Evaluation of Selection Algorithms for Simultaneous Layout and Pipe Size Optimization of Water Distribution Networks

In this paper, a genetic algorithm is presented for the simultaneous layout and pipe size optimization of water distribution networks and its e ciency is evaluated and compared using di erent selection mechanisms. An engineering concept of reliability is used, in which the number of independent paths from source nodes to each of the demand nodes is considered as a measure of reliability. The method starts with a prede ned layout, which includes all possible links. The method is capable of designing a layout of prede ned reliability, including tree-like and looped networks. It is shown that a layout optimization of a network, followed by size optimization, does not lead to an optimal or a near-optimal solution. This emphasizes the need for simultaneous layout and size optimization of networks, if an optimal solution is desired. The performance of the method for layout optimization of pipe networks is tested against two benchmark examples in the literature and the results are presented.