BIM: automated quantity retrieval of expansion joints using revit & dynamo

Abstract

This project highlights a practical problem which I had experienced during my professional internship with a main contractor firm. Expansion joints are one type of building elements, normally used in buildings and roads to deal with the expansion and contraction of concrete slabs. They are normally represented by lines on construction drawings, with their descriptions included at the side in a text box. In times where the lines are not present on the drawings, a zone to place the expansion joints will usually be identified by the consultants. The exact locations are then decided by the main contractor, together with the expansion joint supplier. The problem experienced by the main contractor was that despite recent advances in building information modelling (BIM) tools, the process to obtain information about the expansion joints was still highly manual. While the consultant firm provided the building models in Revit and Navisworks, along with PDF drawings, expansion joints were not present in the models. Hence, a large amount of time was spent on drawing lines in PDF, measuring the distances in AutoCAD and PDF, and then tabulating these results in Microsoft Excel. These manual processes can be replaced by automated processes with the help of BIM software to save time on repetitive tasks and subsequently boost productivity. In this project, Revit families were created to enable easy incorporation of expansion joints into the Revit building model, and the automated process of retrieving the expansion joints’ data and information were carried out with customised Dynamo scripts, inclusive of some Python nodes. Data retrieved from the model were automatically tabulated in Excel and presented in a user-friendly manner. A 2-way link had been successfully created between the construction model and Microsoft Excel to facilitate the easy updating of data and information. This function is crucial in handling changes during the construction phase. Finally, a time cost comparison was done to establish the potential time savings of such an automated process. Potential applications and future improvements are also discussed in the report.