A Study on the Factors Affecting the Economical Life of Heavy Construction Equipment

Surveys found that large contractors replace approximately 10% of their equipment fleet units annually in North America. Cost minimization model is a commonly accepted method for equipment replacement which helps to identify these equipment units whose total owning and operating cost reaches their minimum point as candidates for replacement. While the model is conceptually clear with the aim of achieving minimum equipment cost per unit of service, its use has some practical difficulties as the equipment maintenance and repair costs experience bumps and lumps in the its life time. In practice, identification of equipment units for replacement are still based on such metrics as limit of repair costs, limit of major failures, lessons learned from previous cases as well as expert knowledge. In this research, we look into the cost history of a large number of equipment units in a contractor’s equipment management information system (MIS) and use decision tree modeling approach to identify these factors impacting on the economic life of first hand equipment, and extract rules leading to different cost patterns and therefore different economic life spans of heavy equipment. C4.5 decision tree model is used to build a top-down decision tree by recursively splitting existing cases based on the concept of information gain. In addition to facilitating decisions in equipment replacement, the findings can also be used to explain the effectiveness of various maintenance strategies, compare the equipment cost performance among various classes, makes, and amount of services in their life cycle.