title: Numerical investigation of cold-formed steel channels with edge-stiffened and unstiffened elongated web holes under shear

authors: Chandramohan, Dinesh Lakshmanan

subjects: elongated web holes

abstract: 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.

text: Numerical investigation of cold-formed steel channels with edge-stiffened and unstiffened elongated web holes under shear 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.

year: 2024

title: Health invaders in New Zealand primary schools

authors: Burrows, Lisette

subjects: health policy

abstract: Escalating concern over childhood obesity rates, children’s eating habits and their physical activity regimes has fuelled the development of multiple health policies and resources. Many of these are reaching into primary schools, contouring pedagogical opportunities and influencing how young people may come to understand themselves as healthy (or not). In this paper, we map the health policy/resource context in New Zealand emergent over the past two decades, examining the form and content of health messages circulating and their incursions into primary school environments. We also consider the potential effects for teachers and students of enduring health ‘invasions’ in the primary school space.

text: Health invaders in New Zealand primary schools Escalating concern over childhood obesity rates, children’s eating habits and their physical activity regimes has fuelled the development of multiple health policies and resources. Many of these are reaching into primary schools, contouring pedagogical opportunities and influencing how young people may come to understand themselves as healthy (or not). In this paper, we map the health policy/resource context in New Zealand emergent over the past two decades, examining the form and content of health messages circulating and their incursions into primary school environments. We also consider the potential effects for teachers and students of enduring health ‘invasions’ in the primary school space.

year: 2015

title: Level 2 Māori medium programmes: What are the perceptions of parents and students on this form of education?

authors: Hill, Richard Kenneth

subjects: Māori medium

abstract: Māori medium education provides a range of options for families wishing to educate their children through the indigenous language of Aotearoa New Zealand. Level 2 programmes with 51–80% Māori language instruction, can play an important role in supporting students and their Māori language development, yet little is known about these programmes. This project explored the experiences of whānau (families) and students of level 2 Māori medium programmes to gauge the contribution they make to the education of students. It found that this form of education attracts whānau with wide ranging aims and expectations, but offers highly satisfactory educational options for them. However, there are some tensions, particularly in regard to the part they play in lifting students’ Māori language skills. Ensuring graduates of level 2 programmes have a pathway to learn the Māori language beyond primary school was also a cause for concern.

text: Level 2 Māori medium programmes: What are the perceptions of parents and students on this form of education? Māori medium education provides a range of options for families wishing to educate their children through the indigenous language of Aotearoa New Zealand. Level 2 programmes with 51–80% Māori language instruction, can play an important role in supporting students and their Māori language development, yet little is known about these programmes. This project explored the experiences of whānau (families) and students of level 2 Māori medium programmes to gauge the contribution they make to the education of students. It found that this form of education attracts whānau with wide ranging aims and expectations, but offers highly satisfactory educational options for them. However, there are some tensions, particularly in regard to the part they play in lifting students’ Māori language skills. Ensuring graduates of level 2 programmes have a pathway to learn the Māori language beyond primary school was also a cause for concern.

year: 2017