Browsing by Author "Biruk, Leggesse"

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    Modeling Structural Works Construction Duration: A Case Study of Selected Apartment Projects in Addis Ababa
    (Addis Ababa University, 2020-10) Biruk, Leggesse; Abraham, Assefa (PhD)
    There is a recognized need for accurate estimation of construction duration of buildings. Uncertainties in duration estimation hindered a problem to the construction sector. With this regard, approximate estimation of the various phases of building construction indicated to minimize the uncertainty in duration estimation. The structural framework construction phase covers nearly half of the building project duration. Further, also this phase almost always present in the critical path of project schedule. With this regard, accurate and early prediction of structural frameworks duration can help mobilize and manage resources effectively. Thus, this study provides parametric models that ease this need. Case study samples of 41 apartment residential buildings constructed and completed between a period from 2010 and 2019 were collected using structured questionnaire. 33 of the sample used to develop duration prediction models using linear regression analysis, while the remaining 8 samples used to validate developed models. In order to develop mathematical models first, the interrelationship that exist between structural works duration influencing factors; project scope factors and quantity of work items investigated. Project scope factors; total gross floor area, and typical floor area showed a statistically significant moderate strength positive linear relation. Similar linear relations were also observed with quantity of work items; quantity of excavation, formwork, reinforcing bar, and quantity of concrete. Simple and multiple linear regression analysis carried out resulted in models with low coefficient of determination. But, best-fit models were developed, by splitting the model building data set into small-size and large-size projects based on total gross floor area and removing outliers. More than 85 percent of significant variance in structural frame work duration by selected project scope and quantity of work item predictor variables was accounted by best-fit models. The present study put efforts towards enhancing our understanding of relationships existing between selected predictor variables and structural works construction duration.