The influence of rapid industrialization on housing
problerns in Yugoslavia
UDC 338.01 .I31 (497.1) : 728
1
J. V U K O V
Chief of the House Building Section of the Centre for Iniyrovement of Building (Yugos/avia)
There is a great number of agricultural, overpopulated countries with coinparatively poor
populatioi-is. This is one of the hardest problems to solve from the social, human and political point of view. In most cases these countries have available ample raw materials, so that
actually they are not passive but only uncultivated. Partly by their own efforts, partly
with the technical assistance of the United Nations, many of these countries are on the
way to iniprove their economy according to the specific characteristics peculiar to each
of them.
Yugoslavia is one of these countries, undertaking great efforts to develop its economy by
its own efforts. From a backward agricultural country with a comparatively poor rural and
urban population, Yugoslavia has reached an intermediate stage of economic development
which has made it possible to triple its national income in the post-war period and to become
stroi-igand independent.
On the way Yugoslavia had to solve many complex probleins facing all the underdeveloped countries that Start towards economic emancipation. Hence, the example of Yugoslavia
undoubtedly presents an experience beneficial to them.
Whatever the scope of the present report, we must give soine essential data concerning the
economic basis of Yugoslavia after the Second World War in order to permit a correct
appraisal of past and present difficulties and to encourage those countries that have a better
economic background than Yugoslavia in their efforts towards a progressive economic
development similar to that of Yugoslavia.
ECONOMIC BACKGROUND O F YUGOSLAVIA
Before the Secorid World War 80 per cent of the Yugoslav pop~ilationearned its living
through agricultural activities. Small rural pieces of land were cultivated with primitive tools,
so that farmers were unable to employ all the members of their family. In most cases the
farmer did not own his land, the real owner being his creditor.
Foreign capital was not largely invested in this country because of its unsound economic
background. Various branches of industry were highly underdeveloped and unable to absorb
the national iricrease of population, in parlicular rural population, amounting to 200,000250,000 a year.
The Second World War brought the country - to begin with, not economically sound into a very bad situation in maiiy respects. Ten per cent of all tl-iedwellings were demolished,
railway trafic routes completely ruined and more than 95 per cent of bridges totally
destroyed, not to enumerate other unpleasant events of the past.
After the war no peace treaty was signed and Yugoslavia had no means of obtaining
adequate reparations for enormous war dainages.
This was the economic position when Yugoslavia started on its way towards economic
emancipation relying mainly on its own resources.
AVAILABI LITY O F DWELLINGS BEFORE INDUSTRIALIZATION
The Second World War seriously reduced not only the population of Yugoslavia but also its
available dwelliiigs. Thus the figure which indicates the available useful dwelling area per
person has, in spite of destruction, remained the Same, viz. 12 m2 per person.
Not more than 5 per Cent of the available dwellings were of a high standard and comfort;
the rest were old-fasliioned dwellings with little coinfort and often without any elementary
provisions to meet up-to-date requirements concerning lighting, heating or sanitary installations.
INCREASING
NEED
FOR
DWELLINGS,
CAUSED
BY
INDUSTRIALIZATION
Owing to the bad economic conditions resulting from the war damage as well as from the
prevailing pre-war social system, Yugoslavia was faced with a number of serious problems in
building, i.e.
1. Reconstruction of the country.
2. Establishment of new industries.
3. Housing.
For the constructioii of dwellings Yugoslavia is speiiding 5 per cent of its national income,
which corresponds to the average amount expended by many other European countries.
However, whilst Norway is spending about 6 per Cent of its national income and produces
10 comfortable dwellings for eacli 1,000 inhabitants, Yugoslavia could, according to the
first five-year plan of development, erect only 2 dwellings for each 1,000 inhabitants with
its 5 per cent proyortion. This fact gives evidence of the bad ecoiiomic condition of the
country immediately after the Second World War.
The speedy industrialization of the country, on the other hand, has caused an iiiflux of
about 27 per Cent of the rural population into towns and production centres, a trend badly
aggravating the prevailing housing shortage. As a result, the figure of 12 m2, whicli indicates
the available dwelling area per inliabitant, went down to 8.6 m2 in 1956, when the housing
shortage was at its peak. Since then, owing to the econoinic recovery, the housing standard
has tended to improve and in 1960 the above figure had risen to about 9.0 in2.
