İnşaat Proje Süresi Tahmininde Referans Sınıf Tahmin Yöntemi

Year 2018, , 1132 - 1142, 20.09.2018

Savaş Bayram , Saad Al-jıbourı

https://doi.org/10.19113/sdufenbed.469288

Cited By: 2

Abstract

Projelerde
yaşanan süresel gecikmeler, pek çok ülkede inşaat sektörünü ve diğer sektörleri
etkileyen küresel bir sorundur. Süresel gecikmelerin planlama
ve bütçeleme üzerindeki etkisi, ilgili tüm paydaşlar için ciddi ve çözülmesi
zor olmaktadır. Bu çalışmanın amacı, geçmişte tamamlanan benzer projelerin
gerçekleşen sürelerine dayalı olarak, kamu binası projelerinin süresel
tahminlerinin güvenilirliğini analiz etmektir. Bu amaçla Türkiye'de tamamlanan
643 kamu inşaat projesinin verileri temin edilmiştir. Proje verileri; sözleşme
süreleri, fiili gerçekleşme süreleri ve toplam inşaat alanlarından
oluşmaktadır. Bu verilere dayalı olarak güvenilir ve gerçekçi proje süresi
tahminleri üretmenin mümkün olup olmayacağını irdelemek için Referans Sınıf
Tahmin (RST) yöntemi önerilmiş ve kullanılmıştır. RST, kabul edilebilir
risklerin farklı seviyeleri için değişik referans sınıflarının fiili proje
sürelerini gerçekçi bir şekilde tahmin edebilen bir yaklaşımdır. Sonuç olarak;
Türkiye'de gerçekleştirilen kamu inşaat projelerinin sözleşme süresi öngörülerinin
genellikle iyimser veya olması gerekenden düşük olduğu belirlenmiştir. Doğru ve
gerçekçi tahminler üretmek adına, en yüksek ortalama inşaat alanına sahip olan
devlet binalarının, öngörülen proje süreleri üzerinden nispeten daha düşük
yükseltme değerlerine sahip oldukları tespit edilmiştir. RST yöntemi, önceki
çalışmalarda proje süresinden ziyade yapım maliyetini tahmin etmek için yaygın
bir şekilde kullanılmıştır. Bu çalışmada ise RST yönteminin bina projelerinin
süresel tahmininde kullanılabilirliği esas alınmıştır.

Keywords

Yapı, Proje yönetimi, Tahminleme, İş programı

Reference Class Forecasting Method in Predicting Construction Project Duration

Abstract

Project
delay is a global problem affecting construction and other industries in many
countries. Its impact on planning and budgeting can be serious for all
stakeholders involved and difficult to resolve. The purpose of this study is to
analyze the reliability of duration estimates of public building projects based
on actual duration of similar projects carried out in the past.Turkey is used
as a case study for this purpose and data from 643 public building projects
completed in Turkey were collected. The data include contract durations, actual
durations as well as the total construction areas for all projects. Reference
Class Forecasting (RCF) method is proposed and used to investigate whether it
would be possible to produce reliable and realistic project duration forecasts
based on such data. RCF can realistically predict the actual final duration of
the projects of different reference classes for various levels of acceptable
risks. Original estimates of the contract durations in Turkey are generally
optimistic or underestimated. Government buildings with the highest average
construction area required lower uplift values on the estimated durations to
produce accurate and realistic forecasts.So far the RCF method has been broadly
applied to predict project cost rather than duration. This paper describes it
use for forecasting duration in building projects.

Keywords

Construction, Project management, Estimating, Scheduling

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