4. The BUILDING PROCESS: construction requires many players and as a result is much more complex than, say, manufacturing or transportation. The construction industry is more fragmented and specialized than most any other field. Many firms collaborate on any given project, with varying degrees of success and profit.
A critical legal question to be answered before going ahead: Who owns the documents, BIM or otherwise? Who is benefiting and who is paying for this? BIM opens up many possibilities with respect to ownership and benefit from the "contract documents"... Contractors are experts in Cost estimating, Scheduling and Risk reduction: Does this change? If contractors receive a well developed BIM showing all the construction details, it's obvious that much of the coordination" on their end has been accomplished already. And once you have accurate and complete details of the design, what risks remain for the contractor to mitigate? In the end, the details of fabrication and the actual installation are the actual value added by a building contractor labor. Keep in mind that until now, the engineering and architectural services, including documents and Construction administration typically take up 4-10% of a projects total cost. The actual construction contracts take up most of the vast remainder. Will the contractors no longer bear the cost of coordination and shop drawings ? Will the engineers and architects receive compensation for the effort? How do we get compensated? These are questions that remain to be fully answered. The chart below shows how a BIM may change the work flow during design and construction.
At the winter 2007 ASHRAE meeting, I heard from an A/E firm in California that claimed that it had designed a hospital building using BIM, with 36,000 hours of billable time, and there were only 41 hours of "rework". They said they typically have 60% less RFIs and they have 60% completed construction drawings when the design development phase is finished. Some people are claiming even better results!
The groups worked until they established a standard called AECXml, (or Architecture, Engineering, construction Extended Markup Language) around 1999. This should not concern engineers directly, as it is data definition rather than the content we are concerned with. But it is helpful to know that this initiative was formed with the intention of making the various and sundry softwares work together, which is a core concept of building information modeling. Sharing data today
Sharing of cad drawings with other disciplines requires care. It requires knowledge and an appreciation for the complex system that a building is. (We know this as CAD setup)
Too often, multidiscipline sharing has a low priority. As Architects and MEP engineers, know all too well what happens when sharing breaks down:
Specifications are an area of BIM that gets little attention from the software developers and the press. Specifications are becoming integrated into the design drawings- heck, they are more important than the drawings contractually. Writing specifications could and should be simplified (theoretically )
Practicing engineers know that the critical information provided by specifications is a key document. Specifications enforce quality and the details as much as anything else in the contract drawings. Since we, as MEP engineers, must focus on quality, these specs must be a key aspect of a true Building Information Model.
Perhaps a BIM will actually help enforce high levels of information sharing among various consultants. BIM will (hopefully) make sharing automatic.
We will literally get on the same page as the architects: BIM will enable all the designers to accurately model, view and use the same up-to-date information. We may actually be working on optimal design rather than expedient solution.