IOP Conference Series: Materials Science and Engineering

PAPER • OPEN ACCESS Related content

- Water Wells Monitoring Using SCADA
Integration of Composite Structures in Modern Day System for Water Supply Network, Case
Study: Water Treatment Plant Urseni,
Architecture: Case Study of City Business Centre, Timis County, Romania
Cococeanu Adrian-Lucian, Cretan Ioana-
Alina, Cojocinescu Mihaela Ivona et al.
Timisoara, Romania
- Flexural stiffness of the composite steel
and fibre-reinforced concrete circular
To cite this article: Adina Vataman et al 2017 IOP Conf. Ser.: Mater. Sci. Eng. 245 082052 hollow section column
A Tretyakov, I Tkalenko, F Wald et al.

- Method of Analysis of the Topic of

Doctoral Thesis in the Field of Castings
Production. Case Study on the Situation in
View the article online for updates and enhancements. Romania
V F Soporan, V Samoil, T R Lehene et al.

This content was downloaded from IP address 106.208.137.65 on 12/09/2019 at 06:52

WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

Integration of Composite Structures in Modern Day

Architecture: Case Study of City Business Centre, Timisoara,
Romania

Adina Vataman 1, Vlad Gaivoronschi 1,2, Marius Mosoarca 1,3

1
Department of Steel Structures and Structural Mechanics, Politehnica University of
Timisoara, Ioan Curea Street, No. 1, Timisoara, Romania
2
Andreescu&Gaivoronschi, Piata Sf. Gheorghe No.4, Et. 2, Timisoara, Romania
3
H.I.Struct, Viilor Street, No. 33B, Timisoara, Romania

adina.vataman@upt.ro

Abstract. In current day structural design the use of composite steel-concrete structures has
become the norm; because of the advantages that each of these materials has to offer.
Composite structures also have the benefit of a faster execution at a lower cost, compared to
traditional structures. While the arguments in favour of designing composite structures are
well-known and appreciated by civil engineers; there remains a question of integrating these
structures in modern-day urban landscapes. Eastern European countries are welcoming a
blossoming of culture, arts, economy and industry, which unavoidably and necessarily will
lead to a change in urban landscapes. With an increasing amount of foreign companies opening
offices in these areas, the need for modern office solutions has arisen.
The current paper presents a case study of an office building complex situated in the western
part of Romania, in the city of Timişoara. The complex consists of 5 office buildings; all
designed in composite steel-concrete structure, an underground parking lot, multiple terraces
and adjacent promenade areas. Within the context of rapid growth and development of the city,
the City Business Centre has offered high quality office spaces in the heart of the city, while
considering the needs of the community. A very important aspect in the successful completion
of the project was the efficient and professional collaboration between the separate project
teams, between the owner, represented by the project management team, the architect, the
structural designer and the building company. The successful joining of seismic structural
solutions with modern architectural aesthetics has led to a dynamic, vibrant environment,
making the City Business Centre the core of the region’s business life, at the same time
redefining Timisoara’s architectural landscape. A testimony to the success of the project was
the Civil Engineering Structural Designers Associations’ (AICPS) 3rd Prize awarded for great
performance and quality in structural design. The project was also awarded a „Green Building
of the Year” award by the Romanian Green Building Council and also the „Office
Development of the Year” in South-Eastern Europe awarded at the Real Estate Awards by an
international jury of renowned real estate developers, consulting firms and investment banks.
The project was also selected by the European Architects’ Council to represent Romania in a
Sustainable Architecture Exhibition at the European Parliament in Brussels.

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution
of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Published under licence by IOP Publishing Ltd 1
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

1. Introduction
When talking of composite structures one usually refers to the use of at least two different structural
construction materials, as for example steel, reinforced concrete, wood, aluminium etc. The current
article will focus mainly on steel - reinforced concrete composite structures.

The use of composite steel-concrete elements in a structure has been around for many decades and
continues to be more and more present around the world, as these structures have proven themselves
to be quite efficient both structurally and economically. The material properties of reinforced concrete
and steel are well known, with the concrete having a good compressive resistance and the steel a good
tensile resistance. Combined, the two materials can assure a high resistance capacity, which also leads
to slender elements, that are more economical and at the same time aesthetically pleasing.

The generally used composite structural elements include composite beams, which represent steel
beams connected to the reinforced concrete slab by means of shear connectors; composite slabs, which
are reinforced concrete slabs that have been poured into steel profiled sheeting; composite columns,
which include a steel profile completely or partially encased in concrete.

While in some countries the use of these structures is prevalent, in others, mainly those from the
eastern part of the continent, especially former communist countries, are only now discovering the
benefits of such structures. The integration of new architectural currents and structural solutions into
an existing urban landscape can prove a challenge, which sometimes when faced with professionalism
and a good team of specialists, can also lead to a success.

2. Case-study: City Business Centre, Timisoara, Romania

2.1. Geographical and social background
A lot of eastern European countries are currently welcoming a new age of development, reflected in
everything from everyday life, to art, to the different industries. In terms of the construction industry
this development can be observed in new building being erected, often times contrasting with existing
historical or communist era buildings.

