As Building Information Modeling (also known as BIM) has moved to the forefront of the construction industry, the architecture, engineering and construction (AEC) community has begun to ask the question: What’s so great about BIM and how is it going to help my bottom line? Here at ESD, as we have begun the implementation of Autodesk’s BIM software Revit, this question has been brought up constantly by designers and project managers alike. We’ve all been told that BIM is the answer to our problems: it will speed up the design process, eliminate many coordination issues between trades that are often left to be dealt with during construction, and, ultimately, save everyone involved in the project money. But how do we know it’s the answer?
So, we decided to do a little experiment: use Revit for the design of a fast-paced project and, at the end of the project, compare the as-built conditions with the BIM model. This would be the ultimate test – does BIM really speed up the design process and, by doing coordination in the model during design, will using BIM help eliminate issues during construction?
The project chosen was the Hillshire Brands Downtown Chicago Headquarters. It was an ideal project for this type of experiment. The as-built base building conditions had already been modeled by the base building contractor using BIM software, the interiors architect (Perkins & Will) and lighting designer (LightSwitch Architectural) would be modeling the interior portion of the project using Revit Architecture, and we would be using Revit MEP to model the mechanical, electrical and plumbing systems. The entirety of the building would be modeled using BIM, so what better project to use to compare to actual building conditions?
The first test was to see if BIM really did speed up the design process. While, in essence, The Hillshire Brands Headquarters was a typical interiors build-out: 250,000 s.f. of general office space with some specialty areas, including two test kitchens and conferencing space on the upper floors, what made this project unique was the timeline. Because of a tight construction schedule, the engineering design team had six weeks to complete Bid and Permit documents from the time P&W issued the architectural model for engineering. A normal project of this scope and magnitude would have a design schedule more in the realm of 8-10 weeks. Because of our ability to coordinate with all trades, including structural, architectural, and the MEPFP within our own firm using BIM, we were able to produce a complete, quality set of drawings within this tight timeframe. BIM had passed the first test – it did, in fact, speed up the design process to allow us to meet a deadline that, under any other circumstances, seemed impossible.
Next, it was time to test if all of the coordination done during the design process had paid off. We planned on doing this by selecting specific locations throughout the space, taking “snapshots” of the Revit model at these locations, and comparing them to actual photos taken of the space once construction was complete. The following were our results:
The locations of where “snapshots” were taken, both in the model as well as in the actual space.
Location # 6
As can be seen in the side by side comparisons, what was shown on the construction documents is almost identical to what was installed in field. Considering the speed at which both design and construction necessitated in order to complete the project within the required timeframe, it is amazing that the result ended up so close to the original design. In fact, based on the number of Requests for Information (RFIs) from the contractor and coordination required in the field (or lack thereof), it appears that BIM has passed the second test. In the end, by allowing so much coordination between trades to be done on the front end, we were able to avoid major discrepancies in the field, allowing the project to be built as designed.
So let’s go back to the initial question: What’s so great about BIM and how is it going to help my bottom line? At the end of the day, the use of BIM allowed us to complete a project under a seemingly impossible schedule, while at the same time allowing coordination on the front end to help prevent discrepancies in the field.
Many in the AEC industry are approaching the implementation of BIM with hesitation. And while this is a seemingly appropriate response to have toward the use of any new software, it does appear that BIM, along with associated programs like Autodesk’s Revit, just may be the answer the industry has been looking for.