title: Investigation on shear behaviour and design for aluminium alloy with circular edge stiffened holes with shear span ratio 1

authors: Manoj, Esther Mariya

subjects: cold-formed aluminium

abstract: Cold-formed aluminium (CFA) structural members are increasingly being adopted in engineering applications due to their favourable strength-to-weight ratio, corrosion resistance, recyclability, and long-term durability in harsh environments. A promising application lies in lightweight framing systems, where circular service holes in the web accommodate mechanical, electrical, and plumbing (MEP) installations. However, such openings significantly reduce shear capacity, leading to premature buckling and distortion.
This study investigates the shear behaviour of CFA channel sections with unstiffened and edge-stiffened circular web holes through nonlinear finite element (FE) analysis, validated against experimental results from the literature. The FE models demonstrated strong predictive capability, with mean FEA-to-test ratios of 1.02 for aluminium and 1.07 for cold-formed steel, and low coefficients of variation (<0.06). A comprehensive parametric study is done by simulations evaluated the effects of hole size, stiffener length, section depth, thickness (2.0- 3.5 mm), and alloy grade (H36 and H38). The results showed that unstiffened holes reduced shear capacity by up to 60% (at dw/d1-0.6), while edge stiffeners effectively regained 15-40% of the lost strength. Increasing thickness from 2.0 to 3.5 mm more than doubled shear capacity,and the H38 alloy consistently outperformed H36 due to its higher yield strength.
Comparisons with international design standards ([AISI 2016], [AS/NZS 2018], and [ADM 2015]) revealed that current provisions are conservative for plain webs but underestimate the strengthening contribution of edge stiffeners. To address these shortcomings, new design equations based on a modified Direct Strength Method (DSM) were proposed, incorporating shear reduction factors and elastic buckling coefficients tailored for aluminium members with web perforations. The findings contribute to safer and more efficient design of cold-formed aluminium systems, supporting the integration of perforated channels in modern construction practice.

text: Investigation on shear behaviour and design for aluminium alloy with circular edge stiffened holes with shear span ratio 1 Cold-formed aluminium (CFA) structural members are increasingly being adopted in engineering applications due to their favourable strength-to-weight ratio, corrosion resistance, recyclability, and long-term durability in harsh environments. A promising application lies in lightweight framing systems, where circular service holes in the web accommodate mechanical, electrical, and plumbing (MEP) installations. However, such openings significantly reduce shear capacity, leading to premature buckling and distortion.
This study investigates the shear behaviour of CFA channel sections with unstiffened and edge-stiffened circular web holes through nonlinear finite element (FE) analysis, validated against experimental results from the literature. The FE models demonstrated strong predictive capability, with mean FEA-to-test ratios of 1.02 for aluminium and 1.07 for cold-formed steel, and low coefficients of variation (<0.06). A comprehensive parametric study is done by simulations evaluated the effects of hole size, stiffener length, section depth, thickness (2.0- 3.5 mm), and alloy grade (H36 and H38). The results showed that unstiffened holes reduced shear capacity by up to 60% (at dw/d1-0.6), while edge stiffeners effectively regained 15-40% of the lost strength. Increasing thickness from 2.0 to 3.5 mm more than doubled shear capacity,and the H38 alloy consistently outperformed H36 due to its higher yield strength.
Comparisons with international design standards ([AISI 2016], [AS/NZS 2018], and [ADM 2015]) revealed that current provisions are conservative for plain webs but underestimate the strengthening contribution of edge stiffeners. To address these shortcomings, new design equations based on a modified Direct Strength Method (DSM) were proposed, incorporating shear reduction factors and elastic buckling coefficients tailored for aluminium members with web perforations. The findings contribute to safer and more efficient design of cold-formed aluminium systems, supporting the integration of perforated channels in modern construction practice.

year: 2025

title: The Physical Work Environment in relation to the Physical and Psychological Symptoms of Sick Building Syndrome

authors: Meikle, Sarah Marie

subjects: Sick Building Syndrome

abstract: This study investigated the relationship between perceptions of a poor physical work environment (PWE) and sick building syndrome (SBS), and with various psychological variables that impact organizational productivity. 164 employees working in medium to large office buildings in New Zealand completed an online questionnaire. Overall, the results supported the relationships that were predicted. Ratings of a poor PWE were strongly and positively related to SBS symptoms. Both ratings of a poor PWE and SBS symptoms were positively related to absenteeism, turnover intentions, and continuance commitment; and were negatively related to affective commitment, perceived organizational support, and job satisfaction. SBS mediated the relationship between PWE and most of these variables, except for continuance commitment. Contrary to prior research self-rated job performance was not found to be related to PWE or SBS. The major implications of this research are that it is important for researchers and managers alike to consider the physical aspects of the work environment as well as managerial and interpersonal aspects. This research also showed that New Zealand employees are experiencing SBS symptoms, indicating SBS is just as important for New Zealand organizations as it is for organizations overseas. Further implications of this study, and directions for future research are discussed in the final chapter.

