INVESTIGATING THE PRECISION OF QUANTITY TAKE-OFF IN BIM APPLICATIONSن

An accurate material quantity take-o and estimationare vital issues in various construction projects. Suchan accurate estimating and material quantity take-o isrequired prior to initiating a project for tendering andbidding purposes, and during the construction phasefor procurement and project control purposes. Thus,a number of Building Information Modeling (BIM) ap-plications have been utilized recently not only for ef- cient material quantity take-o and estimating pur-poses, but also for other construction engineering andmanagement commitments (e.g., visualization, clash de-tection, 4D 5D planning, and virtual reality). The mostcommon BIM applications can be named as \AutodeskRevit" and \Tekla Structures" for integrated modeling(e.g., structure, architectural, and MEP modeling) and\Autodesk Navisworks Manage" for site managementand 4D Planning purposes. In this research, the ac-curacy of automatic quantity take-o , using aforemen-tioned BIM applications, has been investigated. First,such an exercise is performed on simple steel and re-inforced concrete elements modeled using Revit struc-tural extension. Furthermore, this exercise is extendedto steel and reinforced concrete 3D structures, modeledin both TEKLA and Revit structures. By recognizingthe points of weakness of such BIM applications, somepractical recommendations are provided to enhance theaccuracy of automatic quantity take-o and estimation.Another side product of knowing the accuracy of auto-mated material quantity take-o is providing a realisticestimate based on the utilized estimating approach andemploying BIM software to avoid unplanned mistakes inestimating and quantity take-off.