formation of the historic steam plant to a 124,000-square-foot office building posed numerous challenges. Inside the steam plant shell, a new four-story office space was created that utilized the existing roof and existing north, south, and west masonry walls to enclose the space. The footprint of the office building, however, extends outside the original steam plant walls toward the Maumee River on the east. Structural steel was utilized for the architectural desired openness of the headquarters, with most of this steel being exposed. The floor plan inside and outside the steam plant walls consists of large bays (50 feet by 32 feet) to maximize column-free office space. These bays were only possible using wide-flange steel composite beams with up to 2 inches of camber. These beam cambers were closely monitored while pouring the composite floor slabs (3-1/2-inch normal-weight concrete on 3-inch composite deck). Three-inch composite deck was utilized to reduce the quantity of steel pieces, reduce tonnage, and to create the minimalist industrial feel to match the history of the site. Floor-to-floor heights were also limited by the existing steam plant height, thus the majority of the floors utilize beam depths of 24 inches or less. The existing steam plant utilizes pairs of steel lattice columns at roughly 16 feet on center, which support steel roof trusses that span approximately 71 feet, 8 inches between the east and west walls. The lattice columns are set inside the existing masonry walls. Structural engineer is HKS, Inc., Dallas. Hard Rock Stadium Shade Canopy Erection Plan, Miami Gardens, Fla. — Erecting a 14-acre structural steel shade canopy weighing more than 17,000 tons over an existing NFL stadium presented unique challenges
to the project team. Structural engineers Ruby+Associates, Bingham Farms, Mich., provided full erection engineering services to fabrica- tor/erector Hillsdale Fabricators. The canopy, designed by architect HOK and structural engineer Thornton Tomasetti, Washington, D.C., was part of a $500 million renovation of the 65,000-seat stadium. The canopy is supported by eight supercolumns. Transfer trusses spanning between pairs of supercolumns support a 350-foot-tall spire near each corner of the structure. Sixty-four structural cables, up to 5 inches in diameter and up to 300 feet long, extend from the top of the masts to suspend portions of the canopy. Ruby developed a steel erection plan requiring minimal shoring and no alterations to the existing sta- dium. A temporary falsework system was shoehorned into each corner of the stadium. The falsework system allowed for installation of the lower mast section and cross transfer truss. After these members were installed, the falsework was removed. To predict the construction stresses and deformations, as well as cable loading/deformation at each stage of erection, a sophisticated analytical model was prepared using SAP 2000. The SAP model accurately predicted the behavior of the extremely indeterminate structure, minimizing the number of costly and cumbersome cable readjustments. For more information about the IDEAS 2 awards and the winning proj- ects, visit www.aisc.org/ideas2.
Information provided by the American Institute of Steel Construction (www.aisc.org).
Research & Development Tax Credits Section 179D Energy Incentives Cost Segregation Studies
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