КОНЦЕПТ „КРУЖНЕ ВЕЗЕ” У СТАМБЕНОЈ АРХИТЕКТУРИ “CIRCULAR CONNECTION” CONCEPT IN HOUSING ARCHITECTURE

Кружна веза је један од есенцијалних концепата у организацији стамбеног простора. Најчешће подразумева формирање непрекинуте комуникације у оквиру система ланчано надовезаних просторија. Примењује се у ситуацијама када се жели постићи већи ниво просторности у условима малих квадратура, при чему се умањује или неутралише осећај скучености простора, али и код већих квадратура с циљем јасног диференцирања или повезивања удаљених функционалних зона. У науци још увек није евидентирана прва примена кружне везе у историји, мада се са сигурношћу може тврдити да су најранији примери постојали још у периоду средњег века, а наговештаји чак вековима уназад. Циљ рада је ситематизација различитих појавних облика кружне везе који су присутни у теорији и пракси, као и преиспитивање различитих повода који могу да доведу до њене примене.


THE ORIGIN AND THE DEVELOPMENT OF CIRUCLAR CONNECTION IN HOUSING ARCHITECTURE
So far, science has been unable to confirm the exact time when the concept of circular connection appeared for the first time in housing architecture, although it is assumed that the application of circular movement had been utilized as far back as in ancient cultures in the context of religious ceremonies (Kehnel, Mencej, and 2009:67).We could assume that a very faint reference to the circular connection in housing architecture could be found in the Hellenic house with a portico (a corridor with a roof top) around central yard, which served as the example for further development of the Roman house, the so-called domus (Graham, 1966:4).Both examples showcase continuous communication in the zone with a roof structure, which, among other uses, also serves for direct connection of peripheral rooms (Fig. 2).In the XV and XVI century, Italian renaissance palaces had the concept of circular connection in the form of directly adjoining rooms forming cyclic rows.Unlike other housing shapes from the same period, there are numerous examples of Renaissance palaces with doors that showed no particular purpose but to allow the user to move undisturbedly from one room to the next, thus pushing the limits of privacy.Among other, architecturally well-known examples are Palace Farnese, Strozzi, Riccardi-Medici, etc.With circular connection applied only in certain segments of the building, in Piccolomini palace, Pienza, by Bernardo Rossellino, 1459 it appears in its full form.The next significant example is famous Villa Rotonda in Vicenca,  By looking up to ancient role models, an Italian architect and theoretician Leon Battista Alberti in his tractate "Ten Books on Architecture" points out that the door of the house should be appropriately positioned so as to connect as many rooms as possible (Evans, 1997:63-64).The same attitude was taken in architecture up until the emergence of corridor, at the end of XVI which represents one of the significant turning points in functional organization of architectural spaces.The corridor, as an autonomous space for communication and connection of other rooms, enabled privacy level to be raised to a higher point, by neutralizing numerous doors separating living rooms.2On the other hand, the application of corridor made it easier to differentiate rooms for servants from drawing rooms and living rooms (Colmenares, 2017:60;Grikevicius, 2015:20), and this remained an important principle up until the beginning of the XX century, and up to a point is present even nowadays.Иако је примена коридора током XVI и XVII века била све присутнија у стамбеној архитектури, принцип кружне везе није у потпуности укинут, већ је у периоду барока, у архитектури резиденција и палата, добио сасвим другу, естетску димензију.Тада су се јавиле прве анфиладе или позиционирање просторија, врата и прозора у дуге аксијалне низове, чиме су постизани драматичнији визуелни ефекат и хијерархија простора, док су кружне везе постале издуженије (Ching, 2007:413) (Connors, 1984:36;Elliott, 2002:53).(Сл.6) Уместо традиционалног приступа сегрегацији стамбених просторија солидним зидовима, Рајт је границе између простора диференцирао тако што је увео дрвене параване, завесе, велики број стаклених врата и прозора.Иако просторије нису обједињене у компактну целину, чиме би јасније био формиран једнопростор, већ се стиче утисак њихове континуалне повезаности и преливања у виду кружне везе, концепт текућег простора је пружио снажан подстицај за даља истраживања у области хабитологије (Alfirević, Simonović Alfirević, 2016a:48).
Although the use of corridors during XVI and XVII century was more present in housing architecture, the principle of circular connection was not completely eliminated but acquired a different, aesthetic dimension in the period of baroque in architecture of residences and palaces.This is when the first enfilade appeared-the positioning of rooms, doors and windows into axial suits, which achieved a more dramatic visual effect and achieved hierarchy of space, while circular connections became elongated (Ching, 2007:413).(Fig. 5) A particularly important moment in functional organization of space was the emergence of open-plan concepts in the middle of XIX century and flowing space at the beginning of XX century (Alfirević, Simonović Alfirević, 2016a:48;2016b:28), which led to the "dilution" of firm definition of circular connections and aberration of their axial definition.The construction of Darwin-Martin house, 1903-1905in Buffalo, Meyer-May house, 1909 in Michigan and Robie house, 1910 in Chicago, by architect Frank Lloyd Wright, marked a significant, qualitative progress in living space organization, as they were the first examples using the concept of the so-called flowing space (Connors, 1984:36;Elliott, 2002:53).(Fig. 6) Instead of utilizing the traditional approach to segregation of living space by solid walls, Wright differentiated the borders between spaces by introducing wooden screen partitions, curtains, numerous glass doors and windows.Although the rooms were not joined into a compact unit, which would, more clearly, form all-in-one-space, giving the impression of being continually connected and flowing into each other through circular connection, the concept of flowing space offered a firm stimulus for further research in the habitology area.(Alfirević, Simonović Alfirević, 2016a:48).
Unlike the open-space concept, which unites the rooms into all-in-one-space, as a consequence of the inclination towards physical enlargement and achievement of larger space comfort, the application of circular connection is aimed towards achieving the feeling of wider space, while at the same time contributing to the higher quality of the flat itself, lowering За разлику од концепта отвореног плана, код кога је обједињавање просторија у "једнопростор" (all-in-one-space) настало као последица тежње ка физичком проширењу и постизању већег просторног комфора, примена кружне везе је усмерена, првенствено, ка постизању доживљаја веће просторности, с тим да доприноси и подизању општег квалитета стана, смањењу некорисних комуникацијских веза и бољем кориштењу укупне расположиве површине стана за социјалну интеграцију чланова породице (Knežević, 1986:33) useless communication connections and leading to better utilization of total usable flat area for social integration of family members (Knežević, 1986:33).Combining the circular connection and open space plan by the beginning of XX century, influenced the appearance of flowing-space concept which unites characteristics of both principles.The mentioned concepts nowadays make up the basis of contemporary functional organization of living space.

