Space and time allocation in a shipyard assembly hall

We present a space and time allocation problem that arises in assembly halls producing large building blocks (namely, a shipyard which assembles prefabricated keel elements). The building blocks are very large, and, once a block is placed in the hall, it cannot be moved until all assembly operations on this block are complete. Each block must be processed during a predetermined time window. The objective is to maximize the number of building blocks produced in the hall. The problem is modeled as a 3-dimensional bin packing problem (3D-BPP) and is handled by a Guided Local Search heuristic initially developed for the 3D-BPP. Our computational experiments with this heuristic demonstrate that excellent results can be found within minutes on a workstation, and that the heuristic outperforms a standard constraint programming approach. We also describe some additional real-life constraints arising in the industrial application and show how these constraints can be conveniently integrated in the model. ∗HEC Management School, University of Liège, Boulevard du Rectorat 7 (B31), B-4000 Liège, Belgium, [email protected] †HEC Management School, University of Liège, Boulevard du Rectorat 7 (B31), B-4000 Liège, Belgium, [email protected] ‡HEC Management School, University of Liège, Boulevard du Rectorat 7 (B31), B-4000 Liège, Belgium, [email protected] §Naval Architecture and Transportation Systems (ANAST), University of Liège, Chemin des Chevreuils 1 (B52-3), B-4000 Liège, Belgium, [email protected]