Risk Assessment in Bridge Construction Projects by Using the Fuzzy Fault Tree Analysis

In this study, stoppage risk during fulfillment of some of the construction activities of bridge development projects is assessed with the purpose of identifying entire major effective reasons behind it, taking into account the appropriate risk mitigation strategies and determining the probability of mitigation strategies failure. To this end, the fault tree analysis method was employed, but adoption of the traditional method of fault tree analysis is very difficult or even impossible in many cases, including construction industry, due to limited access to the information. In this mode, fuzzy arithmetic operations which are computationally simple and do not require detailed experimental data can be applied as useful tools. In this study, the fault tree is first structured based on the results of Delphi method and survey of diverse sources. Then, using the fault tree analysis based on fuzzy logic, the probability of occurrence of the above-mentioned risk is computed. Finally, once the fault tree relating to risk mitigation strategies failure has been structured, major causes of strategies failure are determined. The data provided help managers of bridge development projects minimize increased costs and delay in projects and manage more effectively by eliminating or reducing the major causes of such risk.