The answer is simple … the use of interoperable BIM technologies and methodologies has made structural steel the productivity leader in the construction industry. That may sound implausible, coming from an industry typically associated with terms like RFIs, re-submittals, change orders, and extras. Yet today structural steel projects are being completed with no change orders, no delays, and no claims and, in fact, with accelerated schedules and refunds to owners. What has changed? Technology-enabled collaboration has bridged the risk gap on structural steel projects.
Today’s technology allows a structural engineer to export 3-D structural design data into 3-D steel detailing software that can then export fully detailed 3-D steel fabrication data for direct digital download to CNC fabrication equipment. This ability to transmit digital data from one vendor-independent, off-the-shelf software application to another down the supply chain enables the virtual design and construction (VDC) of the structural steel frame of a building prior to its physical construction. Constructing a ”virtual prototype” of the structural steel framing system bridges the risk gap and avoids many of the problems associated with traditional delivery methods.
The structural steel industry realized interoperability in 1999 when it implemented CIS/2 (CIMSteel Integration Standard, Version 2) as the standard for exchange of electronic structural steel design and construction data among stakeholders along the structural steel supply chain. Achieving the widespread use of this technology and the sharing of data-rich 3-D object models was, and still is, however, the greater challenge.
The challenge lies in traditional design-bid-build practices where the structural engineer works for and through the project architect during the design phase and the remaining steel supply chain stakeholders (steel contractor, detailer, erector, material suppliers) come on board during the construction phase under the general contractor or construction manager. This traditional business practice, according to Patrick MacLeamy, FAIA, CEO of HOK Group, Inc., San Francisco, CA, leaves a risk gap between the design phase and the construction phase. MacLeamy, a 40-year veteran of architecture and the current chair of the International Alliance of Interoperability, is presently leading the charge for industry-wide adoption of ”buildingSMART” practices that promote the use of interoperable technologies and eliminate the inefficiencies inherent in traditional practices. The risk gap is created when 2-D drawings are used to communicate design information. Into the risk gap falls valuable information that never makes it from the design side to the construction side. Out of the risk gap come RFIs, change orders, and claims.
The steel industry is bridging the risk gap on projects with “steel teams.” A steel team is a legal entity often consisting of a structural engineer, a steel detailer and a steel contractor. The steel team contracts directly with the owner or general contractor to design and deliver the completed structural steel frame. The steel team shares data-rich 3-D object models.
The New York School Construction Authority (NYSCA) was an early beneficiary of the steel team concept with its three-school, 3,500-ton Glen Oaks School campus located in New York City’s borough of Queens. The NYSCA was under a tight 18-month schedule to get the school doors open for the September 2002 school year when they released 20 percent schematic drawings in April 2001. The steel team of South Carolina Steel and Cary Engineering, both from Greenville, SC, came on board under the design-build contractor, Leon D. DeMatteis Construction Corporation, Elmont, NY. The steel team relationship allowed the shop drawing preparation and approval process to proceed concurrently with the structural design effort during the construction documents phase of the project. Says EOR William Cary, P.E., “Data interchange between RAM and SDS/2 significantly reduced detailing errors” and “gave our engineers more confidence that their design was carried through.” It also resulted in “eliminating the need for time-consuming revising and resubmitting of shop drawings,” says Cary. The bottom line, as stated by NYSCA’s project officer Dean Johanson: “The fabricator’s coordination of the steel design and fabrication process brought us to where we are now — unpacking books, sweeping floors and waiting for the kids to start school!”
J.R. Barker, P.E., of Structural Consultants Inc., Denver, sees a similar problem with the traditional design-bid-build approach: “The one who pays for the documents is not the one who uses the documents.” Structural Consultants Inc. was part of the steel team on the recently completed, highly-publicized addition to the Denver Art Museum. The highly collaborative efforts of Barker and his steel teammates (fabricator Zimmerman Metals, Denver, CO, detailers Dowco Consultants, Burnaby, Canada, and Mile-High Detailers, Lakewood, CO, and erector LPR Construction Co, Loveland, CO) brought the 2,750-ton structural steel frame to completion three months early while giving $400,000 back to the owner. “The final 3-D steel detailing file was used extensively on-site by the general contractor and the erector to plan work and resolve erection issues,” Barker reports. The 3-D detailing model was also used extensively for coordination of building systems, resulting in avoidance of 1,200 interferences. R. Wayne Muir, P.E., the owner of Structural Consultants Inc. and a 30-year veteran of structural engineering, spoke approvingly of the steel team approach: “This allows us to be consultants again, not technicians.”
Another problem with traditional business practices is the reliance on 2-D construction documents as the deliverable. 2-D drawings require significant time and effort to create, review, understand and coordinate. And changes late in the design phase require even more time and effort revising, reviewing, coordinating, etc. One significant benefit of many of today’s BIM software tools is the parametric ability to produce 2-D drawings from the 3-D model. If the 3-D model is revised, the various 2-D drawing views are updated accordingly. According to Glen Birx, AIA, principal at Ayers/Saint/Gross Architects, Baltimore, “BIM allows the movement of many man-hours from drafting to design. Architects can spend more time designing, and less time drafting.” A/S/G switched their 40-person staff entirely to BIM starting in 2004. “… if the model is truly developed at the DD phase, then the CDs require less of an effort,” adds Birx. A/S/G did a manpower study comparing ‘pre-BIM’ to ‘post-BIM’. Reports Birx: “We have found that our average hourly rate has increased. But we also find that less total man-hours are required to do the same job.” This has allowed them to provide a better product for the same fee. And the most compelling message to designers from Birx: “The value of the model itself may generate additional fees.”
Perhaps Charlie Thornton, P.E., founding principal and chairman emeritus of structural engineering firm Thornton Tomasetti Inc., said it best to a room full of structural engineers at the recent ZweigWhite Structural Engineers Building Conference: “Get the steel contractor in the room ahead of time. Find out how much time will be saved. Have the contractor tell the owner to pay you [the structural engineer] more to save that time.” Thornton Tomasetti now has steel detailing capabilities in-house and has leveraged 3-D technology to great benefit on several recent stadium projects. Thornton suggested a simple formula of a one percent bonus to the structural engineer for every week of project schedule that is saved through providing the 3-D structural steel model to the steel contractor.
The BIG DEAL in the structural steel industry is not simply the technology of BIM. It is the technology-enabled collaboration that is boosting productivity and delivering structural steel projects faster, with greater value, while safely bridging the risk gap.
INFO: AISC (www.aisc.org)