TECHNICAL AND ECONOMIC MEASURES AND THE
ROLE
O F
THE
COMMUNITY
The favourable economic developmeiit of tlie country has made it possible to implement
ambitious plans for the constructioii of dwellings in the forthcoming period of 1961-1980,
with tlie aim of putting an end to the housing shortage in Yugoslavia by that time.
The following aims characterize these plans:
(i) Provision of funds for the modernization of the existing building materials and equipinent industries as well as for the establishmeiit of new ones.
(ii) Accelerated introduction of new methods of construction, i.e. prefabrication to the
largest possible extent of building components.
(iii) Large-scale development of scientific research work in the building industry.
THE ROLE O F SCIENTIFIC RESEARCH INSTITUTIONS
The activities undertaken by various institutes and centres to promote building are of great
importance both for the produciion of building materials and elements and for the design
and erection of buildings. The Progress achieved in the improvement and prefabrication of
housing results mainly from the work of these institutions and of specialists engaged in
various branches of industry. Twenty-two independent institutions, centres and laboratories,
employing 785 civil and other engineers, technicians and laboratory assistants, have been
engaged in scientific research and analytical studies.
Mention can be made of the institutes at Belgrade and Ljubljana, which are well equipped
and staffed, so that research, studies and investigations, testing of materials and structures,
all aimed at meeting the requirements of the industry, are carried out successfully.
In addition there exist similar institutions attached to the universities and technical
colleges. These are primarily teaching institutes but they are also concerned with development
in the field of science and with the implementation of various economic assignments.
In design offices, biiilding firms and the building materials industry, generally there is no
permanent activity directed towards the improvement of production, but particular investigations have been carried out in relation to specific problems.
The work of the institutes at Ljubljana, Zagreb and Belgrade is of particular interest, since it
deals, either wholly or partly, with the testing of building materials and structures, the promotion of housing technology and other construction, the introduction of new varieties of
materials and units and, in general, the acceleration of the transition to industrialized
construction.
The activities of institutes concerned with the improvement of housing are generally
directed towards the modernization of traditional construction by an ever-increasing application of semi-prefabrication. In most cases the load-bearing structure is built in situ and only
in some cases is it partly assembled in the factory. By applying these construction niethods,
the other elements of a building, such as floors, stairs, etc., are prefabricated. In addition, the
instit utes are concerned wit h the pron-iotion ai-id increased application of semi-prefabrication,
based generally on reinforced concrete and occasionally on other materials, of small-sized and
lightweight prefabricated elements such as panels with doors and windows built in and with
surface finishings, and of lightweight partition walls with surface finishings. Thin facing
slabs made of gypsum and other materials are mounted on the walls instead of being plastered. Various slabs made of plastics (floors, ceilings, prefabricated sanitary installation
blocks, etc.) are also mounted. The System of full prefabrication in housing is very rarely
applied in our country at the present time.
In the field of research work and studies ii-i Yugoslavia, recently there has been carried out
a thorough re-organization in regard to unity of purpose and action, so that all the research
work concerning improvements is planned and directed from one central point, i.e. the
Federal Council for Research, in which are represented all the interested scientific institutions ai-id, in particular, the Federation of Yugoslav laboratories. The main assignment of the
Federal Council for Research is to encourage scientific and research work in all fields that
contribute to the solution of the general development problems of our couritry, and, as well
as this, to give recoinmendations to scientific institutions for solving specific technical and
economic questions of importance for the improvement of the economy. The Federal Council for Research is the body responsible for the financing of study and research in Yugoslavia
and the funds available are, therefore, spent by the Council with a view to promoting the
economy of the country.
The Centre for the lmprovement of Building attached to ihe Federal Chamber of Building
has had an exceptionally important and progressive role in the promotioi-i of building and,
particularly, housing.
In order to establish a basis for standardization in housing, as a condition for increased
prefabrication and consequent accelerated cheaper construction, the Centre has set up
special committees, which, on the basis of the 10 cm module adopted in Yugoslavia in 1958,
have laid down the following standards:
furniture in dwellings,
kitchen elements and appliailces,
public and individual laui-idries,
ba throom appliances,
modular slag concrete blocks for masonry,
modular sizes of lifts.
In addition to the foregoing, the Centre has drawn up the 'Federal Rules of Obligatory Application of Modular Coordination in Housing', as well as the 'Instructions for the Design of
Dwellings iii accordaiice with the principles of Modular Coordination'.