text: The Physical Work Environment in relation to the Physical and Psychological Symptoms of Sick Building Syndrome This study investigated the relationship between perceptions of a poor physical work environment (PWE) and sick building syndrome (SBS), and with various psychological variables that impact organizational productivity. 164 employees working in medium to large office buildings in New Zealand completed an online questionnaire. Overall, the results supported the relationships that were predicted. Ratings of a poor PWE were strongly and positively related to SBS symptoms. Both ratings of a poor PWE and SBS symptoms were positively related to absenteeism, turnover intentions, and continuance commitment; and were negatively related to affective commitment, perceived organizational support, and job satisfaction. SBS mediated the relationship between PWE and most of these variables, except for continuance commitment. Contrary to prior research self-rated job performance was not found to be related to PWE or SBS. The major implications of this research are that it is important for researchers and managers alike to consider the physical aspects of the work environment as well as managerial and interpersonal aspects. This research also showed that New Zealand employees are experiencing SBS symptoms, indicating SBS is just as important for New Zealand organizations as it is for organizations overseas. Further implications of this study, and directions for future research are discussed in the final chapter.

year: 2011

title: The Daldy Mcwilliams ‘Outrage’ of 1879

authors: Hart, Philip

abstract: In the later 1870s, conflicts developed near Paeroa between a small hapu, Ngati Hako, and other hapu over land sales and surveys. In 1879, after some members of Ngati Koi offered to sell the Pukehanga Block, at Rotokohu, between Paeroa and Te Aroha, to the Crown, surveyors were sent to determine the boundaries despite threats of violence from Ngati Hako. These threats became a reality with shots being fired, wounding a surveyor’s assistant, ‘Daldy’ McWilliams, who survived by playing dead. Despite Pakeha fury about a ‘weak’ response, officials reacted cautiously, fearing to provoke a wider conflict. 
Instead of trying to arrest the two men accused of the attempted murder, which would have been difficult, because Ngati Hako claimed their action was justified the Native Minister encouraged senior Hauraki rangatira to convene a rununga to examine their claim. Ngati Hako said that the block of land was theirs, and as previously other land had been surveyed without their permission they had taken this action. The government was criticized for paying advances on a block that had not been through the land court, and the rununga determined that although Ngati Hako had acted wrongfully, their action could be justified. When Ngati Hako refused to hand over the two accused to the authorities, the rununga claimed not to have the power to hand them over; Ngati Hako then constructed two pa to defend themselves.
Such actions provoked much frustration and criticisms of the government amongst Pakeha, but officials who investigated Ngati Hako’s complaints agreed that they had indeed lost land unjustly. Once the owners of a large domain, they had lost their land to the invading Marutuahu, whose slaves they became. When the two accused were arrested in 1882 one was found not guilty and the other was amnestied after eight months in prison because it was believed that, as rangatira, they probably had not fired the shots but had taken the responsibility for the actions of their hapu. As for McWilliams, he received what he considered inadequate compensation.
This ‘outrage’ was the first and only time in Hauraki that a Maori had shot a Pakeha, and the government’s cautious but firm response meant that the ‘peace of Hauraki’, although disturbed for a while, was maintained.

text: The Daldy Mcwilliams ‘Outrage’ of 1879 In the later 1870s, conflicts developed near Paeroa between a small hapu, Ngati Hako, and other hapu over land sales and surveys. In 1879, after some members of Ngati Koi offered to sell the Pukehanga Block, at Rotokohu, between Paeroa and Te Aroha, to the Crown, surveyors were sent to determine the boundaries despite threats of violence from Ngati Hako. These threats became a reality with shots being fired, wounding a surveyor’s assistant, ‘Daldy’ McWilliams, who survived by playing dead. Despite Pakeha fury about a ‘weak’ response, officials reacted cautiously, fearing to provoke a wider conflict. 
Instead of trying to arrest the two men accused of the attempted murder, which would have been difficult, because Ngati Hako claimed their action was justified the Native Minister encouraged senior Hauraki rangatira to convene a rununga to examine their claim. Ngati Hako said that the block of land was theirs, and as previously other land had been surveyed without their permission they had taken this action. The government was criticized for paying advances on a block that had not been through the land court, and the rununga determined that although Ngati Hako had acted wrongfully, their action could be justified. When Ngati Hako refused to hand over the two accused to the authorities, the rununga claimed not to have the power to hand them over; Ngati Hako then constructed two pa to defend themselves.
Such actions provoked much frustration and criticisms of the government amongst Pakeha, but officials who investigated Ngati Hako’s complaints agreed that they had indeed lost land unjustly. Once the owners of a large domain, they had lost their land to the invading Marutuahu, whose slaves they became. When the two accused were arrested in 1882 one was found not guilty and the other was amnestied after eight months in prison because it was believed that, as rangatira, they probably had not fired the shots but had taken the responsibility for the actions of their hapu. As for McWilliams, he received what he considered inadequate compensation.
This ‘outrage’ was the first and only time in Hauraki that a Maori had shot a Pakeha, and the government’s cautious but firm response meant that the ‘peace of Hauraki’, although disturbed for a while, was maintained.

year: 2016