Glass belongs to the materials, the use of which for the decoration of facades allowed to give them a special look, corresponding to the idea of an ideal modern building. This is facilitated by the aesthetic qualities of the glass surface, which can be mirrored, translucent, colored. The elegant look of frame structures, the ability to obtain clear edges and regular bends, large smooth surfaces also play a role. In general, the glazed building looks neat. In addition, the use of glass in facade decoration emphasizes the builders' possession of high (complex) technologies, which are the result of the progress of innovations. This requires a complex production of products with special operational and aesthetic qualities, ensuring high precision in the installation of structures. All this provides an image to those who can implement such a building, and to those who use it.
The attitude of professionals towards glass in architecture is not unambiguous. Some critics believe that a modern building with a glass facade can be appropriate in any architectural context, not overwhelming the historical environment, but reflecting and multiplying its masterpieces. Others raise the problem of the facelessness of the architecture of glass buildings, the loss of national features in it. Examples include the so-called. The "international" style introduced by Mies van der Rohe, in his construction of Lake Shore Drive, Seagram Building and many other UN buildings in New York, the Congress in Brazil, the Hydroproject Institute in Moscow, allow us to say that that "glass" architecture is universal and the same for any part of the world, as well as typical projects of large-panel houses.
In practice, the use of translucent facades does not always provide high quality architecture, glazing is not an absolute principle of obtaining a modern prestigious building, which is valid in all cases. Its application does not mean that the building will be successful. Glass is just a facade material, one of the architectural tools, the use of which should be appropriate in a particular case. To do this, it is necessary to satisfy a lot of requirements for the future building, which is provided by the design methodology. In accordance with it, as a rule, in the first place is the architectural and planning solution, developed taking into account the function of the building, to which the architectural and artistic solution based on the laws of composition, as well as the constructive solution, are subordinated.
Translucent facades used in the construction of modern buildings have a wide variety in terms of architectural aesthetic and technical characteristics. Their classification according to these characteristics makes it possible to create a system that facilitates the choice of the facade solution by the architect. For this, it is proposed to carry out a classification in two directions - an architectural and a constructive solution. In this case, the architectural solution will determine the choice of facade glazing in accordance with the architectural and planning and architectural and artistic requirements, and the constructive one - in accordance with the requirements for structures and their materials.
The classification of translucent facades according to the architectural design allows us to distinguish the following groups: perforated, tape, solid, ventilated with glass cladding, double.
Facades with perforated glazing (Fig. 1) are used in the architectural design of a building, when frames are installed between the supporting elements of its frame (protruding ends of floors, beams, columns, ends of walls). It turns out a facade on which the glazed planes are divided horizontally and vertically. In this case, the structures of the facade system are based on ceilings, and are also attached to the sides to walls or columns, and from above to the ceiling.
Facades with strip glazing (Fig. 2) are created by continuous horizontal openings without walls. As a result, floor strips are formed along one facade or the entire perimeter of the building, consisting of a continuous glazed strip and a continuous opaque window sill part of the wall. Bearing columns and walls in this case are made recessed behind the glazing tape. In this case, the structures of the facade system are based on ceilings or a window sill wall, are attached to the ceiling from above, and can also be attached to the ends of walls and columns.
The solid-glazed facades (Fig. 3) represent a horizontal and vertical continuous outer glass envelope. From the inside, glazing is carried out from floor to ceiling, from wall to wall. The structures of such a facade are attached by hanging them to the ends (leading edges) of the interfloor floors using cantilever brackets.
Ventilated facades with glass cladding provide the impression of a continuous glazing of the façade, while rooms have conventional windows. They provide glazing of walls and blind sections of the facade, while glazing of walls and windows can be performed in the same plane. Such constructions have been mastered by firms producing ventilated facades, and are fastened with brackets to the outer wall. They are made similarly to conventional non-transparent ventilated facades with an air gap. They are often used in architectural solutions of modern buildings to create the impression of solid glazing. The glass surface above the walls plays a decorative role, and covers the insulation from external influences. The external joining consists of strips 75 and 80 mm wide.
These systems can be used in conjunction with any other (perforated, tape and other glazing) for cladding blind areas.
Double facades (Fig. 4) imply continuous glazing, but differ from those discussed above in that they have the main - inner and additional - outer layers of glazing. The inner and outer layers of the facade are arranged at different distances from each other, which can be from several decimeters to 2 meters. At the same time, the additional outer layer, as a rule, has a single glazing and serves as protection against gusts of wind, precipitation and the sun. It can be fitted with opening frames and sun blinds. The main inner layer has double or triple glass units, it can be made in the form of a facade with solid, tape, perforated glazing, or any other system.
