Posts tagged with "Exoskeletons":

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Limestone load-bearing exoskeleton spawns outrage in London

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In a time when stone is primarily used in facades as screen walls or purely decorative cladding, London’s 15 Clerkenwell Close by Groupwork + Amin Taha Architects (ATA) brings structure to the fore with a load-bearing masonry exoskeleton. Since construction in November 2017, the mixed-use development, which is the home of Taha and his practice, has proved contentious between critics and local authorities. While the firm was awarded the 2017 RIBA Award, the Islington Council has ordered the architect to demolish the structure for a perceived incongruity with the surrounding historical context—albeit a significant portion of Islington's architectural stock was built in the mid-20th century with half brick facades—a major complaint being the rustic quality of the limestone slabs.
  • Facade Manufacturer & Installer Stonemasonry Company Ltd, Ace Sheet Metal Ltd, Glasstec Ltd
  • Architects Groupwork + Amin Taha Architects
  • Facade Consultants Webb Yates Engineers Ltd
  • Location London, United Kingdom
  • Date of Completion November 2017
  • System Concrete floor slabs fastened to load-bearing masonry with unitized glass-and-wood curtain wall
  • Products Limestone blocks, double glazing bonded through nylon thermal isolators to bronze finished metal curtain wall system
To source the limestone facade, ATA went across the English Channel to a quarry outside of Lyons-la-Forêt in Northern France. According to Project Architect Dominic Kacinskas, "the region is noted for its continued use of strength certificates with a generations-old workforce well trained in extracting stone and splitting it accordingly." In contrast to historic and contemporary stone construction that is polished, chiseled, or hammered into a relatively smooth surface, the project’s columns and lintels are left in their semi-unfinished state. Striped indentations formed from the splitting process and fossilized remains track across the facade along with the smooth faces of bedding planes. Columns and lintels, all roughly measuring 10 feet by 1.5 feet by 1.5 feet, are stacked atop each other in a six-story square grid. Each block is bonded to the next with just under an inch of mortar and gravitational force. In total, the limestone exoskeleton weighs just under 250 tons. The reinforced concrete floor slabs, measuring nearly eight inches thick, are embedded with a series of steel plate casts that are bolted to external metal bosses through thermal isolator nylon plates. The metal bosses are in turn grouted into a system of galvanized steel I-beams placed at the meeting point of horizontal and vertical stone elements. Groupwork + Amin Taha Architects were able to execute a continuous bespoke curtain wall inches behind the load-bearing masonry effectively disengaged from the structure through the use of pinpointed metal fastenings. Window openings, composed of double-glazed units with metal brass finished frames, follow the equal subdivision of the exterior's stone structural grid. The design team placed solid oak timber panels where outward views are not permitted by the columns, which are grafted atop a solid oak sub-frame. Along the side elevations of 15 Clerkenwell Close, the design team elected to keep intact the original red brick party walls abutting adjacent structures. This decision is most apparent on the northwest elevation where a new grid of limestone, and infill grey brick, is cut into the party wall to support the insertion of new floor and roof slabs. Why the controversy? The Islington Council contends that Groupwork + Amin Taha Architects did not accurately display the finish of each stone component of the facade. According to the firm, the rough finish of the limestone, formed by millions of years of fossilized marine organisms, quartz pockets, and other sedimentary products, "is only discoverable weeks before installation on site as the stonemasons sub-divide the extracted stone into sizes set by the structural engineer." An appeal against the motion of demolition will occur in April 2019.
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Tree-like diagrid columns connect two greenspaces in Manhattan’s Upper West Side

Unbroken bands of window walls sit beyond an exterior concrete structural frame.

