Düsseldorf’s  
Kö-Bogen Shows  
Curved Glass  
the Bend bPy oNicsksSti. bDeinlisities  
Around  
Glass is only as flat as the façade wants it to be.  
That seemed to be the approach to the Kö-Bogen,  
or the “King’s Bow,” mixed-use commercial complex  
in the heart of Düsseldorf, Germany. The large-scale  
office and retail complex connects the city’s central  
park and historic commercial center and consists of  
two 85-foot-high buildings and a connecting bridge.  
Designed by New York architect Daniel Libeskind,  
the buildings sport large façades of natural stone and  
curved glass elements.  
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Architects’ Guide to Glass & Metal  
The total façade area spans more than  
160,000 square feet, with more than 86,000  
square feet of flat insulating glass and another  
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3,000-plus square feet of curved and bent  
glass produced by Saint-Gobain Glassolutions  
Objektcenter Döring Berlin. These elements  
measured up to 8.6 feet by 18.4 feet in different  
radii, some bent more sharply than others. The  
project also includes 24 different geometric  
buckled” shapes.  
Challenges posed by the complicated design  
carried over from the pre-construction phase to  
the installation. Proper scheduling was critical.  
Because the project featured so many unique  
façade elements, logistics were very important  
during the installation, and Lindner had to  
make sure that the correct element was onsite at  
the right time.  
Lindner designed the façade system  
and compiled technical drawings for  
the project, as well as both static and  
building physics testing. According to  
the company, the method of fixation for  
the lites wasn’t regulated in Germany,  
so the firm “performed countless calcu-  
lations and thorough testing to get the  
approval of the building authorities.”  
According to Christoph Rubel,  
European technical manager of  
Edgetech Europe, the softly curved  
shape of the building contains a variety  
of angles in the post-and-beam con-  
struction. “The challenge is to receive  
the widths both the same on the inside  
and the outside. [To do so] a special  
fulcrum had to be used, and the outer  
glass bar had to be made in different  
widths,” he says. “The glass façade is  
designed with a load-bearing bonding  
from both sides, so that the outer  
bonding was used as mechanical safety  
and thus could have been approved by  
the building authorities.”  
continued on page 30  
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29  
Aconrtionuuednfrdom tpahgee 29Bend  
Mock-up design of the geometric shape was done well  
in advance, as the bent-glass producer worked on technical  
solutions for the desired “kinks” in the glass.  
Insulating glass spacers used for the curved and  
bent insulating glass units had to accommodate a  
variety of different requirements, which provided a  
unique challenge for Edgetech Europe, a subsidiary  
of Quanex Building Products. Additionally, various  
tests were done that involved bending the glass with  
different coatings to the desired geometry.  
Rubel says the extent to which curved and ther-  
mally kinked double insulating glass was used on  
the project was unique. “Only through intensive  
collaboration between all parties involved and the  
expertise gained through many projects over the  
years, a real project like this with unique panel  
geometries could have been achieved,” he says.  
In addition, the consequent development and  
upgrading of equipment and process had made the  
thermal bending of the highly sensitive coatings in  
small radii possible.”  
2
0–23 September 2016  
Düsseldorf, Germany  
Inspired by glass  
Pure inspiration! glasstec, the world’s leading trade fair, presents  
solutions and products for energy-efficient building.  
The best way to prepare for your show visit is to use the sector  
guide on the glasstec portal, where you will find all the offers for  
your sector.  
For show information: Messe Düsseldorf North America  
1
50 North Michigan Avenue  
Suite 2920_Chicago, IL 60601  
Tel. (312)781-5180_Fax (312)781-5188  
info@mdna.com_www.mdna.com  
For hotel and travel arrangements: TTI Travel, Inc.  
Tel. (866)674-3476_Fax (212)674-3477  
www.glasstec.de/architectureconstruction  
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Architects’ Guide to Glass & Metal  
The façade is intricately patterned: horizontal from some vantage points,  
vertical from others, and conceived so that the arrangement of stone and glass  
panels and aluminum louvers express a homogenous reading,” according to  
information from façade contractor Lindner Group of Arnstorf, Germany.  
Murphy Façade Studio, based  
in Ireland, assisted the architect  
in the design phase. The design,  
as described by Murphy, “incor-  
porates the use of fully bespoke  
factory fabricated twin skin [unit-  
ized] panels with integrated vene-  
tian blinds in the upper three  
office floors of the building.” The  
lower three retail floors incorpo-  
rate large-format glazed unitized  
panels. “The [unitized] panels  
also contain flat and curved trav-  
ertine natural stone, including  
operable stone vents, from the  
Tivoli quarries outside Rome,”  
according to Murphy. AGG  
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