For the arena facade, SHoP Architects hired SHoP Construction for constructibility reviews, automated quantity takeoffs for exterior materials and model integration with EB's and TT's building systems.

To develop the surface geometry to study initial forms, the architect used software called Rhinoceros, a stand-alone 3D modeling tool developed by Robert McNeel & Associates. When SHoP identified the final form, it switched to CATIA, a multiplatform CAD/CAM software suite developed by Dassault Systemes.

Hunt awarded the $32.4-million exterior-wall contract to ASI in February 2010. Soon thereafter, SHoP Construction became a subcontractor to ASI to detail the pre-weathered steel panels.

SHoP also developed a 3D model that would enable ASI to fabricate the panels using computer-numerically-controlled equipment, without creating its own BIM.

"If we could sequence and control information [digitally], the facade contractor didn't care how many unique panels there were," Mallie says.

Rely On It

TT's use of BIM facilitated the entire job, starting with the structure. For the work, TT gave the steel fabricator its Tekla Structures model and said, "Rely on it," says Scarangello.

"We used TT's unconnected model," says Chet McPhatter, chief operating officer for the Lynchburg, Va.-based fabricator Banker Steel Co. "This is very rare on a project of this type and is a viable option if the engineer is good at detailing."

On the arena in general, thanks to the model-sharing, the approval process was 50% faster than normal, says McPhatter.

Hunt already had bid the foundation and steel packages, when FCRC introduced the new facade scheme. The new steel had to be added.

BIM-sharing allowed Banker to quickly add the facade steel to the mill order and the steel package. "It just took a lot of work," says McPhatter.

On the west side of the building, the halo extends about 20 ft above the roof surface and 20 ft away from the face. To support these, TT cantilevered roof columns beyond the roof. A system of horizontal girts spanning between trussed vertical frames supports the lattice and attaches back to the cantilevered columns.

The canopy is supported by a network of steel trusses. Pairs of cantilevered trusses are laced together to create box trusses north and south of the canopy opening.

To achieve the long cantilever, the backspans of the box trusses—12.5 ft deep at supports and 9 ft, 10 in. deep at the tips—extend 100 ft into the arena, above the west entrance, to engage the arena bowl's primary columns. Another box truss spans 120 ft across the west tip of the structure. At the east side of the opening, three cross-trusses skewed in plan frame out the east face of the opening.

To limit fieldwork, Banker added SHoP Construction's facade connections to its shop drawings and installations.