In modern project management principles, accurate estimations for construction duration are significant to successfully complete projects on time. However, it was determined that number of projects delayed within overall TOKI projects (2800) is the highest for housing projects (1530) by 25.71% while the number of housing projects delayed within itself was found to be 720 (47.06%). Therefore, it was decided to investigate the construction delays for only housing projects. The objective of this study was to reveal the significant difference between calculated construction durations by TOKIs own calculation method and durations indicated within the official construction contracts between TOKI as client and appointed contractors. This research adopts a case study methodology involving interviews with TOKI personnel. A report showing detailed project information about 2800 completed TOKI projects was obtained during the interviews. Interviews also showed that TOKI has been using three factors, namely number of houses, drawing type, and non-working days to calculate baseline construction duration. Findings of the study have shown that calculated construction durations by TOKI were way higher than of those indicated in official construction contracts. Comparison between construction durations by using TOKIs own calculation method and official construction contracts have revealed that TOKI was significantly shortened the durations while deciding official construction durations which ultimately led to many delays in the housing projects. In conclusion, it was suggested that a new model including additional factors affecting housing projects duration was necessary to predict construction duration more reliably and practically.
Anahtar Kelimeler: Project Management, Construction Time Planning, Construction Duration, TOKI, Case Study.