Romania, which is located in central-eastern Europe, at a crossroads between the West and the
East, presents a similar situation. Since most of the country was occupied for decades or even
centuries, (notably being the austrian-hungarian occupation), most cities are filled with historical
buildings from that time. Being subjected to a communist regime for approximately 40 years, the
country was also filled with “monuments” of communist architecture.

Timisoara (Figure 1) is the largest city in the western part of Romania and third largest in the
country. It represents an important industrial, commercial, medical and educational center. It was part
of the Kingdom of Hungary in the 14th to 16th century, was under ottoman occupation for 150 years
and also part of the habsburgic and austrian-hungarian empire for two centuries. Lastly in 1918
Timisoara finally became a part of Romania. And a very important part, since it is the place where in
1989 the spark appeared that ignited the Romanian people’s revolution, which put an end to
communism in the whole country. After such a troubled past, Timisoara was left with a very
multicultural background, a melting pot of different cultures, traditions, languages and last but not
least, different urban landscapes.

2
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

Figure 1. Geographical location of the city of Timisoara, Romania

Timisoara has the highest number of historical monument buildings in Romania (over 14.000), but
sadly these beautiful baroque, art-nouveau and secession style buildings are overshadowed by
“communist” buildings, erected in all the historical areas, including the city center. Most of these
buildings are large prefabricated concrete panel buildings for collective housing. But since during
communism the country underwent a wave of industrialization, the cities were also filled with
factories. Timisoara was no exception. One of these buildings was represented by the “Bega” clothing
company, located very close to the center of the city. Though a state owned company (since 1959),
after the fall of communism it was privatized in 1994 and became a family business - ModaTim
(Figure 2). In 2009 the clothing company relocated its facilities outside of the city limits, thus
presenting an incredible real estate opportunity for the remaining plot of land.

a)

b)

3
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

c)
Figure 2. a-c) The old buildings of the ModaTim clothing company - different views
Under these circumstances in 2006 a building project was started, consisting of 5 class A office
building, the first of their kind in Timisoara. The project, quite impressive compared to other new
constructions at the time, was to provide the city and its ultra-central areas with much needed quality
office spaces, conference rooms, art gallery, commercial spaces, underground parking etc. While also
rehabilitating the adjacent areas, the project has managed to add a special flavour to the city’s business
life.
2.2. Architectural Design
The City Business Centre building complex was finalized recently on the edge of the historical center
of the city. It has successfully replaced several textile industry buildings erected in the seventies over
the pre-existing 18th century Vauban type defense walls foundations. The area was part of the
communist industrial framework of Timisoara, which started with the construction of the Textile
Factory and the Civil Engineering High School and continued after the fall of communism (1990) with
the construction of different public and private buildings, all developed in the absence of a coherent
urban planning system or strategy.

Figure 3. Volumetric view of the area and the City Business Centre ensemble
The main objective of the City Business Centre ensemble was the development of public galleries
and plaza, semi-public spaces, halls, foyers, conference center, commercial spaces and, at upper levels,
a class office, all tied together in a compact pattern with the purpose of representing the first step of an
urban regeneration project. The ensemble presents common elements for all five buildings with
superimposed layers, with green terraces over the mezzanine and 5th floor, intermittent loggias with
ceramic louvers creating a transparent inner space, and the unifying, dominant element – the
mezzanine level, prevailing over the entire composition. A curtain wall type glass façade represents
the outer skin of the buildings contrasting with the ceramic louvers and green terraces [1].

4
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

A pedestrian gallery between the northern and southern poles of the urban plaza generates a gate
towards the first two buildings from the east and integrates the two atriums from the west. The
longitudinal gallery following the site’s north-south axis becomes the backbone of an ensemble where
pedestrian passages host lively landscaped spaces, urban art and glass funnels. The south corner
boundary is represented by the urban plaza, which became a generous amphitheatre, due to the
existing level difference. Although the initial project featured an emblematic work of art in this
location, an archaeological surprise offered a whole new perspective and purpose for this particular
space.

2.3. Archaeological findings

During foundations work, defense walls including a XVIII century sluice used in the defense system
around the bastion emerged while digging and construction on the site halted in order for the history
museums archaeology team to come and assess the finding.

Historically, the city of Timisoara played an important defensive role during the Ottoman Empire
and the Austrian- Hungarian Empire occupations. Surrounding swamps and moats made the fortress of
the city difficult to be conquered. After the Austrian conquering of the city in 1716 new defense walls
were built and hydro-technical systems for regulating the water levels of the moat within and
surrounding the fortress. Because of the low bearing capacity of local soils all the new buildings were
constructed on top of wooden pile foundation.

