School of Future Environments - Huri te Ao

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https://hdl.handle.net/10292/13907

AUT is home to a number of renowned research institutes in architecture and creative technologies. The School of Future Environments - Huri te Ao strong industry partnerships and the unique combination of architecture and creative technologies within one school stimulates interdisciplinary research beyond traditional boundaries.

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A Highly Stretchable Strain-based Sensing Sheet for the Integrated Structural Health Monitoring
(IOP Publishing, 2024-06-28) Zhang;, Hui; Beskhyroun, Sherif
In this study, a flexible strain sensing system that can be applied to full-scale reinforced concrete frame structures is presented. In order to fulfil the criteria for strain detection that are posed by various structural components, the flexible strain gauge is offered in two distinct configurations: one full bridge and one double half bridge. A strain configuration selector is built on the basis of this information. The selector is designed to enable the system to flexibly switch strain modes for measuring axial or bending strain without adjusting the installation location of strain sensors. The first section of this study focuses mostly on elaborating on the methodology behind the development of a flexible strain system. This method was primarily designed with the aim of detecting the abnormalities in the strain field that are brought on by structural damage in order to accomplish the goal of local detection. The creation of a strain configuration selector also enables the conversion between two different strain measures whenever it is necessary without requiring the sensor installation to be moved to a new position, which helps to significantly reduce the amount of cost associated with sensor deployment. The performance of the flexible strain sensing system as well as its sensitivity were evaluated by doing the cyclic load testing on a full-scale RC frame. Both half-bridge and full-bridge strain gauges are installed in the critical components, such as beams and columns. In addition, 14 linear variable displacement transducers (LVDTS) were placed on the RC frame in order to monitor variations in displacement and deformation. The findings of the experiments indicate that the flexible strain sensor exhibits a high degree of sensitivity, and it is therefore suitable for integration into a structural health monitoring (SHM) system for the purpose of tracing the strain caused by localised structural damage. Additionally, it is able to monitor the strain trend on the complete scale of the frame model. In future work, the flexible strain system will be modified and enhanced by using wireless technology for data transmission in order to build a wirelessly integrated structural health monitoring (SHM) system.
A Perspective on Conservation Technologies for Endangered Marine Birds
(Heighten Science Publications Corporation, 2023-07-26) Morrison, Ann; Lukaszewicz, Sonja
Seabirds are species in a collection of avian orders that live on and feed in saltwater and include penguins; albatrosses and petrels; gannets and cormorants; and gulls, terns, and auks. They are at risk from human activities with habitat loss, fisheries bycatch, food shortages, introduced predators and pollution impact. These effects are all exacerbated by human-induced climate change. Many researchers, non-governmental organizations, communities, and governments are working to conserve endangered seabird species by developing and implementing technologies and conservation management systems to assist seabird conservation. More recently moves are afoot to ensure organizations share data and outcomes.
A Preliminary Investigation into the Degradation of Asbestos Fibres in Soils, Rocks and Building Materials Associated with Naturally Occurring Biofilms
(MDPI, 2024-01-19) Berry, TA; Wallis, S; Doyle, E; de Lange, P; Steinhorn, G; Vigliaturo, R; Belluso, E; Blanchon, D
Bioremediation utilizes living organisms such as plants, microbes and their enzymatic products to reduce toxicity in xenobiotic compounds. Microbial-mediated bioremediation is cost effective and sustainable and in situ application is easily implemented. Either naturally occurring metabolic activity can be utilized during bioremediation for the degradation, transformation or accumulation of substances, or microbial augmentation with non-native species can be exploited. Despite the perceived low potential for the biological degradation of some recalcitrant compounds, successful steps towards bioremediation have been made, including with asbestos minerals, which are prevalent in building stock (created prior to the year 2000) in New Zealand. Evidence of the in situ biodegradation of asbestos fibres was investigated in samples taken from a retired asbestos mine, asbestos-contaminated soils and biofilm or lichen-covered asbestos-containing building materials. Microbial diversity within the biofilms to be associated with the asbestos-containing samples was investigated using internal transcribed spacer and 16S DNA amplicon sequencing, supplemented with isolation and culturing on agar plates. A range of fungal and bacterial species were found, including some known to produce siderophores. Changes to fibre structure and morphology were analysed using Transmission Electron Microscopy and Energy-Dispersive X-ray Spectroscopy. Chrysotile fibrils from asbestos-containing material (ACMs), asbestos-containing soils, and asbestos incorporated into lichen material showed signs of amorphisation and dissolution across their length, which could be related to biological activity.