Completed earlier this year, a new market rate rental building on Manhattan’s Upper West Side by Handel Architects features a striking exposed cast-in-place concrete diagrid “exoskeleton” structure. The system is designed in response to required zoning code setbacks that restrict building area to a mere 35’ wide at times. The project, named after it’s address at 170 Amsterdam, is located two blocks north of Lincoln Center, situated between two greenspaces – Central Park and the Lincoln Tower superblock – via 68th Street. The lobby is a prominent glassy space containing a mix of community programs, formally and programmatically connecting the two sides of the building together, while abstracted tree-like columns punctuate the building envelope. Frank Fusaro, Partner at Handel Architects, says the use of exposed architectural concrete is a contextual response to its location between the muscular buildings of Lower Amsterdam, where Lincoln Center resides, and the heaviness of classic Upper West Side apartment buildings. “LaGuardia High Schools exposed concrete, MLK School’s corten metal and glass skin wrapped around an opaque core, and the heavily ornate Beaux-Arts exterior of the Dorilton with its quoining, ironwork, brackets, cartouches, oriels and other details all share something in common: these are tough, robust and bold buildings.”
  • Facade Manufacturer Residential Windows, Skyline Dual Action Windows; Retail storefront, YKK; Lobby entrance storefront: Sentech Architectural Systems; Metal Panel North and South walls, Painted Aluminum Composite Panel by Omega Panel Products; Ground floor (East), Canopy and Bulkhead: Pre-finished Cement Board: Fibre C; Wood cladding: Descience Laboratories; Wood trellis: Structurlam
  • Architects Handel Architects
  • Facade Installer Cast in Place Concrete, Ryder Construction/ RC Structures; Residential Windows, Skyline; Retail storefront & Lobby Entrance, Ground floor (East), Canopy and Bulkhead: Crowne Architectural Systems, Inc.; Metal Panel North and South walls, KNS Building Restoration Inc.; Wood cladding & trellis: JM3 Construction LLC)
  • Facade Consultants IBA Consulting & Engineering
  • Location New York, NY
  • Date of Completion April, 2015
  • System High strength exposed architectural cast in place concrete exoskeleton with continuous window wall
  • Products Concrete formwork, Molded Fiber Glass Construction Products; Glass: Insulated energy efficient glazing PPG Solarban 72 Starphire Operable window hardware, Geze
Aside from the contextual benefits to exposing a concrete system, the architects noted several benefits to a structural exoskeleton system, contributing to the client’s full support from nearly the beginning of the project. The most significant benefits to the building envelope design were seen when interior floor area was able to be maximized. The structural system of the building resembles a shell structure, achieving high stiffness from an exterior diagrid of columns tied together with repetitive structural floor slabs. This stiffness allows for no shear walls to be required in the core of the building and relatively few interior columns. By moving the columns to the outside of the building, the city’s zoning department allowed for the floor area of the building to be measured to the face of the window wall, rather than the face of the structure. This allowed the architects to add an entire extra floor of program to the building. Additionally, the depth of the facade assembly acts as a brise soleil, passively helping to manage a less-than-ideal solar orientation (unavoidable due to the city grid and buildable area on site). Beyond the columns, a continuous band of window units, spanning from floor to ceiling, establishes the building’s thermal envelope. The windows feature a high performance low e coating to allow for high levels of transparency without sacrificing solar performance. Fusaro says the unbroken line of windows in the apartment units was essential: “The studios are sized just over 400 square feet, so having an exterior wall of glass makes the units feel much larger.” An extremely dense mix of concrete allows for the smooth finish and eliminates voids. The use of less rebar permits a pump tube to be placed in the column and minimizes vibration. Slag was added to the mix to make the color of the concrete more like limestone. Installation of the building envelope after the concrete was poured occurred surprisingly quickly, at a rate of about one floor per week, adding value to the system. The design of the diagrid was optimized to reduce the quantity of fabricating costly “X” forms by shifting the grid on a diagonal axis. The success of 170 Amsterdam has led Handel Architects to further work with exposed architectural cast in place concrete. Most notably, in the Upper West Side, another market rate rental building is under construction currently. For Fusaro, the elegance of exposed concrete is activated with an underlying connection to nature: “I love the organic nature of concrete, you can add or subtract a little of this or that and make it into something entirely different.” Handel Architects: Partner in Charge/Design Principal; Frank Fusaro Project Manager; Honyi Wang Design Team; Alan Noah-Navarro, Elga Killinger, Shridhuli Solanki, Rinaldo Perez, Ren Zhong Huang, Jessica Kuo, Jordan Young, Shujian Jian, Hong Min Kim, Ade Herkarisma, Ana Untiveros-Ferrel
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The Grand Macau Hotel: Zaha Hadid Behind Parametric Addition to Chinese Casino Resort

Zaha Hadid has designed another seemingly-structurally-impossible parametric building form that is set to touch down in Macau in 2017. The building, which could be equally at home in Miami or Dubai, is a large block that has been punctured by three curvaceous openings. The entire mass is encased in an exposed exoskeleton that twists and turns along the structure's contours. The project was undertaken at the behest of Melco Crown Entertainment, casino magnates who have contributed the City of Dreams resort to the gambling-soaked Chinese island. The developers commissioned Hadid to create the fifth hotel located on the property, which will top out at 40 stories and house 780 rooms in over 1.6 million square feet of space. Other expected amenities include luxury retail, specialty restaurants, spa facilities, a roof-top pool, and a number of gaming areas. The external latticework varies in patterning as it crawls up the structure's facade. It is densest at its middle, where it navigates the irregularities of the design's central void, and becomes more elongated at each of the building's poles. The interior is more angular, awash in crystalline glass outcroppings subdivided by triangular grids. These walls collide with the curved base of the structure's opening to create a 130-foot central atrium that welcomes arriving visitors to the hotel. Construction for the newest member of the City of Dreams is already underway.