Identification of Claim Paths Leading to Increased Costs in DBF Projects using System Dynamic Modeling Approach (A Case Study: Tehran Metro Projects

Summary Implementation of infrastructure projects in a country is one of the key issues in the country economic growth. However, increasing the claim in the projects is inversely related to the objectives of the project due to the lack of understanding of the factors that create it and the impact of its factors on each other, especially in underground projects that we involve with many unknowns. In this research, for identifying the claim paths in DBF Tehran metro projects, after the library studies and review documents, we determined the main factors of the claim. Then, the effect of the causation factors on each other was analyzed using the system dynamics method, and finally, the most important paths that led to cost increases were identified as a result of development of the system dynamics model.   Introduction Claims affect the performance of projects as recently seen in DBF metro projects. Researches have been made to reduce claims, but they are still prevalent. The reason is the need for a better understanding of claims in the projects. Once this understanding has been made, strategies can be put in place to prevent the claims. The system dynamics method as a complete tool for studying the behavior of complex systems can solve this need. Therefore, this approach in this research has been used to identify the claims of the contractor and financier consortium in DBF metro projects.   Methodology and Approaches Using library studies and semi-structured interviews with experts, as well as examination of documents related to actual claims of DBF metro projects in Tehran, 30 causes of claims were identified, and then, a questionnaire was used to identify and rank the most important causes of claim. Then, by re-interviewing with the experts and re-examining the data and documents, the causes of claim were re-analyzed using the systems dynamic method, and the causal model was developed. Then, 20 paths of claims were extracted from the model and a questionnaire was used to identify and rank the most important claims paths leading to increased costs in DBF metro projects.   Results and Conclusions The results of this research show that the significance of each claim is in relation to other claims. The causal relationship between the claims and the claim paths shows the role and importance of each claim. One of the most important paths is the mistake in delivering data to the contractor and claiming unpredictable physical conditions specific to underground projects.