The application of these rules has shown good results in the design of dwellings, in the
production of building elements and in construction work.
THE ROLE O F THE BUlLDlNG MATERIALS AND
APPLIANCES
INDUSTRIES
The production of building inaterials and appliances in Yugoslavia, after the Second World
War, was primarily directed to meeting requireinents for the execution of industrial and
other economic projects of major importance. In the early years after the war and up to 1955,
liousing was a field where building materials aiid equipment were not used to any great extent. Since 1955, Yugoslavia has started an intensified programme of housing.
New industrial capacity has at the Same time fostered the development of a new
building materials and equipmeiit industry.
In comparison with the pre-war period great improvements have beeil made in the production of building materials and equipment; without this Progress, it would not have been possible to carry out the immense construction programme in Yugoslavia during the 15 postwar years.
The rise in the production of building materials and equipment has been promoted by the
increased scope of construction in the field of all social activities.
The inain characteristics of the production of building materials and equipment are the
higher level of production and the wider range of both type and quality of materials
prod uced .
Because of the great increase in the scope of construction works the available stocks of
building materials and equipment were, in the earlier periods, often drastically reduced and
this brought about a reduction in the speed and quality of construction. However, as has
been stated above, the increased production of building materials, particularly during the last
five years, has improved the whole position. Moreover, it must be admitted that the technical
level of the building materials industry here does not yet permit the full development of the
modern and more econoinical building systems using the materials which have been applied
extensively in more advanced countries.
The programme of housing in Y ugoslavia in the 196 1 - 1965 period embraces the construction of 500,000 flats. In conformity with this programme the industry has started the mass
production of new building materials, which should speed up the industrialization of construction in general and of housing in particular.
Among others, following articles are now being produced, and many of thein are in
agreement with the adopted 10 cm module:
lightweight concrete, Siporex type,
foamed slag bricks,
reed slabs,
gypsum slabs,
Stramit slabs (made of pressed straw),
expanded clay,
hydrated lime,
lightweight wood-fibre building slabs,
Durisol,
masonry blocks of slag-concrete,
special iilortars for rendering facades,
hollow clay bricks,
asbestos vinyl floor slabs,
monolithic plastic floor finishes,
synthetic linoleum.
Tlie production of various types of housing equipment includes numerous appliances which
facilitate housework.
Dimensional standards for furniture in dwellings, evolved by the Centre for the Improvement of Buildiiig, attached to the Federal Chamber of Building, have enabled the equipment
and furniture industry to start mass production of diniensionally standardized units.
Designers and users are, by these standards, given a safe starting point for a versatile and
rational lay-out of dwelliiigs.
In addition, the niass production of furniture has enabled tlie industry to manufacture
furniture which corresponds in price with the buying capacity of the population.
The general belief is tliat our building materials and equipment industry is able to provide
all the necessary appliances and installations to meet the requirements of an iiitensified housiiig progranline.
THE ROLE OF THE DESIGNER
With a view to improving tlie building system iii our country, the design of dwellings and
other buildings must, according to the conceptions of our designers, be based on a general
form of standardization and, in particular, on the standardization of prefabricated components of buildings, dimensionally iii agreement with tlie principles of modular coordination. The important point here is that the range of these components should be held
within reasonable liniits in order to allow for econoinical solutions and harmonious
architectural design.
In addition, our point of view is that the prevailing circumstances do not allow the
abandonment of traditional constructional methods if the housing programme is to be
achieved, but the developn~entof traditional methods should be promoted by infiltrating as
great a number as possible of prefabricated elenients, aiming at a gradual transition to
industrialized construction.
In order to carry out this ambitious housing and building programme, large design
offices liave been established in the capitals of the republics. Such a systern of concentrated
offices suited the requirements of designing large projects for our economic development.
The concentration of desigii work carried out in large design ofTices and institutes had a
positive effect on the professional training of the staff engaged in designing. Thus, in our
country there are efTicient organizations for the design of dwellings aiid industrial and other
buildings.
The good results obtained in our country reflect the ardour and the creative activity of the
designers wlio, nowadays, must take into account not only the usual priiiciples and conditions to be fulfilled by a good designer, i.e. functional, economical and aesthetic design, but
also a new elenieiit of importance, i.e. to include in the design as many industrially produced
building components as possible.
