Analisis Time-Cost Trade Off Pada Percepatan Struktur dan Arsitektur, dengan Metode Cast In Situ dan Precast terhadap Efisiensi Waktu dan Biaya (Studi Kasus RSUD Dr.Loekmonohadi Kudus) 27 35

Abstract

High-rise building projects frequently experience schedule delays when field progress falls behind the baseline S-curve, so acceleration is required to restore the planned completion date. Overtime on cast in situ work, the most common approach, is constrained by concrete curing time and by declining productivity due to worker fatigue; precast concrete is therefore considered as an alternative. This study compares both acceleration schemes for the structural and wall works of the Stroke and Oncology Building, RSUD dr. Loekmonohadi Kudus, using the Time Cost Trade Off (TCTO) method. Secondary data (bill of quantities and time schedule) were analysed with the Critical Path Method (CPM) and cost slope, while primary data from questionnaires completed by 34 respondents were analysed using the Relative Importance Index (RII). Both schemes shorten the project duration from 136 to 109 days (27 days or 19.85%); at activity level, precast reduces the cumulative duration of structural and wall works from 350 to 154 days (56%). At 109 days, the overtime scheme yields a total cost of Rp19,130,607,056.57 (+6.54%), whereas the precast scheme yields Rp21,107,070,024.00 (+17.55%), with cost slopes of Rp50.69 million/day and Rp123.90 million/day, respectively. Respondents rated the weather vulnerability of cast in situ work (RII = 0.83) and the controlled quality of precast elements (RII = 0.82) as the most important factors. Overtime is the least-cost option to reach the 109-day target, while precast is recommended when schedule certainty, work safety, and minimal disturbance to hospital operations are prioritized, provided that heavy-equipment mobilization and factory supply are properly planned.