However, one cannot fail to mention a large number of critical materials about these decisions [1].
Classification of translucent facades by design solutions allows distinguishing the following groups: support-transom, frame, spider, structural, semi-structural, ventilated and warm-cold ventilated, panel.
The supporting-transom structure consists of vertical supports and horizontal lintels - transom, assembled on site. The load-bearing structure remains on the inside warm side. Installation of this structure is a rather complicated operation. The filling elements, that is, all insulating glass units, panels and fasteners, are delivered separately and assembled on site. The installation process is carried out outside the building. As a rule, erection of scaffolding is required for installation. In case of bad weather conditions, assembly becomes much more difficult and the likelihood of making mistakes increases.
These designs are used for facades with perforated, strip, solid glazing, as well as for ventilated facades with glass cladding. In addition, they can be used for glazing winter gardens, translucent roofs, domes.
The frame structure consists of a frame formed by vertical supports and horizontal lintels, into which prefabricated glazed frames are inserted. The supporting structure remains partially outside and must be insulated. The design has a number of differences from the support-transom, the main of which is that the installation and glazing (installation of frames) is carried out from the inside. Taking into account the factory readiness of frames, we can say that weather conditions have much less influence on the assembly process.
These constructions are used for facades with solid glazing, with perforated and strip glazing, as well as for double facades.
Structural glazing is based on a method of installing glass and insulating glass units, in which the frames are not visible on the outer plane of the facade, due to which the effect of a continuous glass surface with inconspicuous seams is created. Glasses or double-glazed windows are glued to an aluminum frame inserted into the support-transom frame, or directly to the supporting frame. In this case, window panes (double-glazed windows) are closely adjacent to each other and are attached with glue from the outside without visible fastening tapes or other fixing elements. The supporting frame remains on the inside warm side. The installation process of double-glazed windows is carried out outside the building. As a rule, erection of scaffolding is required for installation. In case of bad weather conditions, assembly becomes much more difficult and the likelihood of making mistakes increases.
It is used for facades with solid glazing, as well as for ventilated facades with glass cladding, with perforated glazing and strip glazing. It should be noted that these solutions are considered dangerous and are practically not used in a number of countries, including Germany [2].
Semi-structural glazing differs from structural glazing in that each glass unit is framed by a fixing aluminum edging, visible from the outside, which prevents the glass from falling if the adhesive is damaged.
It is used for facades with solid glazing, as well as for ventilated facades with glass cladding, with perforated glazing and strip glazing.
Spider glazing is a new solution for glazed facades. Based on the use of a frame formed by vertical supports and horizontal bridges, into which double-glazed windows are inserted. Sealing is achieved by filling the space between the glass units and the frame with a special silicone sealant. The insulating glass units themselves are held on special brackets - spiders, which are attached to the supporting frame.
It is used for facades with solid glazing, as well as for ventilated facades with glass cladding, in blind areas with perforated and strip glazing.
Warm-cold ventilated facades are a variant of ventilated systems and are used where there are blank sections of walls that do not require thermal insulation of the entire surface. The glass surface above the walls serves only as a decorative role. In this case, a lightweight frame can be used without thermal break (special measures to reduce heat loss through the supporting elements of the frame), which simplifies the design and reduces the cost of the facade.
It is used for ventilated facades with glass cladding, on blind areas of walls (ends, walls, etc.).
Panel facades are produced in workshops in the form of ready-to-mount fragments. They already include a frame with installed double-glazed windows and openable elements. Such facades are distinguished by the shortest production and installation times. The installation process is carried out outside the building. As a rule, erection of scaffolding is required for installation. In case of bad weather conditions, assembly becomes much more difficult and the likelihood of making mistakes increases.
It is used for facades with solid glazing, as well as for perforated glazing and strip glazing.
The classification of materials for the structures of glazed facades provides for the division into the following groups: aluminum, steel, combined.
Aluminum profiles are usually made of "three-component alloy" aluminum, magnesium, silicon and have an anti-corrosion coating. Aluminum has a high thermal conductivity, so usually all manufacturers produce two types of profiles: "cold" and "warm". "Cold" profiles are not suitable for heated building facades. "Warm" profiles have a heat-insulating insert in their design, which provides better thermal insulation of the profile. The insert is made of glass fiber reinforced polyamide. To improve thermal and sound insulation, it can be made of polyurethane.
The decorative finish of the profile is provided by anodizing, powder painting and imitation of the surface of various materials, while the shape of the external overlays can be very different - flat and box-shaped, semicircular and lenticular.
