Modelling uncertainty of cost and time in infrastructure projects

The construction of infrastructure projects is characterised by cost overruns and time delays. Scholars view that the estimation approach and inappropriate tools and techniques used to forecast possible uncertainty in the construction processes are a primary cause of cost overruns and time delays on construction projects. Uncertainties encountered in the construction process are underestimated and these impact on the final cost and time of construction projects through a combination of individual construction activities. The study, therefore, examines the initial and final cost of construction activities, towards developing a hybrid tool that captures and models’ different sources of uncertainty in infrastructure projects and their effect on cost and time underestimation. The study adopted a sequential exploratory mixed method research approach that went beyond the basic mixed method approaches, employing a combination of sequential and concurrent aspects of mixed methods. Data was gathered through a series of expert panel estimation sessions, technical brainstorming of experienced professionals (with 30 years’ experience and more) in the construction of infrastructure projects, and a structured self-administered questionnaire survey distributed to project managers of South African highway projects. The developed hybrid tool models the main structures from the activity level to the entire highway project. Consequently, three identified uncertainties in the construction process of infrastructures, namely variability in the construction process, correlations between the costs, times and cost-time of construction activities and disruptive events, are modelled jointly at the construction activity level. Data obtained from both qualitative and quantitative approaches were analysed using various techniques. The probability distribution function of cost and time were modelled using the lognormal and triangular probability distributions; while Monte Carlo Simulation (MCS), Copula analysis technique, the Markov processes, and Adaptive Neuro-Fuzzy Inference System (ANFIS) analytical technique were used in modelling the variability of the cost and time activity, correlation between costs, time and cost-time activities, and to model the occurrence of disruptive events, so that the impact size of disruptive events on the cost and time of activities respectively, can be intelligently assessed. The developed uncertainty model was validated against the final cost and time of a project case study, as well as against historical data of construction cost overruns and time delays in infrastructure projects. The study found that the different uncertainties had a distinct influence on construction cost and time of different project structures. Furthermore, the comparison of the deterministic estimates with the uncertainty estimates shows that the accumulated impact of the three uncertainty sources significantly increases the construction cost and time of infrastructure projects. Based on these findings, the research concludes that the disruptive event is the main cause of cost overruns and time delays in infrastructure projects. In the scale of activity, the correlation between the costs of different activities in the same structure causes the largest increase in the cost of activity, while the correlation between the times of repeated activity in the same structure causes the largest increase in time of the activity. Furthermore, the study concludes that the improvement in the accuracy of cost and time estimation of infrastructure projects depends on a combination of probability analysis and intelligent machine learning. The contributions of the study to construction management knowledge include a clear definition of uncertainty and the sources of uncertainties in the construction of infrastructure projects; an in-depth understanding of the construction process of linear infrastructure projects; and an improvement in the quality of data used (combination of experts’ estimation and historical data) for research in the area of project performance. The developed uncertainty model based on three sources of uncertainty at the activity level provides infrastructure project planners with a hybrid dynamic tool to accurately model and predict the construction cost and time of infrastructure projects at any stage of the project. Also, the uncertainty model has three other purposes: it is the preparatory point for allocation of budget, it facilitates the update of the impact of uncertainties and evaluates the effectiveness of countermeasures to mitigate against the threat of uncertainties

Key Performance Criteria Influencing the Selection of Construction Methods Used for the Fabrication of Building Components in the Middle East

There is a lack of an efficient systematic approach to the selection of appropriate construction methods for building projects. Not only various innovative methods are now available, but also established methods may often be adapted inappropriately, without recourse to the necessary scientific foundation of their efficiency. The result is that there is a low level of performance on building projects. This study examines how key performance criteria were used in the selection of construction methods on projects. The study employed an extant review of the literature, cross-section survey of construction managers of building projects and experts interview in the Middle East to identify and evaluate the influencing of the key performance criteria on selecting construction methods for building projects. It emerged from the Pearson Correlation Coefficient and Analytical Hierarchy Process analysis that key performance criteria consisting of time, quality, and cost have strong positive significant roles in the selection of construction methods used on building projects and that these selection criteria differed depending on the building components. The study concludes that the likelihood of a construction method being selected for use on projects in the Middle East depends on its ability to shorten the duration, improving the quality and reduce the cost of projects

Improving sustainability of affordable housing using innovative technologies: Case study of SIAH-Livable