The construction of towns and localities is carried out in accordance with the overall
concept of town planning, which is one of the prerequisites for an adequate solution of housing
problems and housing policy.
The main task of town planning is to determiiie the territorial boundaries of localities and
to reconstruct towns and localities by meaiis of progressive changes in the inherited structure
of towns, and also to remove the differences existiiig between tlie centre of the town and its
suburbs, between the town and the village.
THE ROLE O F THE CONTRACTOR
In order to obtain a better appreciation of the role and the development of building firms,
it should be realized that building activity in Yugoslavia between the two world wars was on
a much lower scale both in scope and, i i i particular, in complexity and technical treatment of
structures than in the period from 1945 to the present.
In 1945 there were almost no building firn~s,niachinery and plant were lacking, and the
number of qualified professional staff was greatly red~iced.
Oiily a Part of the technical staff had economic, professional and organizational experience.
In 1945, the capacity of the constructional industry could be increased only by employing a
very Iarge labour force. The newly organized f i r m became strong building organizations
which executed almost all the projects required ior the industrialization and electrification
of the country, as well as for traffic routes. Professional, economic, technical and organizational experience was acquired during the organization and the execution of the projects
involved.
From the various specialized activities carried out so far, groups of building enterprises
have developed, covering the construction of general architectural buildings, various industrial buildings, civil engineering structures, etc.
The manufacture of building plant could not be developed before the metallurgical
industry and tlie necessary machine industry were established. During the last three years
there Iias been a considerable rise in the production of building plant. Quality has been irnproved, quantity and variety increased.
Iii addition t o the b~iildingenterprises responsible for the construction of the main carcase
of the building, including the calculations involved (statics and otherwise), about 25 different
kinds of building-craft enterprises are responsible for the execution of the so-called finishing
works. Soine of them manufacture and erect meta], wood and stone elements, some erect
installations necessary for the functioning of buildings and other completed projects and some
deal with the final treatment of internal and external surfaces.
The average value of these works with buildings of the usual standard amounts to
approximately 47 per Cent of the total value of the project. For a building requiring special
finishing treatment, this value amounts to 50 - 60 per Cent. Furtherrnore, it rnust be pointed
out tliat the tralisition to a more industrialized method of construction brings about a new
position concerning the labour employed, i.e. the division of the labour force according to
the qualifications of workers and the kiiids of trade (bricklayer, carpenter, concrete worker,
etc.) is now no longer relevant. Therefore, it is necessary to train a new type of worker - a
specialist assembly worker whose task is to erect the prefabricated components of a building
as well as the prefabricated elements for installations.
The remainder of the paper is devoted to the technical and economic results of coordinated
efforts towards the industrialization of house building in Yugoslavia in order t o solve the
housing problem of the country.
Z I D 0 B: 7he systen? of'senii-prefabrication used in the construction of Jats and houses executed by
'Gradis', Ljubljana
This system is based on the principles of modujar coordination with firm standardization of
prefabricated elements. Its characteristics are as follows:
Interna1 load-bearing walls are made of hollow slag-concrete 20140 cm blocks which are
erected dry to a height of one storey; the core is then filled with concrete. The walls are tied
into one structural unit with floor constructions and with external and staircase walls.
External walls are of flat slag-concrete blocks, allowing a minimum use of mortar.
Partition walls are of lightweight concrete blocks (d - 6 cm). The staircase is shaped and
supported by two standardized prefabricated beams. The floor construction is semiprefabricated and composed of concrete beams and hollow lightweight filling elements. All
lintels are prefabricated. Horizontal ducts and bathroom installations are built in in prefabricated panels. The ventilation is also built in in the panels in the form of ro~indducts.
Chimney flues are of 'Shunt' type.
PBM
S Y S T E M : Pvefabrication bjt the huilc(ii~gpvn?
'Gradis', Ljubliana
The PBM system of prefabrication comprises the following stages:
1. External and partition walls are mounted on a traditionally constructed basement
concrete slab.
2. Hollow blocks (of graded slag) are laid dry to one-storey height.
3. Floor construction is laid.
4. The hollow blocks are filled with concrete, giving a monolithic load-bearing system.
The structural properties :
1. Load-bearing Cross walls are of hollow blocks subsequently filled with concrete.
2. Non load-bearing external and partition walls are reinforced concrete panels with
insulation. They are made in whole spans between load-bearing walls. The outer panel is
composed of four layers, each having its own str~icturalpurpose.
