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Mathematical Problems in Engineering
Volume 2016, Article ID 3264214, 11 pages
http://dx.doi.org/10.1155/2016/3264214
Research Article

Algorithms for Pallet Building and Truck Loading in an Interdepot Transportation Problem

1Department of Mathematics, University of Castilla-La Mancha, Avenida de España, 02071 Albacete, Spain
2Department of Statistics and Operations Research, University of Valencia, Doctor Moliner 50, Burjassot, 46100 Valencia, Spain

Received 15 December 2015; Accepted 15 March 2016

Academic Editor: Paolo Maria Mariano

Copyright © 2016 Maria Teresa Alonso et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper deals with the problem of a logistics company that has to serve its customers by first putting the products on pallets and then loading the pallets into trucks. Besides the standard geometric constraints of products not overlapping each other and not exceeding the dimensions of pallets and trucks, in this real problem, there are many other constraints, related to the total weight of the load, the maximum weight supported by each axle, and the distribution of the load inside the truck. Although the problem can be decomposed into two phases, pallet loading and truck loading, we have taken a combined approach, building and placing pallets at the same time. For each position in the truck, a pallet is built and tailored for that position according to the constraints of height and weight. We have developed a GRASP algorithm, in which the constructive algorithm is randomized and an improvement phase is added to obtain high-quality solutions. The algorithm has been tested on two sets of real instances with different characteristics, involving up to 44 trucks. The results show that solutions with an optimal or near optimal number of trucks are obtained in very short computing times.