Analisis Waste Material Menggunakan Metode Lean Construction (Studi Kasus: Proyek Pembangunan Panti Sosial Rehabilitasi Medan – Kota Medan)

Abstract

The presence of waste in projects needs to be avoided to prevent losses. In lean construction, processes that potentially lead to waste material can be identified. Many issues are found in construction projects, such as drawing changes, specification alterations, inadequate storage, and technical issues on-site. This study aims to evaluate the types of waste materials, identify processes that generate waste using lean construction methods, and determine the highest and lowest waste levels in the project. Data required for this research include S-curves, Bill of Quantity, and As-Built Drawings. Research methods used include identifying high-cost materials that potentially cause waste, Pareto analysis, calculating installed material volumes, conducting waste level analysis, and identifying processes that generate waste with lean construction. Based on the analysis conducted, the main causes of waste materials are defects, overproduction, waiting, and inventory issues. Defects in materials result from building specification changes; overproduction occurs due to lack of optimization; waiting happens when orders are not scheduled properly; and inventory issues stem from inadequate material storage. From the identification of high-cost materials that potentially cause waste and Pareto analysis, four materials were identified as causing significant waste: D16mm steel bars, Ø8mm steel bars, Portland cement, and D13mm steel bars. From the waste level analysis, the percentage of waste, from largest to smallest, is as follows: D13mm steel bars = 4.035%, Ø8mm steel bars = 1.060%, D16mm steel bars = 0.829%, and Portland cement = 0.783%.