From planning to performance: MRP-driven material optimization for the bored pile construction of the MUI and Safa-Marwa towers in Indonesia

PT. Prima Jaringan is an Indonesian company operating in the property sector. One of its ongoing residential facility development projects is the construction of the MUI Tower and Safa-Marwa Tower in Jakarta. A key issue encountered during the project was the insufficient availability of construction materials when needed, primarily due to inadequate material requirement planning. This problem was particularly evident during the construction of the bored pile foundation for the MUI Tower, where there was a shortfall of 18 m³ of ready-mix concrete (fc’30) in the 20th week. This shortage led to delays in the project schedule. The aim of this study is to analyze material inventory planning for the bored pile construction of the Safa Tower. The inventory planning method employed is Material Requirement Planning (MRP). The required data include general project information, the master schedule, material data, lead times, and the bill of materials. The study applies four lot-sizing techniques: Lot for Lot (LFL), Economic Order Quantity (EOQ), Period Order Quantity (POQ), and Part Period Balancing (PPB). Among these, the most optimal lot-sizing technique is identified based on the minimization of order quantity and inventory costs. The results of the analysis indicate that the Part Period Balancing (PPB) technique yields the lowest cost for multiplex phenolic film and ready-mix concrete fc’30. Meanwhile, the Period Order Quantity (POQ) technique results in the lowest cost for D13, D16, and D19 reinforcement bars.