3. The hollow reinforced concrete floor is composed of ribs spaced at intervals of 40 cm
each and lightweight hollow filling elements. Its total thickness ainounts to 20 cm.
4. The system adopts the 20 cm module dictating all spans of the elements. Three outer
and two inner spans are applied.
5. The floor-to-floor height is modular, and not the net height of the room.
6. Horizontal ducts for all necessary installations in the bathroom are built in in thepanel;
the vertical ducts are executed oii site.
7. The so-called 'Shunt' flues are used.
8. All the staircase components are prefabricated and simply assembled on site.
9. The windows are prefabricated in modular dimensions and of two sizes only. Their
assembly requires not more than 20 minutes.
10. The doors are mounted in steel frames built in in the workshop.
1 1. Thermal insulation of verticaland horizontal joints is provided. This method ofjointing
also allows for soine tolerances during assembly.
12. The system is improved by introducing an ever-increasing number of prefabricated
elements.
13. The execution of a building is divided into four stages. The first three stages together
(earthworks and foundations, carcassing, roof struct~ire)have the Same duration as the
fourth stage - building-craft works. It is easy to conclude that this last stage should be
removed from the building site and carried out in the workshop. Regarding speed of
execution, it has been stated that a block of 40 dwellings, 52 m2 each, requires about six
months.
14. Labour is not yet acc~istoinedto such methods of work and the ratio of skilled, semiskilled and non-skilled labour is 15 : 20 : 65.
15. The production of elements is organized in the workshop, i.e. in the concrete plant,
with an annual output of 30,000 m%f the various concrete building elements.
16. The systen-i shows considerable savings compared with traditional constructioii.
Figs. 1 A, B, C and Fig. 2 illustrate the PBM system of prefabrication.
Jiigomont of Zagreb is one of tl-ie first enterprises that have adopted f~il1prefabrication in
building.
Fig. 1
Fig. 2
-3&H
The first system, applied by the enterprise in 1955, when it started its building activity, is
based on the patented panel system of Mr. Helebrarit, C. E.
The system is composed of four basic elements, viz.:
1. wall panel,
2. anchorage,
3. caulking,
4. roof elemen t.
WALL PANEL
The wall panel is made as a sandwich panel and composed of thin reinforced concrete
frame and filling. The filling is composed of two layers of wood-fibre panels, each 3.5 cm
thick. These panels are the basis for exterilal and internal mortar and simultaneously serve
as a heat-insulating layer.
ANCHORAGE
The anchorage is the element serving in one-storey dwellings as the joint of the panel with
the roof structure.
CAULKING
The caulking is composed of two elements: internal, made of wood, and external, made of
asbestos-cement ; they are mutually tied by means of screws.
R O O F ELEMENT
The roof element is a wood structure composed of an arch and a lattice, and made of 2-cm
thick boards.
P A N E L SYSTEM JU-59
In the Course of the application of Mr. Helebrant's system a number of faults have been
revealed, so that a modified panel system under the title of JU-59 has since been adopted.
In structural respects the Same panel system is retained : the panels have been standardized,
the panel designing module is 1.0 m between joint centres. The thickness of wood-fibre
insulation has been reduced to 2.5 cm and a new method ofjointing panels has been adopted.
All other elements of the system are, except for some small modifications, the same as in
the first system, but a complete standardization of windows and doors made within modular
frames has been developed.
PANEL SYSTEM JU-60
A new systein of construction of flats and houses under the title of JU-60 is based on experience and aims at removing the faults revealed by former systems. It is kept in line with the
others as much as possible, with the existing resources and equipment of the enterprise
Jugomont.
The characteristics of the new JU-60 are as follows:
1. Elements are load-bearing and non load-bearing.
2. Finishing slabs are introduced, with provision for heat and sound insulation and
moisture exclusion.
3. Dry mounting of all non load-bearing elements.
4. Dry mounting of finishing slabs.
5. The system is statically determinate.
6. The basic panel is 1.0 m wide, 2.60 m high and 12 cm thick.
7. The dimensions of the basic elements of the system are 4.0 by 4.0 m.
8. All Spans have a length of 4.0 in.
9. Facade elements form an enclosure between the transverse load-bearing walls. This
allows various possibilities for architectural shaping.
