Posts tagged with "BIM":

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Fulton Street Transit Center Oculus

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An in-progress look at the new transit hub's massive skylight

After funding cuts and subsequent delays since construction started in 2005, the much-anticipated Fulton Street Transit Center is finally taking shape in Lower Manhattan. The $1.4 billion project will connect eleven subway lines with the PATH train, the World Trade Center, and ferries at the World Financial Center. In collaboration with artist James Carpenter, Grimshaw Architects designed the project’s hallmark—a 60-foot-tall glass oculus that will deliver daylight to the center’s concourse level. The hyperbolic parabaloid cable net skylight supports an inner skin of filigree metal panels that reflect light to the spaces below. AN took a look at the design’s progress with Radius Track, the curved and cold-formed steel framing experts who recently completed installation of the project’s custom steel panels:
  • Fabricator Radius Track
  • Architect Grimshaw Architects
  • Location New York, New York
  • Status Under construction
  • Materials Steel framing and decking, DensGlass sheathing, waterproof membrane, drainage mat, insulation, curved metal girts, Tyvek wrap
  • Process BIM, offsite fabrication
Metal framing was an ideal choice for the skylight’s large structure, whose 90-foot diameter required a high strength-to-weight ratio that couldn’t have been achieved with a heavier material like concrete. Cold-formed steel (CFS) could also be manipulated into the complex shapes necessary to achieve the skylight’s irregular shape. Though the project was originally designed as a stick-built structure, the design would have required workers to complete the construction of the complicated, sloping oculus walls while working five stories above ground. Proximity to the water raised concerns about severe storms that would have further compromised working conditions. The oculus also had to meet security standards surrounding the World Trade Center memorial sites, so the design team abandoned the stick-built approach and began to consult with Radius Track on an alternative construction method. The structure’s total surface area is approximately 8,294 square feet, comprised of 44 panels arranged in two tiers. Panel width is a constant 8 feet, while length ranges from 19 to 33 ½ feet excluding two smaller end panels measuring 4 feet by 14 feet. The knife-edge element at the top of the parapet is 167 feet long, with a profile that changes continuously along the diameter. Using BIM, Radius Track customized designs for the seven-layer panels that complete the walls of the oculus. The modeling software allowed the team to detect potential clashes within the panels and with other design elements early on, and also facilitated the rapid, offsite fabrication necessary for the project’s tight timeline. The custom panels are designed not only for performance but also for geometric precision. The seven layers include framing (studs, track, blocking, and knife-edge panels where applicable), steel decking, DensGlass sheathing (a drywall material used in exterior applications), waterproof membrane, drainage mat, insulation and curved metal girts to which exterior cladding is attached, and Tyvek wrap. While the materials used in the project are traditional, the methods to connect the layers are not. Each layer has its own particular pattern, making attachment details between the layers critical. (For example, the CFS layer is a grid, the decking consists of linear ridges aligned with one panel edge, and metal girts span across the panel.) Each layer required its own design and subsequent coordination to ensure the finished installation was as precise as possible. Several types of metal are used to create the oculus. The walls’ structural framing is 14 gauge (68-mil) cold-formed steel, a “beefier” design than Radius Track would typically employ because of high wind speeds and enhanced safety and security requirements that are now standard for government structures in New York City. Designers used 16-gauge CFS for the track that is wrapped horizontally around the oculus walls. Decking is VulCraft 3-inch steel decking and horizontal metal girts secure the insulation layers. At the parapet, Radius Track designed customized 16-gauge, laser-cut steel sheets to form the ever-changing slope that circles around the top of the structure. Some sections are opening to the public ahead of the anticipated mid-2014 completion, and the complex is eventually expected to serve 300,000 passengers each day with 26,000 square feet of new space that will also include new retail stores and restaurants.
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Trahan’s Louisiana Sports Hall of Fame and Museum

Cast stone and steel become the medium for collaboration at Trahan Architects’ newest project.