Rapid urbanization presents a major challenge in achieving affordable and sustainable housing. In the face of the problem, rapid urbanisation represents, there is room for innovation. Advancements in sustainable design methods, new materials, and innovative building technologies offer potential solutions for developing sustainable, innovative, and affordable housing (SIAH). This study investigates various sustainable design techniques, materials, and technologies suitable for designing SIAH in the South African climate in concordance with local building codes and regulations. The study compares the building performance of SIAH-Livable, as assessed by energy embodied, energy demand, and water usage, with that of conventional low-cost housing using the EDGE Buildings App. The results validate that SIAH-Livable building performance is significantly less water and energy, reducing consumption by 55.17% and 21.06%, respectively. Additionally, SIAH-Livable exhibits a noTable 66.9% reduction in embodied energy levels while remaining within the construction cost range defined by the South African government for low-cost housing. Furthermore, the analysis confirms that appropriate design techniques, new materials, and technologies not only enhance the sustainability of the house but also improve its affordability by reducing lifecycle costs. The study concludes that sustainable design techniques, including passive design, the use of recycled and local materials, and socio-technical innovations, are effective means of enhancing the sustainability and affordability of housing, contributing to the development of SIAH. Importantly, this research establishes the association between sustainability and affordability in South African housing design, offering insights that can be adapted and applied to other African countries

ESTABLISHING THE KEY ELEMENTS OF INCORPORATION AND OUTCOMES OF 4TH INDUSTRIAL REVOLUTION IN BUILT ENVIRONMENT EDUCATION: A MIXED BIBLIOGRAPHIC AND BIBLIOMETRIC ANALYSIS

The rapid, exponential fusion of technologies which profoundly disrupts all industries and processes is commonly described as the Fourth Industrial Revolution (4th IR). The Built Environment (BE) sector has long been overdue for radical transformation that is symphonious with global trends. Consequently, how to incorporate 4th IR in BE education remains challenging. This research aims to establish what educational methods, context, tools, and technological pedagogy are required and should be adopted, as well as what the effects and outcomes can be expected from the incorporation of the 4th IR concepts in BE education. The rationale for this research stems from the aspiration to meet the United Nation Sustainable Development Goals, which advocate that young people need to be "future-ready" and this includes digital fluency and ICT literacy. The study utilised a verifiable and reproducible systematic literature review of digital education; with analysis and scrutiny of 582 academic articles for the co-occurrence of keywords, using a mixed bibliographic and bibliometric method. Through clustering analysis based on the bibliometric method, the key elements, outcomes, and their interconnections of incorporating 4th IR in BE education were outlined. The paper revealed that, in adopting 4th IR, Higher education, Design, Innovation and Privacy appear to be the predominant context. Distance education, Collaborative learning and Digital learning are the foremost education methods. Digital technologies, Virtual reality and cloud computing are the most significant education tools and technology elements. Sustainable education, Ethical learning and Student engagement are the resultant primary outcomes of incorporating 4th IR in built environment education. In addition, the results of the interconnections of indicators analysis revealed Higher education, Distance education and Sustainable education are significantly intertwined with Digital technologies. Based on the taxonomy of key elements and outcomes and the analysis of their interconnections, a conceptual framework for adopting 4th IR in built environment education was develope

Causality between challenges, availability, and extent of use of local building materials

The promotion of sustainable practice in construction has resulted in a renewed focus on local building materials (LBMs). However, existing studies have not provided an extensive understanding of the challenges in the use and awareness of the availability of LBMs. In this study, we examine the challenges in the use and awareness of the availability and environmental performance of LBMs in South Africa. Based on a review of related literature, a questionnaire survey was undertaken to collect data from stakeholders in the construction industry. Structural equation modelling was conducted to validate the causality between the constructs. We found that the negative impacts of the challenges in the use of LBMs significantly reduce if stakeholders are aware of the environmental performance of LBMs in South Africa. The extent of the use of LBMs will increase with an awareness of their environmental performance and availability. Acquisition of the technical knowledge associated with LBM-based construction processes and recognition of the use of LBMs for building projects in building requirements and regulations are recommended. Significance:The study provides an understanding of the challenges in using LBMs linked to construction stakeholder awareness of their availability and environmental performance. This understanding will promote the use of LBMs in the construction industry and provide a valuable reference for stakeholders in decision-making and policymaking on their use

