VALIDASI BATAS ATAS BATAS BAWAH ESTIMASI DURASI GEDUNG KONSTRUKSI BERTINGKAT BERBASIS EARNED SCHEDULE
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Abstract
Determination of estimated project completion is an activity that influenced the planning project since it can decide the success or failure of the project. However, duration is often not in accordance with prediction caused by uncertainty of the project. Calculation by probabilistic method is rated better than deterministic since probabilistic includes the uncertainty factor in its calculation. In addition, probabilistic method provides results in the form of intervals in upper to lower limit. In predicting project's final duration, the time-based Earned Schedule (ES) method is rated capable of overcoming the lack of cost-based Earned Value (EV). This research aims to determine the ongoing project’s upper and lower limit prediction duration using ES method through validation towards the completed project’s real duration. The average prediction of ongoing project duration will be calculated using ES by Microsoft Excel. The results will be validated towards the average real project duration using hypothesis tests of two independent population means. Result of average of upper limits indicates a valid value while the average of lower limits indicates a non-valid value with the upper limit value is 0.0025 week/m2 and lower limit is 0.0020 week/m2.
Keywords: duration estimation; probabilistic; Earned Schedule; validation; upper limit and lower limit.
Abstrak
Penentuan estimasi penyelesaian proyek merupakan kegiatan yang berpengaruh dalam proses perencanaan karena dapat menentukan keberhasilan atau kegagalan proyek tersebut. Namun, durasi seringkali tidak sesuai dengan prediksi karena sifat ketidakpastian proyek. Perhitungan dengan metode probabilistik dinilai lebih baik daripada deterministik karena metode ini menyertakan unsur ketidakpastian dalam perhitungannya. Disamping itu, perhitungan probabilistik menyajikan hasil dalam bentuk interval yang dinyatakan dalam batas atas dan batas bawah. Dalam memprediksi durasi akhir proyek, metode Earned Schedule (ES) yang berbasis waktu dinilai mampu mengatasi kekurangan Earned Value (EV) yang berbasis biaya. Penelitian ini bertujuan untuk menetapkan nilai prediksi batas atas dan batas bawah proyek yang sedang berjalan dengan metode ES melalui validasi terhadap durasi nyata proyek yang sudah selesai. Rata-rata prediksi durasi proyek konstruksi yang sedang berjalan dihitung menggunakan metode ES dengan bantuan Microsoft Excel. Hasilnya kemudian divalidasi terhadap rata-rata durasi nyata proyek yang sudah selesai menggunakan uji hipotesis rata-rata sampel ganda. Hasil nilai batas atas proyek yang sedang berjalan dinyatakan valid dan nilai batas bawah dinyatakan tidak valid dengan nilai batas atas sebesar 0,0025 minggu/m2 dan batas bawah 0,0020 minggu/m2.
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