An optimisation model to increase the cross-dockings operational utilisation

Introducing a new version of a cross-docking assignment problem when forklifts carry bulk materials, we address an operational solution to reduce the impact of forklifts congestion in centre of terminals. We develop a mixed-integer bilinear programming model, a Tabu-search algorithm, where the main objective of the model is still to minimize the total transshipment costs, and additionally trying to minimize the weighted forklifts travelled distance (WTD) and the weighted unloading/loading labour costs at inbound and outbound doors (WLC). We hypothesize that longer WTD could shift the location of weighted forklift congestion concentration from the centre of the terminal toward the sides. We assuming four cost pattern's distributions, all are supposed to lead high flows to doors with low labour costs, which ultimately impact the total WTD, WLC, and TTC. The proposed Tabu-search outperform CPLEX by finding a set of a diverse and high-quality solution within a reasonable computing time.