GM’s Jack Hallman (from left) collaborated with Ghafari’s Samir Emdanat and Robert Mauck to create a 3D virtual design for GM’s plants. They are pictured with Elliott Farber of Equis Corp.

Perhaps Engineering News Record magazine said it best when GM launched into its 'virtual design' for the construction of its new auto plants. "General Motors Corp's World Wide Facilities Group (WFG) has taken the leap and rather than fall, it has flown," ENR reported in October 2005. "The GM staff who build the plants that make cars that roll all over the world decided to lock in plant designs as virtual models and then tell the contractors: 'Go build that!'"

Almost a year later, the team that is making the standardized design-and-build model work well appeared before the Global Innovator's Award judges' panel to demonstrate the innovation of their partnership and its output.

GM's Director of Manufacturing Construction, John Hallman, wasted no time getting right to the results. "Trust the model, and build to the model," Hallman relates. Trust is paying off in the form of fewer change orders per construction site, as well as a decrease in field rework. "There's been a 25% decrease in field bid project costs with no overtime" for a recently project in Flint MI, Hallman offers. Flint was one of five recent plant construction cases presented to the award judges.

Safety is another benefit, Hallman adds. There's less clutter of just-in-time materials delivery, and almost no overlap of subcontractors working on a given site at any time - all because the virtual design model details each phase of a plant's development, including exact specifications for all parts, pieces and materials, so that most everything gets done on schedule, on budget and right the first time.

Ghafari Associates is the partner behind GM that spurred creation of the "3D common process" that Hallman says is "repeatable, sustainable and growing."

Bob Mauck, VP of Advanced Technologies for Ghafari, describes the firm's product on behalf of GM as a "Building Information Model," or BIM. For example, BIM has helped GM accelerate the delivery of structure steel from 10 weeks to 10 days, Mauck points out. "It eliminates reworks from the supply chain stream from master footprint to detailed model, then enhances availability and use of steel materials, and even extends to piping and sheet metal. The 'value stream' benefits all the trades involved in building a plant."

The paperless system updates project and supply data in real time. It also features an 'automated collision detector,' as Mauck terms it. "The automated collision detection allows architects and engineers the opportunity to view in 3D any interferences that would occur between various building systems, such as electrical bus lines, structural beams and HVAC and plumbing systems."

Another upside, according to Mauck, is that 3D virtual design "carries over project information across the entire timeline and life cycle of an asset."

Hallman points to senior management at GM, which is happy about the new approach. "Executives are convinced that the use of 3D BIM catapulted their facility lean efforts toward manufacturing levels of efficiency in delivering products and facilities faster, better, at a lower cost, while creating a safer and greener work site."

He offers metrics that fall along those lines:

• 26% faster delivery for customer end-use
• Bi-directional data transfer: design to fabrication/install
• Structural steel mill order: 3 weeks
• HVAC install 4 weeks ahead of schedule - no field rework

• 3D "as-builts" before construction including space protect for future equipment and maintenance
• No $$ change orders from building interferences
• Request for Information's (RFI's) reduced by 50%
• Improved trades morale with less tear-out
• Drawings extracted from 3D model

• Value engineering decisions earlier using full-discipline 3D schematic model
• Owner changes: < 25% of typical Design/Build project
• Virtually no field overtime
• Zero change orders from interferences/coordination: 5+ % savings in first cost

• Increased off-site fabrication supports:
• Reduced scrap material (sheet metal from 20% to 0%)
• Reduced lay down areas
• Less job site clutter
• Better trades coordination & sequencing (less trades overlap)
• Fewer lifts on-site and in building at same time
• Install once: rework minimized/eliminated

• Reduced scrap: exact Bill of Materials from 3D model data (avoids over-order)
• Off-site fabrication and just-in-time installation
• Reduced site disturbance: lay down areas minimized with off-site fabrication
• Reduced energy use and emissions with shorter construction schedule, minimized overtime, reduced transportation for: incoming materials, outgoing dumpsters, construction workers and on-site construction equipment

How did virtual design and BIM move to the forefront of GM practices? GM simply took a page from its own learnings about CAD-based virtual design of cars themselves.

"This was an initiative to bring the same waste eliminating and lean 3D math-based advantages to construction that our product colleagues had achieved for vehicle development," Hallman comments.

A Construction Industry Institute study shows that waste currently accounts for 26% of the manufacturing value stream vs. 57% of the construction supply chain, to which Hallman reacts, "After pioneering the techniques with the Design/Build team over multiple projects, GM WFG executives are convinced that the use of 3D BIM catapulted their facility lean efforts toward manufacturing levels of efficiency in delivering products and facilities faster, better, at a lower cost, while creating a safer and greener work site."