We’ve been on a steel kick lately, sharing the top steel bridges, top steel skyscrapers… But how about the best steel… Well, “things,” in the world? Not just one category, but the best new steel structures, period? The Building Design and Construction website covered just this subject very recently, with a list of their 2013 award winners in the subject, so it’s time to share their choices for the best new in 2013 steel structures!
Owner/Developer: City of Charlotte; NASCAR Hall of Fame, Charlotte, N.C.
Owner’s Representative: NASCAR, Charlotte, N.C.
Architect: Pei Cobb Freed & Partners LLP, New York
Architect: Little Diversified Architectural Consulting, Charlotte, N.C.
Structural Engineer: Leslie E. Robertson Associates, RLLP, New York
General Contractor: BE&K Building Group, Charlotte, N.C.
Steel Fabricator: SteelFab, Inc., Charlotte, N.C.
Steel Detailer: Hutchins & Associates, Clemmons, N.C.
Steel Erector: Williams Erection Company, Smyrna, Ga.
Bender/Roller: SteelFab, Inc., Charlotte, N.C.
Design-Build Contractor for Ribbon: Zahner, Kansas City, Mo.
Consultant: Ralph Appelbaum Associates, Inc., New York
Consultant: Jaros Baum & Bolles, New York
Photograph: Paul Warchol Photography Inc.
In approaching the challenge of designing a Hall of Fame for NASCAR, the project’s design team sought to capture the essential spirit of NASCAR and its sport in architectural form. In exploring the possibilities for expressing speed and spectacle, the team was drawn to the arena of action, the racecourse, where fans and race teams come together each race week for the spectacle of race day.
Curving, sloped forms are evocative not only of the dynamic and changing sinuous shape of the racetrack but also of the perception of speed, which is at the heart of the NASCAR spectacle.
The expression of these forms could only have been achieved through the use of steel, as cladding and as structure, encompassing several long-span elements, architecturally exposed structural steel (AESS) elements, and employing innovative approaches to connections, steel detailing, and the interface of structural steel with stone, glass, and steel as a finish material.
The Hall of Fame consists of four basic elements:
• A large glazed oval shape forming a Great Hall serves as the symbolic core of the Hall of Fame.
• A rectangular volume houses visitor services, including entry and exhibit space on upper floors.
• An expressed Hall of Honor is situated as an iconic element within the Great Hall.
• A broadcast studio enlivens the Hall of Fame Plaza, the sweeping forecourt that welcomes visitors.
The results of the teams’ explorations of speed and spectacle evolved into an architectural element — the Ribbon – 5,000 stainless steel panels that envelope the full-block building in a form that speaks to the imagery and spirit of NASCAR. Made of stainless steel in a lustrous angel-hair finish that softly reflects light and accentuates its dynamic aspect, the Ribbon is a sculpted form that changes as it wraps around the building.
Within the Great Hall, a signature element of a curved banked ramp leads the visitor from the main floor to exhibit levels above. The ramp contains a display of race cars frozen in a moment from a race, capturing in another way the speed and spectacle that is the essence of the sport.
Steel trusses are used to achieve significant spans in the project: • A set of trusses spanning 175 feet achieve a grand column-free ballroom • A 100-foot-long, bi-level footbridge, supported by a pair of one-story-deep trusses, links the ballroom with the existing Charlotte
Convention Center. • Two- and three-story-high trusses cantilever 30 feet over the broadcast studio.
Among the AESS elements in the project is the Vierendeel frame supporting the glass façade of the Great Hall. The lateral-load-resisting system at this façade also functions as the braced frame that supports the Ribbon.
The project’s structural bid set was issued six months before the 100% CD set. The steel tender was divided into multiple packages to enable steel detailing and fabrication of portions of the project to proceed before the full design was complete. A 3D model was used in the steel detailing to identify and resolve potential conflicts in the field. These efforts and effective team communication allowed the long scheduled public opening to occur on time.
Owner/Developer: Forest City Ratner Companies, Brooklyn, N.Y.
Architect: AECOM, Kansas City, Mo.
Architect: SHoP Architects, New York, N.Y.
Structural Engineer: Thornton Tomasetti, New York
General Contractor: Hunt-Bovis joint venture, Indianapolis
Steel Fabricator: Banker Steel Company, Lynchburg, Va.
Steel Detailer: WSP Mountain Enterprises, Inc., Sharpsburg, Md.
Photographer: Bess Adler
The Barclays Center arena is the 675,000-sf home to the NBA’s Brooklyn Nets. The design-build project features 18,103 seats, an 85-foot open canopy that spans the entrance, and an ice floor for hockey and other events. The arena will host more than 200 sporting and cultural events annually with seating capacity increases to 19,000 for concerts and family shows. It features 95 luxury suites, four party suites, two conference suites, four bars/lounges, four clubs, a restaurant and several street-level retail stores. The project was designed to achieve LEED Silver certification.