Steel profiles have long been used in our single binding. Now they have been replaced by a new generation of steel facades, which in terms of resistance to thermal conductivity, corrosion resistance, design is not inferior to aluminum facade systems, and has significant advantages in price. As well as aluminum, steel profiles can be "warm" and "cold".
Decorative finishes are carried out with various types of paint, which provide ample opportunities in terms of color, texture and texture.
Combined profiles are similar in appearance to PVC profiles, which are well known to everyone from plastic windows and doors, but from the inside they are reinforced with a reinforcing steel profile. The advantage of the facade of such structures is the possibility of using plastic windows.
Another option for combined structures is the combination of a steel frame and an aluminum profile. When large spans need to be glazed, it often becomes economically feasible to install a cheap steel frame onto which to anchor the aluminum structures, thereby increasing their rigidity.
Decorative finishes for aluminum and steel surfaces are similar to those discussed above (see decorative finishes for steel and aluminum profiles). For PVC profiles, finishing is provided by lamination and due to the ability to simulate a large number of options for such properties as texture, texture and color, a wide variety of materials (wood, metal, stone) can be copied.
The choice of an architectural solution for a translucent facade cannot be random or based only on aesthetic preferences. Different types of buildings have their own criteria in the use of facade glazing, of which the most important should be considered functional.
For example, in residential buildings, due to the peculiarities of planning solutions, strict heat engineering, fire safety requirements and traditional economy, solid glazing is used only for fencing balconies, lower floors with public premises and winter gardens on the roofs. Sometimes it can be used for living rooms of representative apartments and apartments. In ordinary living rooms, however, traditional windows are installed. Solid glazing is completely inappropriate in a bedroom that requires a cozy and intimate setting. Consequently, for residential buildings, you can use facades with strip and perforated glazing, a ventilated system with glass cladding, as well as double facades, the inner layer of which may not have solid glazing, but ordinary windows with walls and a window sill.
The architecture of public buildings, including offices, banks, shopping, sports and entertainment centers, on the contrary, tends to significantly increase the area of glass facades. They are suitable for façade systems with perforated, strip and solid glazing, as well as double fronts. However, glazing the entire outer wall is not always appropriate in a public building. It is most in demand in prestigious premises, but not necessary or even appropriate for ordinary work rooms.
Multifunctional buildings that include different premises in their volumetric-spatial structure - housing, hotel rooms, office premises - represent the most difficult task in design. On the one hand, the facade surface should be subordinated to a single architectural idea, therefore, the glazed facade of such a building, as a rule, is a common glass wall. When implementing such an idea, a double facade is most appropriate. At the same time, it is possible to organize a combined facade, taking into account the difference in lighting requirements for premises for various purposes - apartments, hotel rooms, offices.
The choice of a constructive solution and materials for translucent facades is based on their architecture, the possibility of using these structures in a particular case. This takes into account the parameters of the facade and their impact on the economic feasibility of certain structures. In addition, an important factor is the installation process, which requires scaffolding, or allows all work to be carried out from the inside of the building, which can be decisive in adverse weather conditions. The dimensions of structures, the need for their reinforcement determine the choice of material for profiles, frame and frames.
Summing up, it should be said that the use of translucent facades in the design requires consideration of a number of issues. One of the tools to help you make a decision is classification. It takes into account the positive and negative properties of the structures under consideration and the appropriateness of use for buildings for various purposes.
Following the method of transition from the general to the particular, first of all, it is necessary to determine the type of facades, using the classification according to the architectural solution, which allows taking into account the architectural and planning and architectural and artistic requirements for them. The next stage of design is the selection of possible options for facade structures, based on the classification by design solutions. Further, taking into account the design requirements and operating conditions, the materials of the supporting structures and the type of glass are assigned. Thus, the systematization of various architectural and structural solutions of glazed facades allows architects, developing the architectural and artistic appearance of modern buildings, to create the desired compositional structure, take into account the urban planning environment, the architectural and planning solution of the object, as well as the nuances arising from the interconnection in a single architectural solution of functional, constructive, technological and artistic issues.
Cand. arch., prof. A. A. Magai;
Cand. Arch., Assoc. N. V. Dubynin
(The article was published in the periodical Vestnik MGSU - 2010 - No. 2)
Literature:
1. Getis. K. Double glass facades (beginning) // ABOK. 2003. No. 7. S. 10-17.
Getis K. Double glass facades (continuation) // AVOK. 2003. No. 8. S. 22-31.
Getis K. Double glass facades (continuation) // AVOK. 2004. No. 1. S. 20-23.
2. Guide to high-rise buildings. Typology and design, construction and technology. Per. from English Moscow: OOO Atlant-Stroy, 2006.228 p.
