Comparative Study on The Impact of Materials Wastage on Project Cost Between Prefabricated and On-Site Building Construction Methods: The Case of Ethiopian Construction Works Corporation
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Date
2024-04
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Addis Ababa University
Abstract
Construction material waste is produced due to construction work progress, type of work being done and site procedure on traditional methods of construction projects. As a result, using prefabrication is one of the options for decreasing the waste produced by using prefabricated elements. Prefabrication is the conversion of construction activities from on-site construction methods that produce a lot of waste to industrial procedures that produce little waste.
This study aims to analyze the effects of construction material waste on project costs in Ethiopian Construction Works Corporation between prefabricated and on-site building construction methods. A literature review was carried out to identify sources of construction material waste, prefabricated and on-site construction methods and their material wastage extent, construction material wastage and project cost and waste minimization technics being used in the construction industry. A questionnaire survey, on-site observation, and case studies based on document analysis were carried out in this research. The data obtained from the questioner were analyzed using Microsoft excel. The study focused on the five main materials which are concrete, mortar, reinforcement bar, hollow concrete block and formwork for the greatest influence on the project cost. Based on the respondent answer from contractor and consultant ranked the variable and by document analysis estimate the amount of material waste analytically. From 13 Ethiopian Construction Works Corporation prefabricated and on-site construction project sites, the study show that design change, lack of onsite material control, rework and ordering errors were the main reasons of construction materials wastage.
Finally, according to the results of this study, sand and hollow concrete blocks are largest source of waste in prefabricated and on-site project sites but formwork wastage is only showing on on-site construction and the cost of waste generated at these two sites are 6.23% and 13.84% in prefabricated and on-site construction, respectively. The result of this study recommends that, uses of construction element, proper detail during designing, attention to material control and reduce rework and material ordering errors are the main reasonable technics in Ethiopian Construction Works Corporation construction sites to increase profits and reduce waste.
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On-site construction method, cost, prefabrication, profit, impact.