www.insightcore.com Journal of Buildings and Sustainability 1 2017 Vol. 2 No. 2 International Construction Projects’ Risk Cost Estimation: Fuzzy Logic and AHP in Application (Real Case Studies) Hesham Abd El Khalek a1 , Remon F. Aziz b , Hamada Kamel c a Professor of Construction Engineering and Management, Faculty of Engineering, Alexandria University, Egypt b Associate Professor of Construction Engineering and Management, Faculty of Engineering, Alexandria University, Egypt c PhD Candidate, Faculty of Engineering, Alexandria University, Egypt ABSTRACT A myriad of construction companies operating in the global construction industry aim at maximizing their profitability by shouldering international projects making use of such new attractive markets, and thus they reduce the dependency upon local markets. Due to the risky and uncertain nature of construction works, the company and project’s conditions should be accurately monitored; thus, the need to assess risk sensitivity of projects costs in a realistic manner arises. The comprehensive risk assessment is a method introduced as a decision making supporting tool through outlining a risk model that is, if applied, will aid the procedures of risk evaluation and prioritization of such projects, and assessment of risk contingency value. There are two approaches used for developing the risk model: first, the Analytic Hierarchy Process (AHP) which is applied for evaluating risk factors weight (likelihood); second Fuzzy Logic approach which is applied for evaluating risk factors influence (Risk consequences). Software aids were also employed to develop such model. The developed software has been proved reliable after having been applied on real construction projects. The outcome of using the proposed methodology and the tool of decision support for estimation of cost overrun resulting from risk has been proved reliable too, as it has been based on actual final reports on realistic projects. For the aim of the study, six case studies from varying countries were selected on the common basis of being actual projects. In these six cases the highest risk factors are determined, through applying the designed models, testing their results and evaluating risk cost impact. The proposed models in application showed that: the highest and lowest risk contingency of 49 % and 16 % were in Project no (5), (6) respectively in Egypt, where the projects no (1, 2, 3,4) in Algeria, Oman, Jordan and Emirates had risk contingency of 38%, 17%, 28 %, 40% respectively. The actual results are adjacent to those proposed in the program. Keywords: Risk Management, International construction, risk factors, Analytic hierarchy process (AHP), Fuzzy Logic approach, MATLAB software and Validation process. ____________________________________________________________________________________ 1. Introduction One of the factors resulting in cost overrun and delays of schedules in many projects is risk. The risk management effectiveness is a major aspect in project management (Ming and Hui 2003). We cannot rely on subjective judgement to determine the exact impact of qualitative decision factors on the project risk. yet we can only rely on it to constrain or exclude possible strategies for improving the qualitative decision. Considering participation in an international construction project required a thorough study of many dimensions simultaneously; for instance, project revenues maximization, project risks allocation and minimization, funds availability, etc. Thus, in order to assess the factors influencing the company’s analysis a multi factor decision making methodology should be applied (Dias and Ioannou 1996, Ludovic et al 2011, Antonio et al. 2011, John et al 2003). Due to the fact that there are many subjective and non-quantifiable parameters deeply affecting these decisions, they are extremely complex to make. Dias (1995) covered the issue of infrastructure projects evaluation from the perspective of contractors, and managed to reach main objectives of a risk model: 1. providing a logical, reliable and consistent process to facilitate a compa ny’s decision making to carry on with a project through analyzing different parameters, 2. Allowing the performance of a sensitivity 1 hamadakamel1974@gmail.com