Trahan Architects’ Louisiana State Sports Hall Of Fame and Regional History Museum was designed with northern Louisiana’s geography in mind. Located in Natchitoches, the oldest settlement in the Louisiana Purchase, the 28,000-square-foot building overlooks Cane River Lake at the boundary of the Red River Valley. While the museum’s exterior will be clad in a skin of cypress planks, a nod to the area’s timber-rich building stock, the interior spaces will be formed by a skin of more than 1,000 cast stone panels resembling land shaped by eons of moving water. As the panels begin to be installed, AN went behind the scenes to learn how the project is taking shape.
  • Fabricators/consultants CASE Inc. (BIM manager and fabrication technology consultant), Method Design (geometry and steel detailing consultant), David Kufferman PE (specialty steel consultant), Advanced Cast Stone (cast stone fabrication)
  • Architect Trahan Architects
  • Location Natchitoches, Louisiana
  • Status Estimated July 2012 completion
  • Materials Cast stone, steel
  • Process Geometric resolution, structural analysis, steel detailing, BIM
Creating the building has been a largely collaborative effort. Texas-based Advanced Cast Stone will fabricate the stone panels, but the team involved in realizing the design also includes specialty steel consultant David Kufferman, steel geometry and detailing consultant Method Design, and Case, the firm providing the project’s fabrication modeling, BIM management, and technology consultation. Using Trahan’s 3-D documents, Case developed a set of customized automation procedures to create a final 3-D model with all of the stone panels, each with its own geometry. “If there’s not repetition with the panel typology, there can be repetition with the process of creating the files themselves and not necessarily the geometry,” said Case partner Ruben Suare. The firm’s software-agnostic approach allowed them to build the proper interface with a range of tools across ten different software packages. These models were used for structural analysis and coordination of all building systems, as well as for outputting shop tickets for use during fabrication. “This is an ideal situation for us because we are managing all 3-D information across the process,” said Case partner Federico Negro. They also created a clash-detection matrix to show where thickened panels would conflict with the project’s structural steel framework, to which the panels will be attached with embedded connections. Method Design served as a consultant to the engineer and stone fabricator to resolve these issues. “We basically had to develop tools to manage the tools,” said Method partner Reese Campbell, who previously worked with Negro at SHoP Architects. In all, Method designed 30 connection types for 1,150 panels, each with between 6 and 15 connections (each panel may attach with three to four connection types). Installation of the cast stone skin has begun and is scheduled for completion in the spring of next year, with an anticipated museum opening in the summer. Panels range in dimension from 2 by 2 feet to more than 15 feet square—the largest piece, to be installed on the atrium’s second floor, will weigh nearly 3 tons. Because panels are stacked in an offset-brick pattern, they must be installed in a specific order. “Not only is the finish of the piece important, its alignment with its neighbors and the grouting is important,” said Negro. “It’s a piece of sculpture.”
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Morphosis’ Museum of Nature & Science Facade: Gate Precast

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A new cultural focal point takes shape in Dallas

When the Dallas Museum of Nature & Science was created from the 2006 merger of three city museums—the Museum of Natural History, The Science Place, and the Dallas Children’s Museum—the new institution set its sites on expanding programming with a new facility in the city’s Victory Park neighborhood. Now, the 180,000-square-foot Morphosis-designed Perot Museum of Nature & Science is slated for completion in 2013. Located at the northwest corner of Woodall Rodgers Freeway and Field Street, it marks the future crossroads of the city’s Trinity River Corridor Project and the city’s cultural districts. Floating atop an irregularly shaped plinth that will be the base for a one-acre rooftop ecosystem, the museum’s striated concrete facade offers a first glimpse at the dynamic transformation of the site.
  • Fabricator Gate Precast
  • Architect Morphosis
  • Location Dallas, Texas
  • Status Estimated 2013 completion
  • Materials Precast concrete
  • Process Revit, BIM, concrete casting
Early renderings show a smooth monolithic cube as the museum’s main volume, but the Morphosis team began working with the Hillsboro, Texas, branch of Gate Precast early in the project to develop a horizontally striped precast concrete panel design for the facade. “They wanted something different from everything else in Dallas,” said Gate sales and marketing manager Scott Robinson. “The architects wanted it to be true, raw, and modern.” To this end, Morphosis selected a plain gray concrete mix, without pigment or white cement, for the facade, knowing there would be natural mottling to each panel. “They didn’t want the building to look painted,” said Robinson. In total, the company will fabricate 655 precast pieces for the project. Gate created a series of mock-ups using random combinations of convex and concave shapes that would flow seamlessly from one panel to the next. After refining the design in Revit, Gate’s BIM operators modeled more than 100,000 square feet of precast cladding on the museum’s exterior for Morphosis’ 3-D models. Wood-framed concrete molds constructed in a range of set dimensions (the average size is 8 by 30 feet) helped keep facade costs lower. Within these, convex and concave rubber pieces based on the team’s digital models can be placed to achieve the desired striation. In the harsh Texas sun, the random shapes cast bold shadows across the building’s elevations, gradually giving way to smooth concrete surfaces on the higher levels. Because the pattern continues at the building’s corners, end panels required a two-step process: The short end was poured and set first, then rotated to allow the long section to be poured before the two pieces were attached with a cold joint. The curved precast panels for the museum’s base created another challenge—building formwork in multiple axes. Gate’s engineering department created a series of geometric points and calculations for its carpentry wing, and carpenters built the formwork by hand without any CNC equipment. “The hard part is that they get a picture of what the panel looks like, and they have to build the reverse of that,” said Robinson. The curved precast panels will require nearly 80 unique molds in all, comprising about 15 percent of the project’s precast concrete. For its final contribution to the project, Gate will cast several pieces that Morphosis is referring to as “sticks”—long precast beams that will decorate the site as sculpture or functional elements once the new museum’s rooftop ecosystem, with landscape architecture by Dallas-based Talley Associates, is in place.