The double glass super spacer bar project case: The national library of Qatar
The National Library of Qatar includes the Doha National Library, the Public Library, and the University Library. At the same time, the library contains precious documents and manuscripts related to Arab and Islamic culture. By then, the public library will hold more than 100,000 books and provide more than 42,000 square meters of reading space for thousands of readers. The library is part of the Education City-in the Education City are the research institute branches of the world's top universities.
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1. Flexible spacer system suitable for the desert climate
The glass manufacturer CRICURSA has long used Super Spacer® to produce curved insulating glass with a large surface, which presents a unique and exquisite appearance. For energy-saving considerations, super spacers are also used as warm-edge products in the Qatar National Library project in Doha, which was built in 2018 and has a 5.5-meter-high glass curtain wall.
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2. The wave shape makes it more stable
Professor Rob Nijsse, a structural mechanics expert and former partner of the Dutch ABT Arnhem engineering company, and Ronald Wenting, a load-bearing consultant for ABT construction, participated as the structural design manager in the first project of the collaboration between Rem Koolhaas and CRICURS-Porto’s Casa da Música concert hall; in the past 15 years, the famous architect Rem Koolhaas and his architectural firm OMA Architekten in Rotterdam have been using the wave-shaped glass curtain wall as their trademark.
In the article "Designing and Constructing Waved Glass Facades" by Rob Njisse and Roland Wenting, they wrote: "If you can use a piece of paper to make the wave shape you want, then glass can do it now."
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The static advantage of the corrugated facade is obvious. The static folded paper essentially provides better rigidity than the flat plate, which also applies to the glass facade. However, this sentence is easy to say, but it is not so easy to do.
These two structural designers also realized from practice that there are only a handful of curved glass manufacturing companies in the world that can produce large-surface curved glass products that meet the quality requirements.
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In addition, to make the glass facade act as a load transmission and structural support component at the same time, the design team began a new exploration. For the Porto project, Rem Koolhaas hopes to build a glass facade without a steel structure, if possible at the same time, it is a huge challenge to abandon cumbersome columns, beams, steel cables, or frames. Thanks to CRICURSA, one of the most famous curved glass manufacturers in the world, this challenge was finally broken. The curved glass of the super large plate does not have a vertical frame and is arranged in a wave-like manner to support each other and share the load.
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3. Curved glass with the smallest radius of curvature
Similarly, in the building of the Qatar National Library in Doha Education City, Rem Koolhaas also chose a wavy glass facade.
The curved glass here is arranged in an Ω shape, inspired by images that look like dry paper. The glass façade is diamond-shaped, like the four corners of a box folded upwards. By filtering the sunlight, they use soft natural light to illuminate the library. The white aluminum cover reflects light into the room, and visitors can also discover different patterns produced by reflection or refraction. At the same time, the transparency produced by the glass facade will also give visitors a sense of open space.
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The entrance to the 138-meter-long library is not on the side but in the center of a triangular room under the supporting corner of the building. This room is surrounded by three terraces, which are filled with books. The National Library of Qatar covers an area of 500,000 square meters, has a collection of more than 1 million books, and about 42,000 electronic versions. On a suspension bridge that almost suspends the entire room, the middle floor is equipped with a reading room, a multimedia room, a study room, and a large auditorium. Those historical treasures, including texts and manuscripts of special value that record the Arab Islamic civilization, hope to be presented in the form of a permanent exhibition. OMA Architekten Rotterdam has found a rather unique solution: build a 6-meter deep room. Similar to an underground labyrinth, covered with beige travertine and hidden under a glass cover, the message expressed is quite clear: books are treasures worth cherishing.
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4. Facade with advantages of energy-saving and strength
The metal-free glass facade of the National Library of Qatar provides a key energy-saving advantage. The curved hollow glass made of warm edges and filled with argon gas minimizes thermal bridges and greatly reduces heat transfer. Enter the room. "Qatar is one of the regions most affected by the increase in average temperature caused by climate change," CRICURSA marketing director Joan Tarrus explained: "The outdoor temperature in summer exceeds 40 degrees, but the library must maintain a pleasant temperature of 20 degrees. Therefore, The energy-saving requirements and production technical challenges brought by the glass curtain wall are considerable, especially when we don’t want to insert any mechanical shading devices.”
Due to the self-supporting characteristics of curved glass, its facade has a very strong resistance to wind loads. “The same principle is also used by Antoni Gaudí in the famous catenary arch,” Joan Tarrus said.
Compared with a flat glass of the same thickness, wave-shaped glass allows greater vertical transmission of loads. According to Rob Nijsse and Roland Weining, the load-bearing capacity of the wave-shaped glass has increased by 1,000%. To make the building more stable, the metal brackets between the glass are connected to the internal pillars.
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Joan Tarrus added: “When we analyzed the structure of the curved double-glazed facade at OMA Architekten, bending under gravity seemed to be the only way forward for us. Although Doha’s extreme climatic conditions brought real technical challenges, curved float glass is the only way to achieve a unified solution in terms of geometry, coating, and size. The glass bending radius of 550 mm gives us more freedom in design."
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The 5.5-meter-high curved laminated glass is a double-layer hollow glass unit. The Low-E film layer and the shading layer filter and reflect sunlight. To further limit the transmission of heat radiation, a 3mm mesh is printed every 6mm on the glass. Grid, considering the very limited radius and considerable size, is technological innovation.
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5. Warm edges are essential in desert climates
For warm-edge spacers, CRICURSA chose the super spacer product TriSeal™ Flex. According to CRICURSA's research, the special products developed by Edgetech/Quantex for curved glass are ideal for extreme desert climates.
If you want to optimize buildings from an energy-saving perspective, Joachim Stoss, general manager of Edgetech Europe and vice president of international sales at Quanex, explained that in this climate area The use of warm edge technology is very important. From the heat of the day to the cold of the night, the temperature change will cause the glass to produce continuous breathing movement (pump effect), so the surrounding sealing system has to withstand considerable mechanical stress. "A flexible spacer system like a super spacer can maintain the long-term sealing durability of the hollow. Due to the characteristics of the elastic microporous structure, the spacer is always attached to the glass under the action of the pump effect to prevent seal failure", Joksim Stores Added.
In addition, Jinan LIJIANG Glass has integrated the upstream and downstream resources of insulating glass deep processing. Through understanding of nearly a thousand domestic suppliers who could produce the super spacer bar in China, it has selected high-quality insulating glass spacer suppliers in China as its partners. If you have relevant import some aluminum spacer bar or warm edge super spacer bar to produce the insulating glass, please contact us for more details.
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