The iconic feature of the of the arena is the weathered Cor-ten steel lattice that wraps around the structure. Rows of steel panels envelop the exterior including an entrance canopy that cantilevers 85 feet over the plaza. The façade design with 12,000 pre-weathered steel panels and the canopy were added a month after the GMP package was released and two months before the first steel mill order was due. This required the team to incorporate the developing façade design while keeping pace with the original schedule. Nearly 1,000 tons of steel was added to support the façade, which also became a prominent design feature.
The distinctive arched roof spans more than 380 ft and is supported by a pair of 350-ft tied arch trusses spanning the long direction of the arena. The roof system geometry is complex, further complicated by the additional loads imposed by the outer façade system. The building lateral system and diaphragms were designed to resist thrust forces from the roof arches, which were minimized by use of the tension tie.
The arena’s location in a tight urban setting near a subway station and train terminal presented a multitude of challenges for the foundation system. To facilitate truck turnaround, a pair of truck elevators were designed to feed a below-grade loading dock with a large truck turntable. Building columns in this area were transferred using large plate girders spanning over the dock.
The project’s structural engineer provide structural models, connection samples, and full connection design, which allowed the team to produce models quickly, store large quantities of information and coordinate with the entire team. From its initial design, the project constantly pushed the limits of building information modeling (BIM). The complex geometry of the façade and the shortened schedule meant that the team needed to coordinate in a 3D environment and provide the information to the contractor in this format as well.
The schedule was adjusted frequently and changed even from hour to hour at the peak of construction. The design team consisted of staff members across multiple offices and practice areas. Managing the team’s efforts on such a large, fast moving project made coordination critical to the project’s success. Teams in Kansas City and New York designed the roof and bowl after which the two components were integrated. Construction support services teams worked on the structural models, model delivery and connection design. Erection engineering was performed in Chicago. Achieving integration of these services in a way that is seamless to the client required extensive communication, intense collaboration and careful management. Design staff was maintained on site full-time to accommodate changes and oversee work. Weekly coordination meetings helped identify issues early on and develop solutions proactively.
Owner/Developer: National Geospatial-Intelligence Agency, Springfield, Va.
Owner’s Representative: U.S. Army Corps of Engineers-Baltimore District, Fort Belvoir, Va.
Architect: RTKL/KlingStubbins joint venture, Baltimore
Structural Engineer: RTKL/ KlingStubbins joint venture, Baltimore
General Contractor: Clark/Balfour Beatty joint venture, Bethesda, Md.
Steel Fabricator: SteelFab Inc., Charlotte, N.C.
Steel Detailer: SteelFab Inc., Charlotte, N.C.
Consultant: Hinman Consulting Engineers, San Francisco
Photo: Paul Warchol
Situated on the outskirts of the Capital Beltway adjacent to the Accotink Creek stands the National Geospatial-Intelligence Agency’s (NGA) 2.4 million-sf campus known as New Campus East (NCE), which has not only been designed to enhance the agency’s capabilities as one of the leading intelligence organizations in the world but also to achieve a unifying, cultural transformation. This effort to foster a unified culture is expressed in the design of the nine-story Main Office Building.
Composed of two curved 900-foot long overlapping bars around a 500-foot long central atrium and elliptical auditorium, the building’s overall form is in the shape of a lens — a fitting metaphor for NGA which serves as the nation’s eyes as the primary source of geospatial intelligence (GEOINT) for the purposes of U.S. national security, defense and disaster relief.
This defining architectural expression was accomplished primarily due to the benefits of structural steel. Steel facilitated the large bay size needed for program flexibility of the typical office, reinforced the architectural concept and imagery expressed in the transparent atrium roof, west end wall and exterior V columns, and accommodated the constraints of highly complex technical anti-terrorism/force protection (ATFP) criteria and a demanding schedule.
Managed by the U.S. Army Corps of Engineers (USACE) Baltimore District, the project has its origins in the 2005 Base Realignment and Closure Act (BRAC). RTKL Associates Inc. and KlingStubbins formed a joint venture to provide design services, including master planning and full architecture, engineering, interiors, site/civil, landscape and technology design.
At 2.2 million sf, the nine-story Main Office Building is the second largest single occupancy building in the world (after the Pentagon) and the largest federal building in the world to achieve LEED Gold certification from the U.S. Green Building Council (USGBC).
