One of the main activities in highway construction is earthwork, that is a complex process involving excavation, transportation, and filling of large quantities of different earth material types.\ud Earthwork operations are costly, and undergo several constraints due to the fact that they have large environmental and social impacts on the areas surrounding the construction site. Using mathematical models to produce a minimum-cost earthwork plan that satisfies all constraints is thus of great significance for enhancing the productivity of the overall construction project.\ud This paper presents an earthwork optimization system based on the use of linear programming that operates in a novel two-phase approach. In the first phase an aggregate model determines the feasibility of the overall project, whereas in the second phase disaggregate models determine the actual flows of each material.\ud The two-phase quantitative method for earthwork optimization developed in this paper includes all features derived from the everyday activity of one of the major European companies in construction. It involves classical decisions such as excavations, fillings, use of quarries and dump sites, and the temporary rent of depots, but it also accounts for several novelties, including the use of recycling facilities and the explicit integration with the existing public road network. Extensive computational results are obtained by running the models on a set of realistic instances, and show the efficiency of the proposed approach in solving complex earthwork problems

In this paper, we present a decision support system (DSS) to optimize activities involving earth excavation, filling, hauling, recycling, and dumping in construction logistics projects. The system was designed through collaboration between operations research experts and a team at Strabag AG, an Austrian construction company. The DSS aids managers in scheduling construction activities by determining the amounts of materials that must be moved, purchased, recycled, and dumped in a given period, and by selecting paths that minimize the costs of performing these activities. Applying our DSS to the highway construction project, Autostrada Pedemontana Lombarda, has significantly improved the speed of decision making at Strabag AG and reduced its logistics costs by 10 percent. Our system, which is based on the use of linear programming, has two phases. In Phase 1, an aggregate mathematical model determines the feasibility of the project. In Phase 2, we execute a detailed model to determine the paths over which to move material in each period. We use graphical tools to visualize the model solutions and facilitate the decision-making process. The DSS, currently in use in several Strabag AG construction projects, is a powerful, flexible, and easy-to-replicate tool for solving construction logistics problems.

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