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Despite liability issues, A/E/C teams are benefiting from sharing their 3D models

By Michael Bordenaro

The deceivingly complex White Chapel benefited greatly from the creation of a 3D model by project steel fabricator A. Zahner, Kansas City, Missouri. Located at the Rose-Hulman Institute of Technology, Terre Haute, Indiana, the 5,000-square-foot chapel’s main structure is a series of 14 rectangular tube arches shaped like a 3D Gothic arch.

Bill Bradford, principal with Chicago-based VOA Associates, says, “The arches get smaller and shift off axis as you move toward the back of the structure. Viewing the computer model allowed us to realize that a rectangular tube connecting the top of the arches would provide limited bearing points for the decking.” A round tube section was specified to connect the tops of the arches and provide a more suitable point of contact for roof decking along the entire length of the structure.

The 3D computer model created in AutoCAD by Zahner also made it clear that the first arch, which tilts out over the entry, was substantially different from the others, even though no two arches are the same. “If we didn’t have the computer model, we may never have realized that the first arch is a parabolic arch instead of a circular arch like the others,” Bradford said. This information helped with detailing the curtain-wall facade of the chapel. Zahner, which also fabricated the White Chapel’s cladding system, used the computer model to help manufacture skylights for the building after no other company was found to effectively handle the complex geometry of the roof.

The renovation of Chicago’s famed Soldier Field and a master plan for North Burnham Park is a joint venture of the local firm Lohan Caprile Goettsch Architects and Boston-based Wood + Zapata, with the latter having primary responsibility for the stadium design. The new configuration of the stadium saves the historic colonnades by removing the interior seating structure, lowering the playing field, and inserting a new set of 63,000 seats and 133 luxury suites into the existing perimeter structure.

Joseph Caprile, AIA, says, “At some places, the new structural steel is within 2 feet of the existing building. We would not have been able to fit the new structure in as precisely as we did without 3D computer modeling.” Tony Montalto, project architect, had created some surface models of the project in Form•Z software to provide conceptual understanding of the design. He says considerable benefits were realized when structural engineer Thorton Tomasetti Engineers exported .dxf and .dwg files from its ProEngineer software for architectural review. “At some places, we have 10 to 20 pieces of steel coming together in complex connections. If we tried to detail this project in 2D, we would have ended up with problems,” Montalto says.

According to Montalto, another benefit of the steel-detailing software used on the project is the ability to create a database of parameters for creating connection details. “If a structural member type ‘X’ comes together with a member type ‘Y,’ the software can be programmed to establish a predetermined ‘Z’ type connection,” Montalto says.