A Review of Extant Literature and Recent Trends in Residential Construction Waste Reduction
(SAGE Publications, 2024-04-10) Albsoul, Hadeel; Doan, Dat Tien; Aigwi, Itohan Esther; GhaffarianHoseini, Ali
The residential construction sector in New Zealand and worldwide is experiencing increased criticism for generating substantial waste that poses environmental concerns. Accordingly, researchers have advocated implementing residential construction waste reduction (RCWR) strategies as a sustainable solution to managing construction waste (CW). This article aims to provide a comprehensive overview of RCWR by analysing 87 articles from the Scopus database using bibliometric and critical review methods. The co-occurrence analysis of keywords revealed five clusters, in which five main themes emerged: (i) waste generation and management performance, (ii) prefabrication and life cycle assessment concepts, (iii) design concepts, (iv) circular economy and (v) decision-making concepts. The findings suggest that sustainable practices such as designing for waste reduction, prefabrication, waste quantification, three-dimensional printing and building information modelling can effectively achieve RCWR. The study also highlights the benefits of RCWR, including reducing environmental impacts, and identifies management, economic, legislative, technology and cultural barriers that affect the implementation of RCWR strategies. These results provide valuable insights to support future policy formulation and research direction for RCWR in New Zealand.
A Review of the Current State and Future Trends in Modern Methods of Construction Research
(Emerald, 2024-02-27) Doan, Dat; Mai, Tuyet Phuoc Anh; Ghaffarian Hoseini, Ali; Ghaffarianhoseini, Amirhosein; Naismith, Nicola
Purpose This study aims to identify the primary research areas of modern methods of construction (MMC) along with its current trends and developments. Design/methodology/approach A combination of bibliometric and qualitative analysis is adopted to examine 1,957 MMC articles in the Scopus database. With the support of CiteSpace 6.1.R6, the clusters, leading authors, journals, institutions and countries in the field of MMC are examined. Findings Offsite construction, inter-modular connections, augmenting output, prefabricated concrete beams and earthquake-resilient prefabricated beam–column steel joints are the top five research areas in MMC. Among them, offsite construction and inter-modular connections are significantly focused, with many research articles. The potential for collaboration, among prominent authors such as Wang, J., Liu, Y. and Wang, Y., explains the recent rapid growth of the MMC field of research. With a total of 225 articles, Engineering Structures is the journal that has published the most articles on MMC. China is the leading country in this field, and the Ministry of Education China is the top institution in MMC. Originality/value The findings of this study bear significant implications for stakeholders in academia and industry alike. In academia, these insights allow researchers to identify research gaps and foster collaboration, steering efforts toward innovative and impactful outcomes. For industries using MMC practices, the clarity provided on MMC techniques facilitates the efficient adoption of best practices, thereby promoting collaboration, innovation and global problem-solving within the construction field.
An Analysis of the Literature on Construction Employee Turnover: Drivers, Consequences, and Future Direction
(Taylor and Francis Group, 2024-04-22) Abdolmaleki, Goldis; Naismith, Nicola; Ghodrati, Nariman; Poshdar, Mani; Babaeian Jelodar, Mostafa
Employee turnover is a critical factor affecting organizational effectiveness. It is particularly important in the construction sector due to its knowledge and labor-intensive characteristics. Therefore, it is necessary to understand why qualified employees would leave their employers so that effective measures can be taken to retain them. Despite the growing body of knowledge on employee turnover, there is a lack of comprehensive review of this topic in the construction literature. This study adopts a systematic literature review approach to synthesize domain knowledge on employee turnover from two perspectives: its investigated causes, and consequences. In total, 77 relevant papers are extracted. A total of 51 drivers of construction employee turnover are identified and categorized into personal, job-related, organizational, and external influencers. Findings also suggest three major outcomes caused by employee turnover, including individual, project, and organization-related consequences. This review contributes to understanding the turnover phenomenon in construction literature and highlights potential areas for future empirical studies to move forward. By understanding the main factors influencing turnover decisions, construction organizations can develop and implement effective means for managing employee turnover. This study further contributes to construction employee turnover research by emphasizing the importance of studying the consequences of the turnover phenomenon.
