عنوان مقاله [English]
In order to transfer risks to the most capable party and provide a basis for project profit sharing, risk allocation has a strong influence on the time and cost of construction projects. In this paper, for the first time, allocation of
risk to the most deserving party is defined as an optimization problem, and a quantitative model for risk allocation optimization is introduced. Since the aim of risk allocation is defined as achieving project objectives with maximum
reliability and minimum cost, in the proposed model, an applicable and logical decision parameter is introduced and an optimization algorithm, based on the Ant Colony Optimization (ACO) method, is developed. The proposed model also provides a useful decision tool for the project owner to select the best insurance package by including a sensitivity analysis.
In order to design the ACO optimization algorithm of the risk allocation optimization model; initially, the objectives of owners within the allocation process are identified and the objective function is defined. With respect to
the objective function, the risk allocation problem is then restructured as an optimization problem, and the decision parameters, constraints and a flowchart of the model structure are defined. These parameters and constraints are formulated in a mathematical equation; and an optimization algorithm is designed based on Ant Colony Optimization (ACO).
By receiving profit requested for risk bearing by each participant as input, the proposed model calculates the cost of risk management for the owner and then minimizes the objective function in an Ant Colony Optimization
algorithm. Two constraints are defined and formulated in the proposed model, in order to simulate the real decision process of risk allocation. As follows: 1) the maximum financial credit of each party to compensate the consequence of any risk and 2) the financial ability of the owner to ensure against risk events.
Varying this constraint, sensitivity analysis would be available in the model to optimize the guarantee package for the owner. Therefore, this model could guide the decision maker towards addressing the most effective guarantees to the best party.
This model is applied in a case study to present its capability and usefulness. According to the findings of the applied proposed model, it could be concluded that risk sharing in a project should be done based on party competency and willingness. It is also concluded that the owner should participate in the risk allocation process if he/she wishes to achieve the best reliability in project objectives with minimum cost.