Development of an Automated Workflow for Reinforced Concrete Structural Quantity Takeoff and Cost Estimation Using Visual Programming in a BIM Environment

In the construction industry, traditional quantity takeoff (QTO) methods still rely on manual measurement from 2D drawings, which are time-consuming, prone to human error, and difficult to verify. As Building Information Modeling (BIM) adoption grows, especially following the release of national BIM standards in 2020, there is increasing interest in developing automated and data-driven workflows to improve the accuracy and efficiency of material quantity estimation. This study proposes an integrated workflow for the automated quantity takeoff and cost estimation of reinforced concrete structures using BIM and visual programming. The workflow leverages Dynamo in Autodesk Revit to extract structured rebar and concrete data from BIM models, which is then exported to Excel using VBA macros for sorting and cleaning data and visualized in Power BI dashboards. A case study of a 7-story residential building demonstrates the application of the proposed workflow. Results show a significant reduction in processing time from several hours using manual Revit QTO to just a few minutes while maintaining high accuracy, standardization, and traceability. The dashboard allows multi-dimensional analysis by material type, structural component, and building floor, supporting effective decision-making in construction cost management. The findings point out the prospects for scalable deployment of this workflow in digital construction environments.