An Integrated Framework for Production and Environmental Waste Management in Construction
(IGLC, 2024-06-15) Alazmi, Saleh; Abdelmegid, Mohammed; Sarhan, saad; Poshdar, Mani; Gonzalez, Vicente
Lean construction has successfully developed and utilised several tools to minimise production waste generation in construction projects. In addition, sustainability research has contributed to improving the environmental performance of the construction industry by managing the impact of construction waste on the environment. Research on construction sustainability has been utilising some of the capabilities of lean construction tools to address environmental-related issues that are difficult to tackle using conventional approaches. Even though research in the Lean-Sustainability area has progressed over the last two decades, knowledge of Lean-Sustainability applications is still limited amongst industrial practitioners. A potential reason is the lack of an integrated approach combining lean principles and sustainability for construction applications. To address this limitation, this paper proposes a management framework that deals with both production and environmental wastes concurrently. The framework is developed by combining a lean process improvement method with an environmental management system approach. The framework is validated through interviews with experts in lean construction and sustainability to establish its theoretical contribution and practical applicability. Through this integrated waste management framework, this study contributes to the efforts of managing production and environmental wastes to deliver more efficient and environmentally friendly projects in the construction industry.
An Investigation on the Impact of the COVID-19 Pandemic on New Zealand’s Knitwear Manufacturing Sector
(Taylor and Francis Group, 2023-02-01) Nautiyal, Mitali; Joseph, Frances; Hunting, Amabel
Knitwear producers in New Zealand are looking for ways to deal with the uncertainties that have arisen due to the COVID-19 pandemic. This research considers the impact of the pandemic and its effects on the development and long-term survival of the knitwear sector. An anonymous online survey was undertaken among New Zealand’s established knitwear manufacturers, with seven taking up the survey. The respondent companies accounted for around half of the total workforce employed in the country’s knitwear sector. The data were analysed using both quantitative and qualitative methods. A SWOT analysis was conducted to place the sector in a global context, identifying necessary measures for future strategic planning. The findings revealed that the supply chain has been disrupted, some businesses have stalled, and the cost of obtaining raw materials has skyrocketed. Due to the impact of the pandemic on the tourism industry, revenues have fallen. As COVID-19 is an ongoing challenge, knitwear manufacturers need to rearrange their supply chains to increase local suppliers and explore new and innovative ways to engage with domestic customers.
Analyzing the Lean Principles in Integrated Planning and Scheduling Methods
(International Group for Lean Construction, 2023-06-26) Sheikhkhoshkar, Moslem; El-Haouzi, Hind Bril; Aubry, Alexis; Hamzeh, Farook; Poshdar, Mani
The shortcomings and limitations of conventional planning and scheduling methods led to a great deal of emphasis on combining them and developing integrated scheduling methods. Also, lean principles and tools are included in the integrated scheduling methods' structure to develop more effective scheduling strategies. This paper implements a multi-step methodology to identify and analyze the lean principles utilized in integrated scheduling methods. The findings show that integrated scheduling methods, Building Information Modelling (BIM)-Last Planner System (LPS)-Kanban, BIM-LPS, Location-based Management System (LBMS)-LPS-CPM, and BIM-LBMS have included a variety of lean principles into their frameworks. Moreover, improving the reliability of the planning, increasing transparency, identifying and eliminating waste, detecting and solving spatiotemporal conflict, enabling the coordination of the look-ahead plans, and continuous flow of work have received the most attention in the integrated scheduling methods. This paper contributes significantly to the body of knowledge by raising project stakeholders' awareness of the lean principles utilized in integrated scheduling methods in construction projects.
