A Fabrication Feat
Representing the five books of the Torah, the undulating glass façade of the Lincoln Square Synagogue in New York City features five horizontal ribbons of faceted glass panels with pleated fabric laminated in the exterior lite to give the appearance of paper parchment rolls. Skylights and soffit panels bridge the space between the ribbons. To illuminate the glass ribbons in the evening, two LED fixtures light the IGUs from the top and bottom. The LEDs are wired through the curtain-wall system and controlled via the centralized Building Management System. The low-angle illumination strikes the silk screen pattern on the interior laminated lite with a graduated intensity, making the glass appear to glow at night. Photo by Cameron R. Neilsen.
Each of the vertical, double-laminated, insulating glass units incorporates low-iron glass in its construction. The IGU is composed of: an exterior laminated lite of 4 mm heatstrengthened glass + 1.54 mm SentryGlas interlayer + the fabric + 1.54 mm SentryGlas interlayer + 4 mm heat-strengthened glass; a 12 mm airspace; and an interior laminated lite of 6 mm heat-strengthened glass with a low-E coating on the No. 6 surface + 1.90 mm PVB interlayer + 6 mm heat-strengthened glass with a frit on the No. 8 surface.
Owner: Lincoln Square Synagogue, New York City
Representing the five books of the Torah, the undulating glass façade of the Lincoln Square Synagogue in New York City features five ribbons of faceted glass panels with pleated fabric laminated in the exterior lite to give the appearance of parchment scrolls. From the glass design, to the fabrication, to the installation, this unique facade presented engineering challenges to all involved, bringing together a team of glass and metal fabricators from around the world in its creation.
Front Inc., www.frontinc.com, in collaboration with architecture firm CetraRuddy, www.cetraruddy.com, designed and engineered this distinct façade, relying on companies from China, Mexico, France, Canada and the United States to make its vision a reality (see “The Players” on Page 45).
The finished façade features five horizontal ribbons of double-laminated, insulating glass panels. Each of the 250 vertical IGUs is 400 millimeters wide and varies in height from 2,470 mm (8 feet, 1 ¼ inch) to 4,912 mm (16 feet, 1 3/8 inch). A pleated, sheer fabric laminated in the panels’ exterior lite works together with a custom, white ceramic silk-screen dot pattern on the interior lite to provide privacy for synagogue worshippers. Manufactured in France by Creations Methaphores, the Hermes open-weave fabric is made of 100 percent trevira, a non-organic material typically used for vessel sails. To illuminate the glass ribbons in the evening, two LED fixtures light the IGUs from the top and bottom.
“This glazing configuration created fabrication challenges,” explains Adrian Betanzos, façade consultant for Front. Because the pleated fabric created an uneven surface for lamination, Front designers decided to encapsulate it between two Dupont SentryGlas interlayers. The façade consulting firm chose SentryGlas due to the interlayer’s structural and delamination performance, as well as its capacity to flow more readily when heated, allowing it to permeate all layers of the fabric and its pleats, Betanzos says.
“At the time of the facade design, the lamination of a textile had never been done for an exterior application where the glass is exposed to the elements and has to resist all of the design loads,” Betanzos says. “Because of that, we performed extensive testing to assure the client—and ourselves—that this was a possibility.”
Samples were produced and tested at Bodycote Materials Testing in Toronto and at Architectural Testing Inc. in York, Pa., www.archtest.com, before the final units were fabricated in China by AVIC Sanxin Glass Technologies. Testing included thermal cycling for heat and humidity, boil test, bake test, accelerated UV test, structural integrity testing and energy/daylight testing per National Fenestration Rating Council requirements.
A Front representative oversaw final glass fabrication in China to ensure it met exacting standards, according to Betanzos. The fabrication took a total of four months, from February 2010 to May 2010; however, a construction delay of 12 months at the synagogue site meant the glass had to sit at the AVIC facilities for an extended period of time. Concerned that weather conditions in Southern China might create mildew and/or condensation marks on the exterior surfaces of the glass, Front opened all of the crates to visually inspect each glass unit before shipping them to New York.
Designed as a stick system glazed onsite, the synagogue’s curtain wall has more than 2,500 unique components, with only the vertical mullions and glass repeating. Here, glaziers install more than 60 sets of shadow boxes.
The prep work
Prior to installing the façade, Front commissioned Theometrics Inc., www.theometrics.com, to survey the existing steel structure and concrete elements that interfaced with the façade, and create a 3D model of the building in CAD. Theometrics then translated the information to Front’s BIM model, allowing the firm to verify the façade system would fit by comparing the 3D “as-built” model with the design model used for fabrication. Front repeated the process for each of the top and bottom brackets that were to receive the curtainwall panels. By doing so, the firm was able to “design alternative solutions prior to site mobilization of the installation crew, saving valuable time and money for us and the client,” Betanzos says.
After Front experts checked the “asbuilt” model, contract glazier Walsh Glass and Metal, Yonkers, N.Y., began the façade installation. Designed as a stick system glazed onsite, the curtain wall has more than 2,500 unique components, with only the vertical mullions and glass repeating. Installation took place in two phases. First, glaziers installed the secondary architectural exposed structural steel for the first two floors of the synagogue, where the sanctuary is located. Consisting of 10 columns and 20 CNC-rolled HSS steel members, the AESS supports all of the top connections for the first, second and third-floor glass ribbons.
The second phase included the installation of the secondary steel, bottom brackets, aluminum stick system and more than 60 sets of shadow boxes. The bottom transoms and shadow boxes were assembled in sets of four pieces onto a laser-cut and drilled sill plate that accurately set the geometry of each façade element. The shadow boxes were attached with steel T brackets to the structure.
“The set out was the most important step of the construction,” Betanzos says. “Once this was complete, all the consequent aluminum elements followed their correct position on the building.”
To provide glaziers access to all points of the undulating façade during glass installation, Greg Beeche, Logistics created custom rigging equipment that incorporated a 16-foot long, twotier work platform.
The platform consisted of four, 4-foot square bays. At the two middle bays, independent 9-footlong decks were mounted on aluminum rollers, allowing workers to adjust their working location on demand, traversing in and out, up to five feet perpendicular to the facade.
The glass installation
The façade’s undulating design presented the Walsh Glass and Metal team with a significant challenge when it came to installing the glass panels. “We needed a system capable of reaching all of the points from the outside of the building," Betanzos says. “In some locations, we had a floor overlap of more than 5 feet.”
Front asked Greg Beeche, Logistics, www.gregbeeche.com, to provide rigging equipment that would enable the Walsh team to install the IGUs. After two months of design work and another month of fabrication, GBL delivered a workaccess system that featured a 70-footlong, 3-foot-deep, double-truss rooftrack system that supported a track-riding roof carriage, from which a dynamic 16-foot-long, two-tier work platform was suspended to provide direct access for workers installing the glass panels.
The track-riding roof carriage accessed the full length of the wall and allowed workers on the platform to install the glass panels, while others used the roof carriage to hoist panels into an accessible area on the platform. However, the work platform itself was the centerpiece of the system. Its two floors allowed a worker at the top floor and a worker at the bottom floor to maneuver and install curtain-wall panels as a team, according to Betanzos.
Teamwork was critical not only to the installation of the glass panels, but to the entire façade project. “[We were able to] utilize worldwide work relationships fostered over many years,” Betanzos says. “Parts were designed and fabricated on three different continents, with the assistance of many man hours. The successful completion of the façade could not have been [accomplished] without the collaboration of all of the key players."