10. The joints of the panels are the saine as in fornier Systems, but the Cross sections of the
joints are trapezium-shaped.
11. The number of different panels is reduced to a miniinuin.
12. The staircase is coniposed of three flights.
13. The inanufacture of the concrete load-bearing panel is much simpler.
14. Non load-bearing elements can be either prefabricated or traditionally made.
15. The finishing works are carried out in the following way :
(a) internal walls - 12 min Celotex and wall paper on concrete walls; (b) fagade elements building paper, 60 mm air insulation, 2 cni pressed reed, Celotex aiid wall paper; (C)ceiling Celotex over wood lattice; (d) floor finishes in the rooins of the dwellings are enameled
wood-fibre slabs; (e) floor finishes in the kitchen, bathrooms and toilets are asbestos-ceinent
tiles on floating subiloor; (f) external facade eleinents - 8 mm thick asbestos-cement sheathing.
According to this system the assembly is carried out as follows:
(i) Foundations of inonolitliic concrete.
(ii) Asseinbly of load-bearing elernents, placing of semi-prefabricated floor construction.
(iii) Asseinbly of stairs together with the erection of chiinneys.
(iv) The building is covered and the final assembly starts:
(a) non load-bearing elements,
(b) water installations and sewerage,
(C) electrical installations,
(d) finishing.
Figs. 3 , 4 and 5 illustrate tlie principle of construction according to the J U-60 system.
Fig. 3
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Fig. 4
Fig. 5
P R I M 0 R J E: A q9sten?o f pr¿fabrication ofapartntent houses al)p/ied bjl the enterl~rise'Primorje',
Rijeka
The characteristics of this system, which was applied in Rijeka for the construction of 380
dwellings during 1958, are as follows:
The houses consist of a basement and four storeys. The basement coilsists of a monolithic
reinforced concrete slab conforming to the terrain. The first floor and subsequent storeys
are prefabricated. The net height of the rooms amounts to 2.40 m, which is the minimum
height allowed by our regulations.
The buildings consist of load-bearing cross-walls with a net Span of 6.10 m and with
longitudinal bracings at the staircase. The distances between load-bearing cross-walls allow
the inclusion of a dwelling unit into each space thus obtained. Tlie load-bearing walls
(weight 400 kg/m" in this way form a good insulation between the dwellings. This at the
Same time allows a more flexible and economical arrangement of available space by the use
of lightweight partitions between rooms.
For the net span of 6.10 m the most economical type of floor construction has proved to be
a 32-cm high trough-shaped prestressed concrete slab structure.
All the walls are made of prefabricated elements of 1-1.5 ton each. The prefabricated
elements are made in one piece for the total height of a storey. We distinguish three kinds of
walls in the system concerned :
(a) Interna1 load-bearing walls 20 cm thick, made of 110-fines concrete.
(b) External non load-bearing walls made of 16 cm thick woodchip concrete with 4 cm
mortar rendering on the outer face.
(C) External load-bearing gable walls 25 cm thick, also made of no-fines concrete of an
appropriate strength.
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Fig. 6
Fig. 7
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The staircase is also prefabricated.
The dwellings are provided with water-supply installations and sewerage in a compact
sanitary block, as well as with electrical installations.
The floor finishes of auxiliary rooins are of terrazzo, and in the dwelling rooms of beechwood parquet.
The characteristic elements of the Primorje system are shown on Figs. 6 , 7 and 8.
Fig. 8
S L I D 1 N G S H U T T E R I N G : A sj7stetn applied ly! the builcling enterprise 'RAD', Belgrade
A characteristic of the building industry in Yugoslavia is the permanent lack of skilled
bricklayers. They are recruited with difficulty, since people prefer working in industry rather
than on a n Open building site with seasonal breaks. The shortage of skilled bricklayers was
one of the reasons for the decision of the building enterprise 'RAD' to use a specific type of
sliding shuttering mounted on structures of steel-tube scaffolding.
A set of six high buildings of this type with 300 dwellings has been constructed in Belgrade.
Experience has shown that the speed of erection of the carcassing is considerable; one
storey, including the floor construction, was erected in three days. However, the finishing
works were executed in a traditional way which slowed down construction and delayed the
completion of the project. New Prototypes of the system tend to increase and inlprove the
prefabrication of finishing works. It looks as tl-iough this system may compete successfully
with traditional construction. The principle of sliding shuttering and the projects carried out
are shown in Figs. 9, 10 and I 1.