Applications of Building Information Modelling in the Early Design Stage of High-Rise Buildings
(Elsevier BV, 2023-05-11) Omrany, H; Ghaffarianhoseini, A; Chang, R; Ghaffarianhoseini, A; Pour Rahimian, F
High-rise buildings consume more energy and have greater environmental impacts, emphasising the need to adopt best practices during the design stage concerning BIM employment. However, despite strong support from the literature, little is known about the applications of BIM in high-rise buildings at the early design stage. Therefore, this paper aims to provide a holistic understanding of the current applications of BIM in high-rise buildings by analysing 60 studies. The findings identified seven research themes, including studies that used BIM for i) optimising building energy efficiency design; ii) collaborative design and planning; iii) life-cycle assessment; iv) designing net-zero energy buildings; v) integrating BIM with smart technologies for designing high-rise buildings; vi) cost analysis, and vii) structural design of high-rise buildings. Furthermore, this study highlights a number of challenges hindering the widespread application of BIM, alongside providing potential directions for the future development of BIM employment in high-rise buildings.
BIM Knowledge Transfer in Construction Industry: A Partial Least Square Analysis
(Emerald, 2022) Rotimi, EOO; Rotimi, FE; Silva, CWC; Aigwi, IE
Purpose There are several technologies positively impacting the management of construction projects. Building information modelling (BIM) is one such technology, slowly changing project delivery. However, enhancing knowledge transfer (KT) within the construction industry is crucial because of the characteristic slow uptake of innovation. Therefore, this study aims to establish the effectiveness of the KT mechanism for BIM implementation in construction organisations. Design/methodology/approach This study adopted a quantitative research method where a structured questionnaire was distributed to construction professionals. A partial least square structural equation modeling path analysis was used to test the direct and indirect relationships of computer self-efficacy (CS), perceived ease of use (PEOU), KT and BIM usage. Findings This study found that CS could improve KT, which will, in turn, increase the implementation of BIM within construction organisations. However, in terms of KT, individuals’ confidence and ability to use BIM inspires them to share the knowledge of BIM they had received through training. Furthermore, this study found that the ease of interacting, learning and being skilful with BIM may not necessarily ensure the actual transfer of knowledge. Originality/value This study provides valuable insights into KTs (BIM implementation) in the construction industry. It will enhance the use of BIM systems and related knowledge through effective training amongst construction practitioners. Other previous studies have focused on challenges and barriers to BIM implementation, this study goes deeper into establishing the effectiveness of the KT mechanism for BIM implementation in construction organisations.
Biodiverse Residential Development: A Review of New Zealand Policies and Strategies for Urban Biodiversity
(Elsevier BV, 2024-04-01) Varshney, K; MacKinnon, M; Zari, MP; Shanahan, D; Woolley, C; Freeman, C; Heezik, YV
Urban residential development is expanding globally to accommodate increasing housing demand, greatly impacting biodiversity and human wellbeing. Enhanced sustainability of these developments requires an integrated approach to conserving, supporting, and restoring biodiversity through the built environment and understanding the implications of residential development policies, regulations, and guidelines. This paper details a review of current New Zealand policies, strategies, planning documents, and design guidelines that inform urban design and planning at national, regional, and local levels. Three major gaps in biodiversity considerations and opportunities for improvement in residential developments were identified. Firstly, current policies and strategies tend to protect significant indigenous habitats, but the interventions required to improve or retain biodiversity in residential developments are not explicitly considered. Secondly, there is a need for design guidelines with explicit biodiversity outcomes. Thirdly, existing planning documents and guidelines do not account for biodiversity monitoring and management and could be amended to include biodiversity-related outcomes. We conclude that current New Zealand policies and strategies related to residential developments are inadequate and fail to recognise or encourage the enhancement of urban biodiversity in any meaningful way. Holistic and strategic ecosystem-based approaches are required to protect and enhance urban biodiversity and human wellbeing through the built environment to ensure that biodiversity continues to thrive in New Zealand cities and enrich the lives of urban residents.
