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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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Author: search.filters.author.Aiyetan, Olatunji Ayodeji

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    Using system dynamics principles for conceptual modelling to resolve causes of rework in construction projects
    (University of Johannesburg Department of Construction and Quantity Surveying, 2015) Aiyetan, Olatunji Ayodeji; Das, Dillip
    Rework in construction projects has brought in two major challenges: cost overruns and delay. In this regards a study was conducted by considering various construction projects in the South West part of Nigeria to understand the causes of rework and the interventions to mitigate it. Survey research methodologies followed by the conceptual system dynamics (SD) modelling were used in the analysis. This study identified the sources of rework in construction projects from the design related, the client related and the contractor related issues and attempted to derive policy/strategic interventions to limit or eliminate rework on construction projects and its delivery by using conceptual SD models based on the influence of the variables on rework. The findings include that inappropriate scheduling for time pressure or delay at the planning stage, lack of adherence to specifications, and non-availability of skilled human resource are the major causes of rework. However, rework in construction projects would be reduced or eliminated through policy interventions, such as, achieving client satisfaction with scheduling for time pressure or delay at the planning stage, adherence to specifications ensuring quality of work resulting in client satisfaction, and the availability of skilled manpower ensuring quality management.
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    Resolving contractor commitment challenges in project delivery by using conceptual system dynamics models
    (University of Johannesburg, 2016) Aiyetan, Olatunji Ayodeji; Das, Dillip
    Contractors play a vital role in construction projects. However, their lack of commitment is argued to be one of the major barriers against successful project delivery. This investigation was aimed at to explore how contractor commitment challenges can be resolved to improve their performance in the project delivery. A survey research method was used to collect data, and Likert scale was applied to evaluate the relative importance of the contractor commitment challenges. Followed by conceptual System Dynamics (SD) modelling principle was used to develop causal feedback relationships among the variables influencing contractor commitment and to develop mechanisms to resolve the challenges. Findings suggest that lack of experience, skill, inadequate supervision, and lack of control over the subcontractors lead to contractor’s inefficiency. Poor planning and scheduling, poor professional management, poor execution of projects, ineffective/outdated equipment, and inefficiency of labour force result in poor quality of work and delay. In addition, design and documentation challenges disrupt the contractors’ schedule. The interlinkage among these variables hinders contractor commitment. However, policy/strategic interventions based on the causal feedback relationships among contractor efficiency, and (1) capacity building; (2) professional management; (3) construction methods; and (4) involvement of the contractor and client in the design process would enable the contractors to overcome their challenges to meet their commitment and improve efficiency in project delivery.
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    A system model for project delivery time and implementation
    (Association of Schools of constructions of Southern Africa, 2015-12) Aiyetan, Olatunji Ayodeji; Smallwood, J.J.; Shakantu, W.
    Purpose: Professionals undertake tasks as part of inter alia, the design process, which require a range of actions, which are substantially influenced by the environment. Given that the interplay of all of these forces has an impact on the outcome of the process, the study reported on investigated the relation-ships between actions initiated by professionals in the delivery of facilities. Methodology: The mix method of research approaches (qualitative and quantitative) were adopted in the study. The ï¬ rst part deals with the quantitative approach, which led to the second part the qualitative approach and that system thinking. The system thinking approach was employed to identify causes and effects of actions / decisions undertaken during the delivery of facilities. Respondents were selectedrandomly. The questionnaire the instrument used for data gathering was administered to respondents through post and e-mail. The data for the study was obtained from eighty-nine respondents within the metropolitan areas of the following provinces in South Africa, namely: Gauteng, Kwazulu-Natal, Eastern Cape, Western Cape, and Free State. Architects, clients, contractors, engineers, and quantity surveyors constitute the respondents. Findings: Findings from the study include: lack of commitment to timeous completion of projects on the part of contractors, clients, and designers leads to project delay; poor performance stems from late payment of fees, and lack of adequate prequalification of professionals; late provision and issuance of instructions and approval of works leads to project delay, and contractors’ inadequate skills and health and safety (H&S) plans lead to poor performance and late project delivery. Practial implication: The causes and consequences of delay have been identified. The breaking of the circle of factors that lead to project delay based on the actions that will enhance delivery of projects should be given greater attention. Value: The practice of the recommendations based on the findings from the study will drastically reduce delay in the delivery of building construction projects.