B2- Benefits for Contractors using BIM

Chapter 6 of the BIM Handbook was focused on the influence of BIM for contractors. Eastman first pointed out that the major advantages of using BIM technology in construction are saving time and money. These can be realized through the application of accurate building model and close contractor coordination by using BIM.

       From the chart “Construction Firms by Type Number and Percentage”. Eastman analyzed that a large number of contractors hire subcontractors for specialty services such as mechanical. electrical, and plumbing. The BIM can largely benefit on avoiding design errors and construction problems by the early integration of contractor and all subcontractors, especially in design-build firm when it responsible for both design and construction. Based on the close contractor coordination, subcontractors could integrate their own portions of work into one building model which provides a more direct way for clash detection. Instead of visually overlay 2D CAD layers to identify the potential conflicts in the construction, BIM-based clash detection could automatically check the conflicts based on the building model. It also “combined with semantic and rule-based clash analysis for identifying qualified and structured clashes” from Eastman’s expound. Home builders also take advantages from using BIM in design-build. If buyer change order, BIM can have a rapidly replay on quantity and cost change.

       In 2D or 3D CAD systems, contractors need to manually perform quantity takeoffs to provide the estimate cost and schedule, which waste a long period of time and could easily cost error. By using BIM, architects could provide design model in earlier stage, which contractors can use for estimating, construction planning, and so forth based on the detailed building information provided by architects. Contractors are also able to offer suggestions to contribute on the design when they could get involved in the design process. BIM software can easily use these information to track variance between budget and actual cost, and the project status.

       Eastman explained that “it is becoming more common for constrictors to fabricate components offsite to reduce labor costs and risks associated with onsite installation”. BIM can provide detailed component directly to fabricators, in contrast, it cost much longer time for contractor and fabricator to exchange information with 2D design, and the non-accurate information could highly rise the possibility of design error.

Reference:

Eastman, Charles M. BIM Handbook : A Guide to Building Information Modeling for Owners, Managers, Designers, Engineers and Contractors. 2011. http://web.b.ebscohost.com.ezproxy2.library.drexel.edu/ehost/ebookviewer/ebook/bmxlYmtfXzM2NDIzOV9fQU41?sid=2e33ff9c-0e60-47bb-98e7-5d58d37dc7a6@pdc-v-sessmgr02&vid=0&format=EB&lpid=lp_263&rid=0

Comments:

Nick Maloney:

It is great to see that REVIT can provide standard members and customized models to improve the design efficiency. However, we can not deny that it is still restrictions when transforming models and drawings between platforms. Standardization is a necessary step to go through this process, and it will help to simplify the automates exchanges, and increase the exchange speed.

Weiyi Tang:

I totally agree with you that BIM technology can be used to reduce the information gaps and communication conflicts between architecture and contractor. Furthermore, it well-cooperate with design-build, and allows contractor to get involved in the design stage and make suggestions, which highly increases the work efficiency and reduces design errors.

Richard Kimball:

Your post about competitions between platforms is very interesting to me. It is great to know some historical stories about how technology get improved through competition and integration. This is just like the products on shelf, if you want a better sales volume, your product needs to be evolved with the advantages of others. People say that “Children choose from two, but adult get both”.