|Pilot Job. Federal courthouse building information modeling is called positive and negative. |
(Image courtesy of H3 Hardy Collaboration Architecture LLC)
“We’re at the kick-off meeting for a great project. All the players are present. The surfaces of the room are filled with digital screens, caves, images (think Tom Cruise...Minority Report). The group can see and access all project data compiled to date to get a jump-start. We begin to use BIM on day one, by capturing goals and expectations, developing and validating program and scope. We gut-check the budget and even begin to generate project and systems options in 3D, 4D and 5D. Everyone on the team sees this integrated data live as we generate it. With immediate consensus and no time lag waiting for meeting notes, we get done the equivalent of an entire phase in a day or two.
“After a BIM-enabled social team-building session, we resume the next steps and evolve the BIM through what used to known as ‘phases.’ We use it throughout the entire concurrent design, construction and commissioning process.
“With the time saved from submittals, review and rework, we finish early and under budget. The owner moves in, we deliver the digital asset for facilities management and celebrate with a weekend on the owner’s yacht.”
This particular building information modeling (BIM) utopia is in the mind of Michael LeFevre, director of planning and design support services for Holder Construction Co., Atlanta. But LeFevre, an architect, thinks his perfect project scenario may actually happen by 2020.
That’s because a revolution is beginning in the buildings sector and the catalyst is computer-enabled BIM. The coming kinder, gentler BIM business models are expected to produce better buildings, faster, at lower cost, with fewer claims and less agita. BIM technology “will not only change the existing delivery systems, it will change the job description of most people involved in design and construction,” says Barbara Heller, CEO of Design + Construction Strategies, a new BIM consultant in Washington, D.C.
The paradigm shift is creating BIM angst. To minimize it, “you need to start with realistic expectations and align the implementation of BIM technology with your core business objectives,” says Rodd Merchant, quality assurance-BIM manager at JE Dunn Construction, Denver. “Start small and add complexity as you gain confidence,” he says. “Resist the urge to do it all.”
The entire building team, from the owner on down the food chain, is grappling with how to make the best of BIM. Help is on the way. The National Institute of Building Sciences is creating a National BIM Standard (NBIMS), set for publication by year-end (see related story). The federal General Services Administration is publishing the first part of a guideline for 3D and 4D (the dimension of time) BIM, due out in August. The American Society of Civil Engineers and the American Council of Engineering Cos. are holding BIM workshops and BIM strategy sessions for structural engineers. The first is June 22, in Chicago.
|+ Enlarge this chart|
|BIM Poster Project.�On the Denver Art Museum job, there are coordinated design and construction models rather than a single digital model. |
(Image and chart courtesy of M.A. Mortenson Company)
The list of organizations on the BIM parade keeps getting longer. Even the American Institute of Architects, viewed initially as reluctant about BIM, is defining a “new vision for practice” based on BIM and integrated practice that involves constructors, says Norman Strong, a partner in Seattle-based Miller/Hull Partnership LLP and chair of the AIA’s 15-month-old integrated practice strategy work group. AIA also is creating model “digital” documents, expected to be available next year.
The consensus is that BIM, if used properly, is the greatest thing since sliced bread. But during the transition to BIM, as with any paradigm shift, design and construction firms are not only figuring out new business models, they are still doing things the old way. That complicates issues.
People have yet to agree on fundamentals, such as a BIM definition. A definition is important because “many architects feel they cannot begin to use building modeling until there are entirely new delivery methods, contract relationships and insurance mechanisms in place,” says E. Davis Chauviere, chief information officer for architect-engineer HKS Inc., Dallas.
GSA, which will require some level of BIM in its fiscal 2007-funded projects, defines BIM as “a digital model of a building at a given point in time.” The National Institute of Building Sciences defines it as a “digital representation of physical and functional characteristics of a facility. As such it serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life cycle from inception onward.”
Few would argue that BIM is a potentially great tool for planning, design, analysis, system coordination, fabrication, construction and facilities management. BIM-based project delivery, even in an immature stage, is “much more intelligent” than the traditional, 2D process based on plans, sections and elevations, says Jeff Millett, director of information and communications technologies with Stubbins Associates Inc., a Cambridge, Mass.-based architect.
Some say there will eventually be a single BIM, managed by the architect or the constructor. Others see multiple design models integrated into one by the architect and multiple construction models, integrated into one by the constructor. Each entity will have a model keeper to coordinate design and construction models.
BIM works best in a collaborative rather than adversarial atmosphere. Jim Jonassen, managing partner of architect NBBJ, Seattle, envisions a process in which design and construction phases overlap, with appropriate team members taking the lead in different phases, with participation by other players (see drawing, below).
|+ Enlarge this chart|
BIM is more difficult with a traditional design-bid-build delivery system. “Usually, once bids are in hand, the client wants to start building,” says Dale Stenning, operations manager for Hoffman Construction, Portland, Ore. “If subs that typically generate construction data aren’t on board [before construction], there isn’t much time to produce a fully coordinated construction model.”
BIM is “definitely reshaping roles and responsibilities downstream of the architect,” says Derek Cunz, director of project development in the Denver office of M.A. Mortenson Co. The firm is almost finished with the Denver Art Museum, using BIM (ENR 5/15 p. 26).
|Transition. Designers begin to get up to speed on software to produce 3D digital models. |
(Rendering courtesy of M.A. Mortenson Company; Drawing courtesy of Studio Daniel Libeskind and Davis Partnership Architects; Illustration by Guy Lawrence for ENR)
An area of concern to designers is technology. BIM software is unfamiliar to many and cumbersome to use when changes need to be made, say users. “The transition from 2D CAD to 3D modeling is far more challenging and difficult than the transition from manual drafting to CAD” that began more than two decades ago, says HKS’s Chauviere.
In a survey of architects, being released this week, 74% of respondents said they use some form of 3D modeling/BIM (see sidebar, below). But the survey does not indicate how many are sharing 3D models with constructors. Many maintain that if a BIM is given to the contractor, design decisions have to be made earlier in the process. That could be an issue.
For the structural engineer, BIM requires “dimension discipline” not required for 2D contract documents. Subcontractors rely on accuracy for detailing and running computer numerically controlled fabrication equipment.
It suddenly matters whether the top of a column footing is 12 or 15 in. below the finished floor. “On a BIM project, an engineer who ignores that difference could create a situation where the foundation is 3 in. too high,” says Clifford Schwinger, quality assurance manager for structural engineer Cagley, Harman & Associates, King of Prussia, Pa.
On fast-tracked projects, the structural engineer often does not have enough information to provide a certified model on which downstream consumers of the design—fabricators, detailers, erectors and so on—can rely, contractually and
for shop drawings. Further discussion in the industry about balancing contractual risks and rewards is needed to fully capture the potential of BIM de-livery, sources say.
Structural engineer Thornton Tomasetti (TT) isn’t letting the need for accuracy get in the way of steel BIM on fast-tracked jobs. On these, to get a mill order in early, “we are generating sections of the structure [in a BIM] and issuing the model...