Modeling the neighborhood wellbeing of townships in South Africa

Townships in South Africa are characterized by underdeveloped urban neighborhoods on the periphery of cities, where their inhabitants suffer from a poor quality of life. Given the relative lack of empirical research on the wellbeing of people living in townships in South Africa, this study attempts to fill the gap by understanding and modeling the relationships between household socioeconomic characteristics, housing and neighborhood conditions, and individual and community wellbeing to develop and empirically validate a neighborhood wellbeing framework. The hypothesized associations from the wellbeing framework were tested using 389 household interviews of the three largest townships in South Africa. The findings identify the challenges associated with adequate housing and lack of infrastructure in townships and how these affect the wellbeing of individuals and communities. The conclusion demonstrates how the neighborhood wellbeing framework, as an interdisciplinary approach, can improve the quality of life of inhabitants and communities in urban neighborhoods in general

Revolutionizing affordable housing in Africa: A comprehensive technical and sustainability study of 3D-printing technology

The global challenge of providing affordable and sustainable housing, particularly in Africa's intensified housing crisis, has spurred interest in transformative solutions such as 3D-printing technology. This research addresses a significant gap in understanding the technical and sustainability characteristics of 3D-printed housing, by comprehensively assessing a full-size 3D-printed house. Beyond examining building performance, a thorough life cycle assessment quantifies the whole life cycle carbon and cost, comparing the 3D-printed house with its conventional counterpart. The findings underscore the superior performance of 3D-printed housing in both technical and sustainability aspects. A 48 % reduction in the carbon footprint emphasizes the environmental sustainability of 3D-printed house. Despite a 70 % reduction in construction duration, the initial costs of technology and imported proprietary materials contribute to a higher life cycle cost for the 3D-printed house (381 %) in Africa.These results affirm the potential of 3D-printing as a sustainable and efficient mechanism for revolutionizing the African housing sector by improving performance and expediting delivery. The study provides valuable insights for housing stakeholders, advocating for the judicious use of 3D-printing and local bio-mediated geo-materials to address African housing crises, enhance residents' quality of life, and, consequently, sustain African cities and society

Causality between challenges, availability, and extent of use of local building materials

The promotion of sustainable practice in construction has resulted in a renewed focus on local building materials (LBMs). However, existing studies have not provided an extensive understanding of the challenges in the use and awareness of the availability of LBMs. In this study, we examine the challenges in the use and awareness of the availability and environmental performance of LBMs in South Africa. Based on a review of related literature, a questionnaire survey was undertaken to collect data from stakeholders in the construction industry. Structural equation modelling was conducted to validate the causality between the constructs. We found that the negative impacts of the challenges in the use of LBMs significantly reduce if stakeholders are aware of the environmental performance of LBMs in South Africa. The extent of the use of LBMs will increase with an awareness of their environmental performance and availability. Acquisition of the technical knowledge associated with LBM-based construction processes and recognition of the use of LBMs for building projects in building requirements and regulations are recommended

Interrelationships between sustainability and wellbeing: Three cases from the Global South

This paper seeks to advance the understanding and analysis of the role and impact of housing and neighbourhood characteristics on the wellbeing of communities in the informal settlements in the global south. It provides a holistic view on the relationship between household features, housing design and neighbourhood conditions to assess further their effects on wellbeing constructs in Nepal, South Africa, and Jordan. The COVID-19 pandemic has added to the prevailing challenges for population wellbeing in all cases. The study assessed the relationships between housing design, neighbourhood form, social inclusion, and mental and physical wellbeing through a detailed questionnaire. A comparative analysis allowed identifying the innovative changes and strategies in conjunction with local stakeholders to improve individual and public wellbeing. The study proves the significant relationships between the three dimensions of housing: house conditions and design, household characteristics and neighbourhood conditions, and individual and community wellbeing in informal settlements. The findings discuss multilevel (housing and neighbourhood) solutions and unique social groupings that support livelihood strategies and how these strategies impact the social, economic and environmental sustainability in informal settlements. The resultant importance of specific constructs and sub-constructs offers a toolkit for evaluating informal settlements and potential improvements. This work is also a demonstration of how an interdisciplinary methodology can help mediate societal challenges, particularly when it comes to the wellbeing of inhabitants in informal settlements