To fill the central atrium and interior of the building with light, the west end wall of the atrium was glazed with a curtain-wall system and the roof of the atrium was covered with a transparent fabric membrane. The west end atrium wall consists of a 135 foot tall by 140 foot wide curtain wall backed by a round hollow structural section (HSS) tube steel frame. Architecturally exposed structural steel (AESS) requirements were incorporated into the design, fabrication and erection of the space frame structure which served several functions. In addition to supporting the gravity loads of the curtain-wall, it supports atrium roof gravity and wind loads, and meets all mandated ATFP criteria. It also acts as a pedestrian bridge at several levels providing access and circulation between the towers.
The central atrium also serves as the main area of pedestrian circulation with a central elevator core linked by multiple bridges to each tower. Structural steel minimized the visual obstruction of these elements within the atrium and enabled them to be constructed after the towers.
The atrium roof is over 500 feet long and 45,000 sf, and consists of AESS arched steel tube members supporting an air-filled ethylene tetrafluoroethylene (ETFE) fabric roof. Although it appears clear, the custom silkscreen pattern and air filled ETFE system provides significant daylight while minimizing solar gain. Being extremely lightweight minimized ATFP-related effects, and aided in reducing the tube structure size and tonnage.
The two 900 foot wings are configured to focus on the central atrium. These dramatic spaces, as well as, the atrium’s light filled amenities create a main street for the office building community. The west end atrium wall and the atrium roof structure enhance this effect.
The unique exterior design of the main office building was achieved using signature “V” columns spaced at 40 foot on center and featured along the first and second floor perimeter, providing a separation between the visually solid base and the triangulated precast façade of the upper six floors, while also continuing the diagonals of the upper façade. In addition to providing a strong aesthetic statement, the “V” columns participate in the lateral load resisting system and accommodate alternate load path/progressive collapse design.
As with every project, the main office building had its complexities with the most obvious being its size. Using innovative Early Contractor Involvement (ECI), the USACE Baltimore District awarded the construction contract early in the design process, at about 35% design, enabling the contractor to provide valuable input to the design process and facilitate fast-tracking and value engineering. In addition, the design team delivered phased procurement packages including steel mill-order and fabrication. A committed long-term partnering process between owner, designer and contractor began early in the design process, built trust and fostered a one-team environment. That collaborative effort fostered flexible and creative, attitudes by all parties, and was a key factor leading to the project being completed on budget and six months ahead of original schedule.
Owner: City Creek Reserve, Salt Lake City
Architect: Hobbs + Black Architects, Ann Arbor, Mich.
Structural Engineer: Magnusson Klemencic Associates, Seattle
General Contractor: Jacobsen Construction, Salt Lake City
Steel Fabricator: Ducworks, Inc., Logan, Utah
Steel Detailer: Uni-Systems, Minneapolis
Steel Erector: Uni-Systems, Minneapolis
Mechanization Consultant: Uni-Systems, Minneapolis
Photograph: Magnusson Klemencic Associates
City Creek Center is the result of a plan by the Church of Jesus Christ of Latter‐day Saints to transform two Salt Lake City mega‐blocks just south of Temple Square into a 5.5 million-sf, mixed‐use development featuring retail, residential, office, and parking space. Developers wanted an urban, open‐air setting, but also needed the assurance that retail businesses would be protected during inclement weather. After studying many skylight possibilities, the project’s structural engineer produced a retractable roof concept that fully met the developer’s needs.
The resulting retractable, barrel‐vaulted roof is configured in two sections, each spanning one city block. Each section is 240 ft. long and 58 ft wide, with an S‐shape that echoes the curve of the signature City Creek. The precision‐sculpted steel and glass transparently shields patrons when closed, and disappears from sight when open; connecting nature with the areas below.
For each block, the retractable roof is comprised of three pairs of glass‐covered, arching panels that cantilever 33 ft from the adjacent structures over the retail concourse. When closed, all six panels seal together and create an air and water‐tight barrier. To open, the panels part in the middle and retract onto the building structure as the panels bow down out of sight from below.
Key to the bowing action are innovative whalebone‐shaped ribs that support the glass roof. Each roof panel is comprised of three parallel whalebones made of curved and tapered welded steel box girders that run from the tip of each panel’s arch to the end of its back span.
The glazed portion of the three whalebone arches are joined by four purlins made of 8‐in. XX‐strong A106 Grade B pipe and one purlin of hollow structural section (HSS) 10‐3/4 x 1⁄2 in. ASTM A500 Grade B tube. The purlins are designed with concealed connections that are invisible from below. The three whalebone back spans are connected with rectangular HSS ASTM A500 Grade B tubing in a K‐brace configuration to provide shear stiffness between whalebones. In order to meet special finish and detailing requirements, the side and bottom whalebone girder walls were ground and filled to produce perfectly flat plane surfaces.
The whalebones were built in two sections using custom‐ designed fixtures and joined with a plate‐welded connection to accommodate the unique geometry. The preassembled rail girders and whalebones were hoisted onto the roof, and the panels were assembled in place, stick framing whalebones, purlins, and K‐braces.
