Lakhta Center – a large scale project of the construction of a modern business area in the north-west of Saint Petersburg. Opening in 2018.
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Crystal Palaces or Why Skyscrapers Are Built of Glass?
"People preferring minerals to glass are very wrong, Shuvalov…" Mikhail Lomonosov wrote correctly in his time. Glass is one of the most ancient materials, it was known by builders of the ancient world already. Environmental performances, ability to let playful or solemn light, and even an enquiring gaze through, to disclose secrets of buildings’ structure and life of buildings’ occupants make glass the most popular construction material of modern times.
TRANSPERANCY EVOLUTION FROM THE INDUSTRIAL REVOLUTION TO THE PRESENT TIME
For the last two centuries glass acquired outstanding characteristics which made it one of the leading construction materials — environment-friendly and practically feasible at the same time. Production of cast sheet glass in 1848 was revolutionary as it allowed fabrication of huge sheets of tough glass at a low price. On an unprecedented scale they were used in the construction of the well-known Crystal Palace in London’s Hyde Park, which is a symbol of the Great Exhibition of 1851, and a whole gallery of similar facilities all over Europe.
For the first time in the world curtain-wall façade gained widespread use for permanent buildings in the Soviet Union. The first building with facade glazing – the Tsentrosoyuz Building was built in Moscow in 1936 by Le Corbusier.
In the middle of the ХХ century technologies allowed creation of large areas of perfectly flat glazing at height. In 1958 the Seagram Building was built in Manhattan. It gave rise to an international style of high-rise buildings in which functionality of interior structural elements was accentuated by transparency.
In 1995 artist Rick L. Silas offered innovative cold forming cast which added three-dimensionality to glass surfaces. According to his technology, flat multilayer glazed units are put into frames where they bend by gravity without any thermal treatment, and a created curvature ensures perfect smoothness of façade surface that can replicate any building form, even the most fanciful one. This can create unusual optical effects, for example, reflection of clouds as if rising diagonally.
This technology offered new opportunities for the international style in architecture: after Manhattan glass parallelepipeds, mankind started to use for living buildings with complicated asymmetrical surfaces – in a form of large spheres, Moebius bands, spirals, and fractals. Unique facade forms: convex, concave (for example, Confluence Natural History Museum in Lyon), twisted (such as the Evolution Tower in Moscow City) plentifully represented both in portfolios of Pritzker prize winners and applications of architecture competitions confirm that today glass is at a new peak of popularity as a construction and decorative material.
130 THOUSAND SQUARE METERS OF TECHNOLOGIES
The record breaker for having the largest facade glazing area is Lakhta Center Multifunctional Complex under construction in Saint Petersburg with the height of 462 meters. 85 per cent of the building surface is glazing consisting of 16 thousand of glazed units of various forms. Such volume of unique facade glass is used for a high-rise facility for the first time.
Modern glass facades are very environment-friendly, they enable maximum daylight illumination and since recently — natural ventilation which has not been previously used in high-rise buildings where ventilation windows and transom lights were not considered according to the safety rules.
In buffer zones of the facade there are ventilation windows creating natural draughts. In sunny days automatic louvres protect against heat. Thus, double façade cuts down consumption of energy for heating and air conditioning of premises. All technical tasks are regulated by a centralized intelligent control system without a need for human interference.
Glass buildings differ from their fellows by cleanliness as they require regular exterior cleaning. A specific cleaning system was developed for Lakhta Center — guides and hinge fasteners precisely follow the facade form turning in three planes; angular and straight platforms, and carriages will allow workers to clean both narrow and wide sides of Tower following the building geometry precisely. Above 369 meters, the facade will be cleaned by industrial climbers with the use of electric hoists.
A system of cranes and cradles for workers is considered for complex inclined parts of the façade. Movable cranes will be installed both on the roof and on the rail-guided platforms along the façade. Cleaning will be done twice a year: in spring and autumn.
STABILITY DESPITE VISUAL FRAGILITY
Skyscrapers in Hollywood blockbusters often collapse. However, despite screen images, real buildings are rather rugged structures able to bear a brunt of natural hazards or emergency situations. Developers and tenants realize their responsibility and possible losses; therefore prevention of negative factors is one of the priorities in the course of the modern buildings construction.
Façade safety is verified by special mock-up tests for fire resistance, durability, resistance to extreme weather conditions such as squally wind and rapid temperature changes. It is almost impossible to break, burn or break with voice state-of-the-art hardened glass. Thus, in Lakhta Center the outer glass is multilayer, heat-strengthened with thermal-reflecting coating. Internal glass is fully hardened. Glazed units are filled with argon. The double façade will ensure heat and noise insulation.
The building stands out against the surrounding air space due to illumination, which creates a silhouette for observers and scares birds during periods of their migration.
COURSE TO THE NORTH
Taking into account the climate of Russia, the control over icing of the façade requires unique solutions. For example, in Lakhta Center the spire is netlike by its structure. When the first harmless ice layer forms on such net, a short electric impulse shakes it and prevents the ice accretion. Nobody in the world used to fight against net icing; this technology is a unique solution.
Moreover, the Lakhta Center facade buffer zones mentioned already will not allow the external glass to be overcooled, and the internal glass will be completely ice-free. There is the special heating system that prevents icing of glass outside the buffer zones in case of severe frost.
PAST, PRESENT, AND FUTURE
Glass is one of the most eco-friendly and green materials of natural origin in the world; it is processed without losing its essential properties: transparency, thermal conductivity, aesthetic qualities, and ability to protect against environmental effects.
‘Glass is an example of how our standards are far behind new materials. In many countries this material is used not only as a decorative hookup element, but as а structural component— as a beam, for example, or a column that is a load bearing element ensuring reliability and safety of a facility during the operation of it. Glass will be used in architecture more and more wide,’ - believes Lakhta Center Chief Engineer Sergey Nikiforov.