Time and cost trade-offs between overtime and workforce expansion for remaining structural work in a building project in Bali
Keywords:
construction scheduling, least-cost analysis, overtime, analysis, project crashing, time–cost tradeoff, workforce expansionAbstract
Schedule acceleration requires comparing additional resource costs with time-dependent overhead savings. This quantitative case study evaluates overtime and workforce expansion for remaining structural work in the XYZ Tabanan building project, Bali, Indonesia. A Microsoft Project precedence network and Microsoft Excel cost calculations compare eight acceleration scenarios with a baseline of 200 working days and IDR 74.414 billion. The Monday–Saturday calendar places the unaccelerated structural completion milestone on 20 October 2026, starting on 2 March 2026 without national-holiday exclusions. Costs comprise IDR 70.000 billion in direct costs, IDR 2.414 billion in allocated fixed indirect costs, and overhead of IDR 10 million per active working day; contractor profit and value-added tax are excluded. In the reported outputs, four hours of overtime yields 114.62 working days and IDR 74.351 billion, while workforce scenario W4 yields 72.98 working days and IDR 74.076 billion. Time reductions are 42.690% and 63.510%, and cost reductions are 0.085% and 0.455%, respectively. Workforce expansion has the lowest reported cost, reflecting overhead savings that exceed its additional direct cost. However, reproducing the accelerated durations requires the activity-level network, calendar settings, and trade-specific resource assignments. The scenario ranking therefore remains conditional on schedule and cost validation.
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