Accuracy of volumes from MX(moss) design software

Abstract

Earthwork volumes are one of the most important factors in the delivery of a major civil project. From when feasibility estimates are generated at the concept stage of a project, until when volumes become a vital component of the contractual agreements between owners and contractors it is essential they are within a reasonable range of accuracy. MX(moss) road design software is a commonly used program for major highway projects. It is generally assumed that volume errors are contained within the road design software used to determine these volumes. This paper will undertake analysis the accuracy of earthworks volume calculations from MX(moss). The approach taken was to take different simplified road profiles of a known volume and model hem in MX(moss). The mathematical and MX(moss) volume can now be compared and error percentages calculated. For additional analysis traditional and more complex MX(moss) triangulation volume techniques where used. Ranking of these results will unable different project management techniques to be applied and the risk to be accessed. The finding of the technical review of MX(moss) showed that different volume calculations do produce different errors. However to give the results some perspective in the delivery of a project some research of previous project management theory and qualitative analysis of senior road engineers and managers was undertaken. The survey results indicated some simple procedural items and changing trends in the industry to higher degrees of error being acceptable during construction. Overall the results where under the error limits defined for various stages of a project. The results from the above quantitative and qualitative analysis enables senior executives and governments making ‘go’ or ‘no go’ decisions during feasibility and contract administrators greater understanding of the errors and risks in there decision making. Feasibility stages of a project where high levels of accuracy are not needed, to the other end of the scale where high accuracy is need at the detailed stages of a project so managers producing cost plans and contracts can be better managed. The data presented in this paper reduces the risk for these people. Benefits from this study include reduced risk and achieving greater consistency within a design office. Recommendations in this paper could be used to form design checklists or part of a quality assurance system. Recommendations also include reference to developing a risk adverse culture where the risk of getting the wrong numbers is understood.