T R U D B E N I K : Aparttl~enthouses constructecl hjv the sjsten? of the huilding enterprise 'Truclbenik'
Four apartment houses of 12 to 14 storeys each with 388 dwellings have been built on the
Same site by this principle.
The structural concept of the System is C haracterized by load-bearing transverse walls inade
of reinforced concrete. For the first four storeys these are 20 crn thick, and for the upper
storeys 15 cm thick. The floor constructions are 13 cm thick monolithic reinforced concrete
Fig. 9
slabs. The horizontal forces normal to the cross-walls are transmitted to structural wind
braces provided by the concrete wall panels. The walls are cast in accurately constructed
3 mm thick sheet-iiietal shuttering. A climbing tower crane placed in the building itself is
used for erecting and dismantling the shuttering, concreting of the walls and floor constructions, lifting all the prefabricated elenients of tlie building and carrying out all other
transport. The crane used is made in Yugoslavia. Its height is practically limitless because
it climbs with the building.
This system is unique in that it coniprises a special prefabricated slab enabling a quick and
efficient cladding of external walls between windows. This slab fulfils three functions, i.e.
Fig. 13
Fig. 14
lintel, a facing to ringbeams and a cladding between windows in successive storeys.
The system tends to promote a n ever-increasing assembly of inner components of buildings
and dwellings (prefabricated staircase. prefabricated railings, sanitary installations, etc.).
Figs. 12, 13 and 14 illustrate the principles of this method.
DURISOL SYSTEM
This internationally well-known system of light prefabrication, applied in the execution of
experimental houses in Belgrade, has shown considerable saving in labour, transport and
construction tiine. Compared with traditional methods of construction, this system is about
10- 15 per Cent cheaper. On the basis of these results the Municipality of Belgrade decided to
erect a block of apartment houses comprising 3,000 dwelling units. The exccution of this
work has confirmed the results obtained with the experimental houses, though it was not
possible to carry out a consequent standardization of the designs because of the prevailing
town planning and site conditions.
Figs. 15, 16 and 17 illustrate the applied Durisol system.
Fig. 15
Fig. 16
Fig. 17
2 E 2 E L J : Apartlllent hnuses
qf' ~ w e s t ~ . e . wroncrete
~tl
skeleton accortling to the sjlstoiz of Mr. i e z e l j ,
On the left bank of the Sava River near Belgrade big marshes have been draiiied and the
terrain lifted above the critical water level of the Danube and the Sava by means of sand.
The load-bearing capacity of the soil was not suficient for the gziieral town-planning
requirements which stip~ilatedthe construction of blocks of flats up to 14 storeys. Taking
account of these basic considerations, Mr. Zeielj used a prestressed concrete skeleton in order to reduce the weight of tlie building as much as possible.
The characteristics of this System are as follows: prestressed concrete colun~nsstretching
tlirough three storeys, and floor construction of a ribbed prestressed reinforced concrete
slab nieasuring 3.80 by 3.80 ni.
The systeiii is proving to be a speedy oiie. Prefabrication and the erection of elemeiits of
finishing works is carried out as niuch as possible on the site itself. As far as carcassing is
concerned, this has been coinpletely possible. A total of 3,000 dwelling units is now being
built. Unfortunately, no econoniic cornparisoti is available as yet, since the buildings are not
completed. The rapid Progress of this systeni proves tliat it is fully able to compete with
traditional construction, in spite of the introduction of expensive prestressed structural
elements which are not used in prefabricated structares in other countries.
However, it must be emphasized that Mr. Zeielj's system suits particularly buildings to be
erected on soils of low load-bearing capacity, and in these cases caii coiiip:te with other
Systems.
Figs. 18. 19 and 20 illustrate the systeni of Mr. Z e ~ e bC.
, E.
Fig. 18
Fig. 19
143
Fig. 20
Concluding this short contribution to the Second CIB Congress, we wish that it may serve
its purpose of mutual collaboration and excliange of experience of builders.
REFERENCE
Synlposium orr the Ind~rstrinlizcrtiorrin Horrsing, Belgrade, October 19-2 1 , 1960, Federal Chamber of Building,
Belgrade, 1960.