māhutonga currently being applied in advocation of gender affirming health research and practice conducted in Aotearoa New Zealand (Veale et al. 2019). This chapter reconsiders how we understand ‘templated’ rituals and death rites by introducing the challenges of a more responsive and gender affirming parting.
Web crippling design of cold-formed stainless steel channels under interior-two-flange loading condition using deep belief network
(Elsevier, 2023-01) Fang, Zhiyuan (Arthur); Roy, Krishanu; Padiyara, Sujith; Chen, Boshan; Raftery, Gary M.; Lim, James Boon Piang
This research presents a deep-learning framework, namely a deep belief network (DBN), for analyzing the interior-two-flange web crippling performance of cold-formed stainless steel channels with centered and offset web holes. An elastoplastic finite element (FE) model, validated using 101 experimental results which were previously reported in the literature, generates a total of 43,200 data points for training the DBN. When compared to a total of 54 experimental results published in the literature, the DBN predictions were shown to be approximately 10% more conservative. Using the same large training data, the developed DBN model outperformed the Backpropagation Neural Network (a typical shallow artificial neural network) and the PaddlePaddle-based linear regression model. A parametric analysis was then performed using the DBN predictions to explore the effect of section size, web holes and bearing length. Design equations for (reduced) web crippling strength are proposed for the cold-formed stainless steel perforated channels, and the feasibility of the proposed equations was assessed by the conducted reliability analysis.
Numerical investigation of cold-formed steel channels with edge-stiffened and unstiffened elongated web holes under shear
(Elsevier BV, 2024) Chandramohan, Dinesh Lakshmanan; Roy, Krishanu; Fang, Zhiyuan (Arthur); Beulah Gnana Ananthi, G.; Lim, James Boon Piang
Over the past decade, cold-formed steel (CFS) channel sections having edge-stiffened circular web holes have been developed in New Zealand. Such edge-stiffened holes increase the strength of the CFS channel sections, compared to an equivalent section having unstiffened web holes, while still allowing full building service integration. In the case of shear, previous research has found that the use of edge-stiffened web holes significantly improves the shear strength of such channel sections. However, no studies are available in the literature investigating the shear strength of CFS channel sections with edge-stiffened elongated web holes. The issue is addressed herein. Non-linear finite element (FE) analyses are used to investigate the shear strength of CFS channel sections with a shear span aspect ratio of 2.0. The FE models were validated against the experimental test results of sections having unstiffened elongated web holes and edge-stiffened circular web holes; good agreement in terms of the load-displacement curves and failure behaviour was shown. Using the validated FE models, a parametric study was conducted, comprising 2124 finite element analyses (FEA) results. The parametric results were then compared to the design predictions of the American Iron and Steel Institute (AISI 2016), and Australia/New Zealand Standards (AS/NZS 2018) and Wanniarchchi et al. (2017) for unstiffened elongated web holes, showing that the design predictions are unconservative in comparison results. Moreover, the direct strength method (DSM) approach of Pham et al. (2020a and 2023) provides conservative results for channels with unstiffened elongated web holes. It was also found that the design equations proposed by Chen et al. (2022) for edge-stiffened circular web holes were unconservative in predicting the shear strength of channels having edge-stiffened elongated web holes. Therefore, design equations in the form of a shear reduction factor and a modified DSM approach for CFS channel sections having unstiffened and edge-stiffened elongated web holes were proposed. Finally, a reliability analysis was carried out to ensure that the proposed equations are reliable to predict the shear strength of CFS channel sections with edge-stiffened and unstiffened web holes.