CHARACTERISTIC TYPES OF CIRCULAR CONNECTIONS IN HOUSING ARCHITECTURE
Analytical insight into numerous examples of circular connections present in the history of architecture, makes it possible to distinguish several characteristic types, grouped according to the following aspects (Fig. 7): • character of the path (formal aspect): In determined circular connection of open type, communication in certain segments opens towards the extrior, most often in places where the direction of movement is changed, which, more than in previous types, creates the impression of larger space.The inclination to open the inner space towards the exterior setting primarily depends on the attitude of the architect himself, but also on the context in which the house had been set.The directions of views towards the exterior can have their base in static positions of the users (sitting on a sofa, at a desk, working in the kitchen, etc.), but can also be an integral part of active usage of the space, as is the case in moving around the living space or other activities taking place within this space.The importance of opening the circular connection is primarily reflected in the option to limit the space conditions and achieve the illusion of wider or even limitless space.Generally speaking, there are three ways to achieve horizontal openness of circular connection: by using sideways opening related to the direction of movement, b) by axial opening along the direction of movement, and c) by applying a combined opening, which offers the opportunity to change the view at any given moment.
In the Black Pyramid House, in Toyama, by Yukihide Mizuno, 2007, sideways views towards the exterior were applied, which placed in the background the option of directed visualization of the surrounding space, while the primary importance was placed on the cross-section connection of the central yard of the house with its surroundings.In case of elongated land lots and objects, which are characterized by dominant one direction of movement inside the circular connection, it is customary to have axial opening along the direction of the main axis of the object, as was the case in "La Maison Etirée" in Lyon, by Barres & Coquet, 2011.Less frequently, in cluster buildings 3 , with structure of inner rooms enabling the opening the interior into two or more directions, it is possible to establish circular connection or the whole system of circular connections with 3 Cluster buildings are groups of buidligns or rooms within one building, positioned at a near distance, so they can be viewed as clustered group of independent rooms or as a whole.Their segmentation enables the possibility of visual connection between the interior and the exterior.
Сл the authors formed the system of circular communications with extensive views in several directions, aiming to integrate the natural setting as much as possible with the interior of the house (Fig. 9) The system of determined circular connection includes complex combinations of several circular communications into all-in-one system, where these communications are linked or intertwined.
It is usual to differentiate the circular connection which connects daily functions from one or more communications connecting night space into a whole, as is the case in apartments in Felix & Regula buildings in Zürich, by Loeliger Strub Architektur, 2012.
A similar principle was used by the team Aires Mateus, 2000 in House in Litoral Alentejo, Alentejo, 2000.The team formed multiple circular communications inside the interior, with hierarchy established on the primary connection which serves as a frame for mutual space and the secondary connection, between rooms and utility rooms.The reasons to form the system of circular connections can vary from the ones we mentioned previously those leading to the reconstruction of the apartment in Boston Outside-In Loft, by Howeller+Yoon, 2008.
In order to unite two apartments into one unit, they formed the main circular connection along the outer sides of the apartment and the secondary connection adjoining the primary one.(Fig. 10) Free circular connection stands for the option of forming numerous different trajectories of movement within the same space, which can be achieved by constant circulation, wider space profile and loosely defined boundaries of circular connection.In conditions of unobstructed movement, with no barriers such as doors, which normally form the places where one leaves one space and enters a different one, circular connection gains free character.Movement in space is no longer strictly defined by constant width of the profile, but by its variability as it offers the option of emphasizing not directed movement, but visualization and the feeling of elements in the interior.In Light Walls House, mA-style Architects, in Toyokawa, 2013, this concept was used as the primary concept of space organization, Primary circular connection is constantly present between the study rooms, living rooms, dining room, atelier, staircase and the kitchen.A potential circular connection can very rarely be formed by connecting the bedroom, walk-in closet, bathroom with atelier, dining room and living room.The reason that explains why this type of connection does not have a different character lies in the fact that direct connection of bathroom, as the intimate space, with the atelier, which serves as the working space and the area where clients are being seen, can lead to functional conflicts, which requires that this space can be controlled.(Fig. 12) Taking into consideration the aspect of functional interconnection of two or more circular connections, depending on their hierarchy or significance in the apartment structure, they can be classified as primary or secondary, i.e. independent or dependent.A primary circular connection is autonomous and independent, with its own continuity and frequency.Most often, it is used in housing spaces with noticeable need for connection of most frequently used rooms, such as living roomdining room-kitchen, study room-drawing room-living roomdining room, entrance-living room-dining room-kitchen, etc.The functioning and the continuity of the secondary circular connection depends primarily on the existence of the primary connection that precedes it.A secondary connection appears between rooms with no need for frequent connection, which is why the secondary connections appear mainly in situations when it is necessary to connect the living space with additional/ utility spaces or addition utility space with the same kind of space.Although in this paper we mentioned only individual representative examples of circular connections, in practice, numerous variation of mixed combinations are present, which makes this topic inexhaustible for further research.