Centring Localised Indigenous Concepts of Wellbeing in Urban Nature-Based Solutions for Climate Change Adaptation: Case-Studies from Aotearoa New Zealand and the Cook Islands
(Frontiers Media SA, 2024-02-02) Mihaere, Shannon; Holman-Wharehoka, Māia-te-oho; Mataroa, Jovaan; Kiddle, Gabriel Luke; Pedersen Zari, Maibritt; Blaschke, Paul; Bloomfield, Sibyl
Nature-based solutions (NbS) offer significant potential for climate change adaptation and resilience. NbS strengthen biodiversity and ecosystems, and premise approaches that centre human wellbeing. But understandings and models of wellbeing differ and continue to evolve. This paper reviews wellbeing models and thinking from Aotearoa New Zealand, with focus on Te Ao Māori (the Māori world and worldview) as well as other Indigenous models of wellbeing from wider Te Moana-nui-a-Kiwa Oceania. We highlight how holistic understandings of human-ecology-climate connections are fundamental for the wellbeing of Indigenous peoples of Te Moana-nui-a-Kiwa Oceania and that they should underpin NbS approaches in the region. We profile case study experience from Aotearoa New Zealand and the Cook Islands emerging out of the Nature-based Urban design for Wellbeing and Adaptation in Oceania (NUWAO) research project, that aims to develop nature-based urban design solutions, rooted in Indigenous knowledges that support climate change adaptation and wellbeing. We show that there is great potential for nature-based urban adaptation agendas to be more effective if linked closely to Indigenous ecological knowledge and understandings of wellbeing.
Co-designing Collective Housing for a Regenerative Future: Lessons from Indigenous Communities in Aotearoa New Zealand and South America
(School of Art and Design, Auckland University of Technology, 2023-12-21) Besen, Priscila
Since moving to Aotearoa New Zealand, I have been attempting to learn about Mātauranga Māori and understand how we can embed values from local cultures and traditional knowledges into the design of our future built environments. These learnings help me rethink architectural design and pedagogy not only here, but also in my home country, Brazil, and the wider South American context. In the global context of climate and ecological crises, Indigenous knowledge can help us learn to live lives with a closer connection to the natural environment, to be mindful of the use of natural resources and to be more collective-oriented. Indigenous perspectives are important in our transition to a regenerative future, where we aim to go beyond sustainability to create positive impacts for ecology, health and society. In this context, I have been working with a team of researchers from Auckland University of Technology and Pontificia Universidad Católica de Valparaíso, Chile, on a project investigating co-design practices to develop better housing models with Indigenous communities. Indigenous concepts of ‘home’ are multidimensional and often extend beyond the physical and social environments where people live. Although there are diverse cultures across the world, fundamental ideals of ‘home’ are shared amongst many Indigenous communities, such as relationships that connect a person to all that surrounds them, connections to other people, living beings, land, ancestors, stories, languages, and traditions. Most housing options in colonised countries have tended to promote values of individualisation, private property rights and nuclear family units; public housing policies and architectural designs have often been imposed on indigenous communities based on non-indigenous ideals of good housing. However, more recently, these original values and collective forms of living have been re-emerging across the globe, with many successful examples of new collective housing co-designed with Indigenous communities. This presentation will share findings from this research carried out in Aotearoa New Zealand and South America, which investigates contemporary housing solutions co-designed with Indigenous communities. Case studies from different countries are explored, and interviews with architects reveal key lessons learned in participatory practices with residents. The findings show differences and similarities across the Pacific, highlighting key valuable shared principles that can be applied to all forms of housing for a regenerative future, such as multigenerational relationships, connection to the natural environment, shared spaces and resources and initiatives to create a real sense of community. The lessons learned about co-design processes can be valuable for designers working with collective housing in the Global South and other areas across the globe.
