Study on the Application of Just-In-Time Philosophy to Construction: A Case Study of Reinforcement Bar Production and Delivery System
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Date
2023-05
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Addis Ababa University
Abstract
In cities like Addis Ababa, storage and working space are usually inadequate for construction projects. Construction materials like rebar require a lot of space for storage and production. For the temporary storage and production of rebar, some firms had to pay extra to rent space. Also, some use the roadside for storage and production areas. Furthermore, most activities performed during the construction process do not add value to the project but incur unnecessary costs and time that affect the project's performance. Therefore, this study intends to analyze the rebar production practice and explore whether applying the just-in-time concept to the rebar production and delivery system would be advantageous from the perspective of value. To achieve the study objective, case studies were carried out on two contractors. The contractors were selected based on their approaches to rebar production. The first one uses the on-site rebar production method, while the other contractor uses off-site rebar production with JIT delivery. The data collected from case studies was analyzed using descriptive analysis and by developing a discrete event simulation model. Finally, the study's findings revealed that there is a considerable amount of non-value-added and necessary but non-value-adding activities on site during the production of rebars. According to the simulation analysis result, off-site rebar production with JIT delivery is shown to decrease rebar production time, increase productivity, and decrease idleness of labor and machines. Additionally, the study revealed the motivating and challenging factors for JIT implementation. In general, on the basis of value, applying JIT to rebar production and delivery is efficient. Thus, it is important for construction companies to start considering the benefits of this production and delivery system.