محیط زیست و مهندسی آب (Jul 2016)
Optimal geometrical design of reshaping berm breakwaters based on minimizing administrative costs (Case Study: Farasakoo Breakwater)
Abstract
So far, many studies have been done to design reshaping berm breakwaters (RBB) that mostly have provided the effect of individual parameter on structure stability. Accordingly, the presentation of systematic optimal geometrical design of RBB is necessary. In this research, a generic program is presented to determine the optimal geometrical structure of RBB based on administrative costs. So, initially, the methodology were proposed to determine the breakwater optimal dimensions based on calculated berm recession from empirical formulae of previous studies and the cost of extraction and transportation of the materials from JAHAD and TOUSEH mines. The nominal diameter of stone blocks and the berm height from sea bed were selected as a decision variable based on sensitivity analysis. The results of implementation of the proposed structure using random search algorithm represent a significant reduction in costs of breakwaters construction compared to non-optimal values of decision variables. Based on the resulting optimal values, were determined the optimal percentages of extraction from miscellaneous mines with lowest extraction and transportation costs. The results indicated that the minimum cost is obtained if the values of nominal diameter of stone blocks and the berm height from sea be are equal to 0.82 and 4.9 meters, respectively. Therefore, the optimal width of berm recession was determined equivalent to 17.77 meters. Also, in order to achieve an optimal economic plan, the breakwaters constituent materials in JAHAD and TOUSEH mines must have 63.37 percentage with gradation of 1-2.5 tons and 61.71 percentage with gradation of 0.3-1.5 tons, respectively.