CONCLUSION
Along with numerous forms that circular connection can have in a living space, what is of primary importance for further theoretical research and practical use is its role or purpose in functional and spatial organization of the living space.It is important to stress that the most frequently stated reasons for circular connection use in housing architecture are as follows: A) Functional reasons: 1.The inclination towards a clear differentiation of functional zones in the living space i.e. the separation to dailynightly rooms, living space-additional units, generational differentiation, etc.The circular connection usually separates into independent units (cores) spaces such as sanitary area, staircase, pantry, utility rooms, den, kitchen, bedroom, etc. 2. The aim to achieve better connection of functional units which without circular connection remain too distant from each other.By introducing additional circular connection some rooms, such as bedrooms, kitchen, and balcony, loggia, even bathroom and lavatory achieve the necessary flow, which in some situations reduces the level of privacy and creates functional problems.3.In order to achieve higher safety in case of attacks (found in the past in palaces and residential buildings) and the ability of evacuation in cases of fire, the dead-end structures were avoided.B) Aesthetic reasons: 1.The aim to visually stress and envisage the motives in space.
The motives could have been different-from free standing walls as in Mies van der Rohe's projects, through blocks of furniture and communications (a row of cupboards, shelves, staircases, elevator, etc.), up to free standing rooms or groups of rooms (technical core and utility rooms).2. The aim to achieve higher spaciousness and to minimize the experience of the space being crammed.By establishing circular connection and the system of circular communication in the apartment, the space flow, as well as comfort ae achieved, and at the same the feeling of claustrophobia is being prevented.

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Fig.6The application of open-space and flowing space in Darwin-Martin house(Buffalo, Frank Lloyd Wright, 1903-05)  and the Glass house, New Canaan(Philip  Johnson, 1949) Fig. 7 Schematic representation of characteristic types of circular connections: 1) determined circular connection of closed type; 2) determined circular connection of open type; 3) a system of determined circular connections; 4) free circular connection; 5) constant circular connection; 6) occasional circular connection; 7) potential circular connection; 8) primary circular connection and 9) secondary circular connection.