Each 10.5‐ton whalebone is supported by a 27‐in. double‐flanged steel wheel located at the bottom of the arch and two guide rollers located at the end of the back span. The wheel follows one geometric path on top of the rail girder, and the guide rollers ride an inclined track along the bottom of the rail girder. As the guide rollers travel up the incline, the roof’s cantilevered front edge dips down, causing the roof to bow down, with the wheel as the vertical rotation point.
An industrial computer located in a remote control room operates the retractable roof, which travels up to 8 ft per minute and opens or closes in approximately 6 minutes. Each panel has a unique operating sequence to prevent the panels from interfering with one another as the seals engage and disengage. The roof’s curvature, along with its complex seals and intersecting panels, made the control system the most complicated ever developed by the mechanization engineer.
Owner: 23 High Line, LLC, New York
Architect: Neil M. Denari Architects, Los Angeles
Structural Engineer: DeSimone Consulting Engineers, New York
General Contractor: TF Nickel & Associates, Ronkonkoma, N.Y.
Photograph: Rinze van Brug Photography
Located in Manhattan’s West Chelsea District, HL23 creates a new 14-story, 42,395-sf ultra-luxury residential building. In total, the project creates 11 condominium units, 3,585 sf of ground floor gallery space and an elevated terrace/garden area. The floor plate of the building, which is smaller at the base than at the top, owes its uniqueness to the existing elevated exposed Highline Railway – retrofitted into a city park facility – located at the eastern portion of the building lot.
Clad with a mega-panel glass and stainless steel curtain wall system, the project’s distinct form comes from the dramatic sloping of the south and east facades, creating a dynamic and undulating three-dimensional composition.
The building’s dual-lateral support system is the most intriguing element of the structure. A steel plate shear wall (SPSW) system – unique in New York City — provided the project with the benefits of increased stiffness and smaller dimension – both tremendous benefits for this site. The SPSW system is located at the elevator and stairs in combination with a full-building perimeter braced frame system. As a true sign of synergy between form and function, the architect incorporated the perimeter lateral pipe braces into the final interior aesthetic of the residences. This required special care during the design of the exposed connections of the perimeter steel diagonal braces to perimeter steel beams. It was achieved by replacing the traditional use of multiple bolts gusset plates with end plates hidden in the concrete metal deck slab for intermediate diagonal braces and with pin-end connections for end braces.
Architectural requirements played a large part in the final structural layout, and the use of structural steel was driven by three primary factors: • Minimizing the overall weight of the structure for the capacity of the raft foundation • Minimizing the amount of interior columns • Providing the perimeter diagonal architectural expression.
In New York, most residential buildings are designed using a cast-in-place reinforced concrete flat plate system to maximize floor-to-floor height. However, due to the unique geometry of the building, the sprawling architectural layouts, the quality of the soil, and the hybrid gravity and lateral load system on the perimeter of the building, steel was the more economical and efficient material of choice.
Floor beams are composite with the concrete slab-on-deck; however, all of the intermediate steel beams were removed to increase headroom in the living areas. This was achieved by using shored construction in many areas with a slab thickness between 6 in. and 7 in. and varying metal deck properties throughout the floor. At the upper floors, the maximum beam/girder span was nearly 30’-0”.
Due to the building’s modest height, a SPSW system was considered both-structurally effective and visually attractive. The east-west dimension of the building is very tight, and any reduction in dimension of structure was beneficial to the floor layouts. Using 3/8-in. thick plates, instead of wide-flange brace members, freed up an extra foot of usable floor area between the columns for each wall of the system. This two foot savings was an enormous achievement in a building that is 38 feet wide.
To help speed erection, the structural engineer worked with the general contractor and the fabricator to develop a system where the perimeter of the plate was continuously welded, with three of the four sides shop welded. Prefabricated shear wall panels, with integral columns and beams, were shipped to the site and spliced in the field. This process ultimately saved a considerable amount of time in erecting the SPSW system.
The second part of the dual lateral system is comprised of perimeter brace frames on each of the elevations. In addition to lateral loads, the perimeter braced frames in many locations are part of the gravity system as well. The braced exoskeleton members are 8” diameter double-extra strong pipes at the North, South and part of the East façade; HSS 10×5 tubes on the West facade and 6×4 back-to-back angles on the remainder of the East facade. All of the pipe elements are primary architectural features and exposed on the façade and in the residences. Therefore, the detailing of these elements was heavily scrutinized. In addition to standard Architecturally Exposed Structural Steel (AESS) specifications, the nodes of the system have been designed with an exposed single 11⁄2-in. diameter pin connection. The final building aesthetic merges the strength and beauty of steel into a composite whole.
See the remaining 8 choices in the full article RIGHT HERE!