By William McCallion, AIA, LEED AP, Manager of Quality Control & Training
The emerging technology of BIM (Building Information Modeling) holds the prospect for a paradigm shift in the way buildings are designed and built. Enabled by the increasing availability of greater and cheaper computing power, Designers and Contractors are more empowered to record their visualizations to greater and greater degrees. BIM is one of the outcomes. Simply put, BIM is a virtual 3-D model of the building; however, it doesn’t stop there. In addition, there is, also, 4-D and 5-D, which is basically attaching information such as scheduling and costs to the model. (I think physicists might have a problem with that labeling.) Furthermore, other programs, such as daylight or energy studies, can plug into the model. The 3-D model is “smart.” Whereas in a 2-D environment, lines represent walls, in a BIM model those lines “know” they are walls. A wall that realizes that a window size has been changed, for example, can then direct the other related aspects of the model to change in kind. This is a significant advance.
With these tools, it is, in essence, possible to “build” an entire building virtually before a shovel goes into the ground, knowing its cost and schedule. One of the unique features of BIM is in the coordination of disciplines. Previously, the Designer of Record would be responsible for assuring that there are no conflicts between, let’s say, where a duct runs and where a beam runs, a tedious undertaking to say the least. BIM automatically presents such “crashes” to the Designer in real time, saving time and effort. Knowing virtually every aspect of the building prior to its construction has the possibility of eliminating unanticipated change orders, the bane of many a project’s budget. This information is usable throughout the life cycle of a building, particularly in the facility management cycle, in a way the drawings have not been.
However, the real shift is the way that the information gets into the model. When Brunelleschi won the competition for the Duomo in Florence, he was not only the Designer but also the Master Builder directing the construction of the building. In modern times, these tasks have been specialized, separating Architects from Contractors, with Architects disavowing responsibility for the means and methods of construction and Contractors disavowing any responsibility for design. A body of law and insurance policies has evolved to service this methodology. However, now that we have the technology to put information from both sides into one vehicle, a new relationship needs to evolve. The AIA (American Institute of Architects) has termed this relationship the Integrated Project Delivery (IPD) method. In essence, the Contractor (and in many cases a specialty subcontractor) joins the Architect during the design process providing information (such as cost and scheduling) for the model. The advantage is obvious, as the Architect can incorporate changes to the design based on the information the Contractor has provided. There is no need for “value engineering” at the end of the design process because it was done in real time during the design. The AIA has established new contracts to reflect this change; however, as this technology is still emerging, more will be revealed, and a body of law and insurance policies will need to evolve. And what might the future hold? One vision is that the model will be directly connected to fabrication facilities so that the model can order the components it needs when it needs them; we’ll see.