Cognitive Biases That Influence Lean Implementation and Practices in a Multicultural Environment
(Emerald, 2023-04-25) Purushothaman, Mahesh Babu; Seadon, Jeff; Moore, Dave
Purpose The purpose of this paper is to highlight the prominent cognitive biases that influence Lean practices in organisations that have a multi-cultural work environment which will aid the organisational managers and academics in enhancing the understanding of the human thought process and mitigate them suitably. Design/methodology/approach A multiple case study was conducted in organisations that were previously committed to Lean practices and had a multi-cultural work environment. This research was conducted on five companies based on 99 in-depth semi-structured interviews and seven process observations that sought to establish the system-wide cognitive biases present in a multi-cultural Lean environment. Findings The novel findings indicate that nine new biases influence Lean implementation and practices in a multi-cultural environment. This study also found strong connectivity between Lean practices and 45 previously identified biases that could affect positively or negatively the lean methodologies and their implementation. Biases were resilient enough that their influence on Lean in multi-cultural workplaces, even with transient populations, did not demonstrate cultural differentiation. Research limitations/implications Like any qualitative research, constructivism and narrative analyses are subjected to understanding based on knowledge gained on the subject, and data may have been interpreted differently. Constructivist co-recreation of process scenarios based result limitations is therefore acknowledged. The interactive participation in exploring the knowledge sought after and interaction that could have a probable influence on the participant need to be acknowledged. However, the research design, multiple methods of data collection, generalisation based on data collection and analysis methods limit the effects of these and findings are reliable to a greater extent. Practical implications The results can provide an enhanced understanding of biases and insights into a new managerial approach to take remedial steps on biases’ influence on Lean practices that can result in improved productivity and well-being from a business process perspective. Understanding and mitigating the prominent biases can aid Lean manufacturing processes and support decision makers and line managers in improving lean methodologies’ effectiveness and productivity. The biases can be negated and used to implement decisions with ease. The influence of biases and the model could be used as a basis to counter implementation barriers. Originality/value To the best of the authors’ knowledge, this is the first study that connects the cognitive perspectives of Lean business processes in a multi-cultural environment to identify the cognitive biases that influence Lean practices in organisations that were previously committed to Lean practices. The novel findings indicate that nine new biases and 45 previously identified biases influence Lean implementation and practices in a multi-cultural environment. The second novelty of this study shows the connection between cognitive biases, Lean implementation and practices in multi-cultural business processes.
Combating Greenwashing of Construction Products in New Zealand and Australia: A Critical Analysis of Environmental Product Declarations
(MDPI AG, 2024-11-06) Moshood, Taofeeq Durojaye; Rotimi, James Olabode Bamidele; Rotimi, Funmilayo Ebun
The construction industry’s increasing environmental impact has led to the widespread adoption of sustainability claims, yet the prevalence of greenwashing—where organizations make misleading environmental claims—threatens genuine sustainable development efforts. Environmental Product Declarations (EPDs) have emerged as a potential solution, particularly in the New Zealand and Australia construction sectors, where recent government climate regulations have accelerated their adoption. However, the effectiveness of EPDs in combating greenwashing and their practical implementation remain understudied. This research addresses this gap through a comprehensive analysis of EPDs in construction, employing a systematic literature review of 82 articles from 2010 to 2024 across major databases. Using ATLAS.ti 9 software, this study makes three key contributions: (1) develops a novel framework for evaluating EPD programs and their effectiveness in preventing greenwashing, (2) establishes a standardized methodology for assessing the completeness and accuracy of life cycle assessment information in EPDs, and (3) provides evidence-based recommendations for improving EPD implementation in the construction industry. The findings reveal critical shortcomings in current EPD practices, including inconsistent assessment methodologies and incomplete life cycle data. This study proposes specific reforms to enhance EPD reliability and transparency, offering practical guidelines for industry stakeholders to verify environmental claims. These contributions advance both the theoretical understanding of environmental certification systems and practical implementation of sustainable construction practices by developing regulatory frameworks.
Computer Graphics and Extended Reality Courses for the Programmophobic
(ACM, 2023-12-06) Marks, Stefan; Gil Parga, Sebastián
This paper describes the challenges and solutions to teaching computer graphics as well as extended reality concepts to students from a variety of backgrounds in the context of the School of Future Environments at the Auckland University of Technology, New Zealand. Examples are provided for the content and assessment strategies for two courses, as well as a summary of student work and feedback collected over the last three years.
