Cost-Time Model for Large CPM Project Networks

A simple and efficient algorithm for hand computations or computer solutions is presented for developing cost-time trade-off curves for CPM project networks. The use of such curves, whose importance as project management tools increases with network size, has been hampered by two factors: the shape of cost-time relationships for the project's activities and the excessive computational costs for large networks. This algorithm is especially designed to cope with the above difficulties. All large engineering project networks can be decomposed into nonoverlapping segments so structured that their cost-time curve can be computed efficiently. Replacement of these segments by equivalent arcs drastically reduces the network either to a single arc, whose cost-time curve is the project-cost curve for the original network, or to a small nondecomposable form whereupon other existing schemes can be employed.