Browsing by Author "Poshdar, Mani"

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    Causes of Defects Associated with Tolerances in Construction: A Case Study
    (American Society of Civil Engineers, 2021-04-23) Talebi, Saeed; Koskela, Lauri; Tzortzopoulos, Patricia; Kagioglou, Mike; Rausch, Chris; Elghaish, Faris; Poshdar, Mani
    Defects associated with dimensional and geometric variations (tolerance issues) are among the most costly and recurring defects in construction projects, yet the identification and mitigation of the causes of tolerance issues appear to be lacking in the construction industry. To enable the development of widely acceptable solutions for the perennial challenge of tolerance management, a more in-depth understanding of the causes of tolerance issues should be established. The aim of the research presented in this paper is to identify the potential causes of tolerance issues in construction based on a literature review and empirical studies. This research uses a case study approach. The empirical data are collected through direct observations, group interviews, semistructured interviews, and document reviews. Having triangulated the findings, a list of 18 potential causes was derived for the 11 observed tolerance issues in two case study projects. The contribution of this paper to knowledge in engineering management is fourfold: (1) the limitations of prior studies on causes of tolerance issues are revealed, (2) the empirical studies led to not only verifying and refining the causes collected from the literature by considering them in the context of the identified tolerance issues, but also finding new causes in the context of tolerance management when compared to literature, (3) the identified causes provide insight into reasons behind the recurrence of tolerance issues across the industry, and (4) it investigates the causes of tolerance issues while balancing managerial and engineering views. The findings of this study provide a pivotal basis for construction practitioners to develop effective solutions for tolerance management whereby tolerance risks can be identified and mitigated in a prescient manner, which can result in a significant amount of savings.
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    Labor waste in housing construction projects: an empirical study
    (Emerald, 2021-10-29) Nassri, Soraya; Talebi, Saeed; Elghaish, Faris; Koohestani, Kayvan; McIlwaine, Stephen; Hosseini, M. Reza; Poshdar, Mani; Kagioglou, Mike
    Purpose High-level labor waste is a major challenge in construction projects. This paper aims to identify, quantify and categorize labor waste in the context of Iranian housing construction projects. Design/methodology/approach This research uses a case study approach, with empirical data collected through direct observations and semi-structured interviews. Findings Having triangulated the findings from the literature review and empirical studies, a list of eight types of waste was derived for the thirteen observed laborers in ten case study projects. The empirical studies allowed the labor waste identified from the literature to be verified and refined by considering it in the context of the observed activities, and led to two new types of waste being identified which were not considered in the literature. Findings indicate that nearly 62% of laborers' time is spent on non-value-adding activities. It appeared that “unnecessary movement,” “waiting” and “indirect work” make up the highest labor waste. Research limitations/implications This research focuses only on onsite resource flows in a housing construction site. It does not include offsite flows such as material delivery to site. Originality/value The findings have provided substantial evidence on type and amount of labor waste and provide a solid basis to stimulate construction actors to participate in reducing labor waste and improving productivity.