Construction Procurement Selection Criteria: A Review and Research Agenda
(MDPI AG, 2022-11-17) Ying, F; Zhao, N; Tookey, J
This paper presents a comprehensive literature review that addresses procurement selection criteria associated with procurement system evaluation in the construction sector. The aim is to consolidate the knowledge of construction procurement selection criteria (PSC) and provide future research directions. A systematic literature review (SLR) of 37 peer-reviewed journal articles from 1998 to 2019 in the construction procurement system selection process is carried out to understand the extant theoretical and practical foundations of the field. Two hundred fifty-six PSC have been identified. Descriptive and material analysis reveals (1) PSC evolved to match the promotion of emerging procurement systems in the construction industry; (2) three emerging themes of PSC have been identified, namely procurement systems, decision aid tools, and PSC identification methods; (3) PSC could be classified into generic criteria and unique criteria; (4) geographic location may not have a significant impact on the choice of procurement systems. This work identifies and discusses potential research interests in improving PSC identification. The research path, current trends, and future research directions in construction procurement selection are revealed. The paper provides the foundation and impetus for further investigation into procurement system selection practices.
A Critical Investigation on the Reliability, Availability, and Maintainability of EPB Machines: A Case Study
(MDPI AG, 2022-11-06) Kalatehjari, R; koohsari, A; Moosazadeh, S; Hajihassani, M; Van, B
Tunnelling is a vital geotechnical engineering feature of underground transportation systems that is potentially hazardous if not properly investigated, studied, planned, and executed. A reliability, availability, and maintainability (RAM) analysis is one of the main practical techniques in machinery-based projects to recognize the failure and repair rates of machines during or after their operations. RAM analysis of mechanized tunneling can help to manage the project safety and cost, and improve the availability and performance of the machine. There are several methods to obtain and predict the RAM of a system, including the Markov chain simulation and other statistical methods; however, the result of the analysis can be affected by the selected method. This paper presents the results of a critical investigation on the RAM of the Earth pressure balance machines (EPBMs) used in developing an urban metro project in Isfahan, Iran. The five kilometer length of the first line of the Isfahan metro project was excavated using EPBMs over four years. After overhauling the EPBMs and making some minor changes, excavation of the second line started, and to date, about 1.2 km has been excavated by the refurbished machines. In the present study, a RAM analysis has been applied to electrical, mechanical, and cutter head subsystems of the EPBMs in Lines 1 and 2 of the Isfahan metro project over an 18- and 7-month period of machine operation, respectively. The results show that the estimated availability, A(t), determined by the Markov method, is closer to reality but cannot be propagated to reliability R(t) and maintainability M(t) analysis. It was also revealed that by predicting the required maintenance and proper planning, the overall availability of the EPBM was improved from 45% in Line 1 to 61% in Line 2. The outcomes of this study can be used in the future planning of urban tunneling projects to estimate machine, staff, and logistic performance with the least possible error, and appropriately arrange the factors involved in the system.
Critical State Characterization of New Zealand East Coast Sand for Numerical Modeling
(Springer Science and Business Media LLC, 2023-08-30) Bolarinwa, Ademola; Kalatehjari, Roohollah; Rashid, Ahmad Safuan A
AbstractThis paper outlines the findings of a laboratory-based and numerical study to investigate the undrained flow failure behavior of East Coast Sand (ECS). ECS is a commonly encountered coastal deposit from the upper North Island of New Zealand. The study focused on establishing the undrained strength characteristics of ECS under static, triaxial compressive loading conditions, and at confining pressures in the range of typical engineering interest and for a range of soil densities considered in loosely deposited sands. The research objectives of establishing the basic soil properties and the intrinsic advanced geomechanical properties specific to ECS from Auckland were achieved through laboratory experiments and matching numerical simulations with an advanced critical-state compatible soil constitutive model (Norsand). The current work examined five different aspects of the ECS undrained behavior under static loads. It was shown that loosely deposited ECS within mean effective stresses ranging between 50 and 200 kPa was highly susceptible to expensive flow failures of structures built on or with them. The obtained approximate peak undrained shear strengths before failure and critical states were 29 kPa, 84 kPa, 130 kPa, and 200 kPa for test confining stresses of 50 kPa, 100 kPa, 200 kPa, and 300 kPa, respectively. Similarly, the corresponding excess pore water pressures were 48 kPa, 98 kPa, 200 kPa, and 240 kPa, respectively. The above results proved that the soil’s effective and confining stress are key determinants of the soil’s undrained shear strength characteristics which was consistent with the existing literature.

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