An integer linear programming model for the multiperiod production planning of precast concrete beams

Unlike conventional beams, which are cast in the construction site, precast beams are cast in a production line in a beam factory. Their use may considerably reduce the completion time of construction projects, making them attractive to public housing. A key factor for the success of their use is the ability of efficiently producing them, which depends on the quality of the production planning. The objective of this paper is to propose an integer linear programming model for the precast concrete beams production problem. It is first shown that this problem is isomorphic to the well-known multiperiod cutting stock problem. The objective function is the minimization of the production loss of a production order, subject to the available capacity of forms used to cast the beams. A case study is presented with data of a real scale instance, so as to demonstrate the applicability of the model in industrial settings. The proposed model was implemented and ran on the CPLEX solver, which reached an optimal solution within an acceptable running time. The results indicate that significant gains may be achieved in terms of reduction of planning time through the application of the proposed model.