Lean Construction Approach for Handling Waste in Government Building Construction Work

Government building construction projects represent a complex series of activities requiring massive resource integration with strict constraints on cost, quality, and time. The high complexity of work involving cross-disciplinary coordination potentially generates various forms of waste, defined as activities that consume resources without adding value (non-value-adding activities). This study aims to identify the dominant waste factors, analyze their root causes, and formulate mitigation strategies based on the lean construction approach. The essential concept of lean construction relies on detecting and eliminating seven classifications of waste, which encompass overproduction, waiting, transportation, inappropriate processing, excess inventory, unnecessary motion, and defects. Through the systematic reduction of non-value-adding activities, project execution can achieve significantly higher efficiency, accelerated timelines, and greater cost-effectiveness. Data collection was conducted through observations, interviews, and the distribution of questionnaires to project practitioners. Quantitative data analysis was performed using validity and reliability tests, followed by the Borda method for ranking the dominant factors, and Root Cause Analysis (RCA) integrated with the 5 Whys technique to ascertain the root causes. The research findings confirm three primary wastes: (1) Waiting due to unfavorable weather conditions (score 174; weight 0.203), (2) Overproduction in the form of premature material fabrication (score 88; weight 0.117), and (3) Inappropriate Processing manifested as a high frequency of rework (score 114; weight 0.166). The 5 Whys synthesis reveals that these inefficiencies are rooted in the field management's heavy reliance on a highly rigid, conventional scheduling system (Push System). As a proposed improvement, lean construction mitigation strategies were formulated, encompassing the application of the Last Planner System (LPS) and Daily Huddles to adaptively manage weather constraints; the implementation of a Pull System and Work-in-Progress (WIP) limits to regulate the rate of Overproduction; and the application of Built-in Quality principles utilizing Poka-Yoke instruments to prevent repetitive rework.