Effects on duration and cost of change orders in public school construction projects

Public construction works run much more efficiently and effectively after the adoption of the Public Procurement Law No. 4734 in 2002. However, it is known that time and cost overruns are encountered in many projects based on design and construction. There are many factors in the field that cause time and cost overruns. In this study, a total of 141 change orders made during the design and construction phase of 85 public school construction projects, the construction of which was completed in the period between 2015 and 2019, were examined through change orders approval certificates, and the main and sub-reasons of the revisions were determined. The revisions that occur during the design and construction phases have been classified according to all the engineering and architecture branches involved in the process. It was emphasized that there have been revisions resulting from the feasibility, architectural, static, mechanical and electrical designs, and these lead time and cost overruns in the projects. The duration and cost increases caused by each branch were analyzed, and the frequency of the sub-causes and the impact on the project cost and duration were examined. In addition, a survey was conducted with the technical staff, most of whom were engineers-architects working in the public sector, in the study regarding the main and sub-causes causing the revision. In this way, it was aimed to elaborate the results related to the reasons for the project revisions obtained from the change orders approval certificates and to establish relations. At the end of the study, suggestions for solutions are also included to prevent revisions.