After careful consideration of the unique discovery of the historical hydro-technical system, the
decision was made to disassemble and reassemble everything within the newly constructed urban
plaza. While keeping the original orientation, everything (approximately 400sqm) was translated by 30
meters to the east and lifted at a height of approximately 5m. An open-air museum was conceived,
with exhibition panels (that present information about the fortress defense walls and water monitoring
system of the sluice), suspended viewing terrace and night time architectural lighting system. The
display of the architectural findings demonstrates the benefits of urban regeneration, the importance of
the collaboration between engineers, architects, archaeologists and local authorities and can engage
people in the rescue and valorisation of historic heritage sites and buildings.

This particular example is the proper symbol for a technological innovative city, while enhancing
the atmosphere of the pedestrian gallery and plaza - a surprise exhibition dedicated to Timisoara’s
modern history [2].

Figure 4. Archaeological discovery and relocation to the out-door museum in the urban plaza

5
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

2.4. Structural Design

The structural design objective was to create an 10 storey office building (Figure 5), consisting of
underground parking level, ground floor, mezzanine, 5 storeys, penthouse and utility terrace level,
while considering loading from permanent and live loads, snow and wind loads and seismic action.

Timisoara is located in the Banat region of Romania, its second most important seismic region with
characteristic low depth earthquakes. This fact is very important in the structural design of buildings in
the region and must be taken into consideration during the design phase [3]. Composite steel-concrete
structures have an adequate behaviour in the case of seismic action and are well suited in this case.
The importance class of the buildings is class III and seismic zone D. Design values for Timisoara’s
seismic zone were considered to be ag=0.16g and Tc=0.7s [4].

Figure 5. Steel-composite structure - numerical design model

The structural solution best fitted for the design of the structure consisted of composite steel-
concrete frames on two directions, transversal and longitudinal, with a reinforced concrete vertical
diaphragms central for the central tube, housing two staircases and the elevator shaft (3 elevators). The
frames included both composite beams and composite columns.

Composite steel-concrete structures have the benefit of quick on site erecting, leading to a lot of
storeys being built in a short period of time compared to classic reinforced concrete structures which
need extra time for the concrete to reach its complete resistance (after 28 days).

The structural analysis was performed on the 3D numerical model considering serviceability limit
state conditions (SLS) and ultimate limit state conditions (ULS), as indicated in Eurocode 4 [5]. The
relative displacements for each level were calculated and all within normative limits, with the highest
value reached by the mezzanine floor of 11 mm (maximum admissible 20mm). Afterwards stress
diagrams were used in order to establish the design values of the stresses, for axial force, bending
moment and shear force.

6
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

Figure 6. Stress diagrams – Bending moment M, Axial Force N, Shear force T

For the beams two different profile sections resulted (Figure 6 and Figure 7), an HEA450 profile
and a more slender IPE450 profile, using S235 steel grade. Since the beams are realized in composite
solution, steel Nelson shear stud connectors were used to assure the composite behaviour of the
beams. They were positioned in two rows along the whole length of the beam.

Figure 7. Composite HEA450 beam details: Cross-section; Beam-column connection detail.

The initial beam profiles were used in order to obtain castellated beams with circular openings
(Figure 9). All of the heating, ventilation, air conditioning (HVAC), electrical and fire-prevention
equipment was installed through the beam web openings. By reducing the necessary height for
installation of the different types of equipment in the ceiling an additional level could be added to the
structure, while still maintaining the limit for medium height buildings as prevalent in the area.

Figure 8. Composite IPE450 beam details: Cross-section; Beam-column connection detail.

7
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

The column analysis for compression, bending, shear and combined axial force-bending moment
calculation resulted in a HEA300 steel S235 profile, encased in a concrete rectangular cross section of
45x65cm for the columns on the perimeter of the building and a HEA500 steel S355 profile encased in
an almost rectangular concrete section with 65x65cm dimensions, as seen in Figure 8 and Figure 10.

Figure 9. Column cross-section: Left- Exterior perimeter column; Right - Central column.
On both sides of the web of the column profiles studded shear connectors were applied in one row
along the length of the column in order to assure the complete interaction between the steel profiles
and the reinforced concrete. For all the concrete elements a concrete class of C20/25 was used.

Figure 10. Castellated beams during construction

Figure 11. Composite columns during construction

8
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

3. Discussions
3.1. Advantages of composite steel-concrete structures
The advantages of composite steel-concrete structures range from structural, to financial, even
logistical. From a structural point of view these types of structures are quite appropriate for seismic
areas, combining the resistances of both steel and reinforced concrete, leading to smaller cross sections
(less material means less costs), more efficient use of space, and more flexibility in design. The
castellated beams allow placing equipment through them, leading to a more effective use of floor
height. The time efficiency of erecting such a structure is another important advantage, which also
makes composite structures an economically competitive solution.

3.2. Conclusions
Even though the position is very close to the city centre, the presented area used to be very
unremarkable, consisting mostly of industrial buildings and brown fields. The new office buildings
project has achieved its first goal of obtaining an efficient ensemble as speculative investment.
Another goal of the project was to connect main pedestrian routes transforming the ground floor and
the mezzanine in public and semi-public spaces (Figures 11, 12, 13).

Figure 12. Aerial view of the City Business Centre ensemble

Figure 13. View of the pedestrian zone between the buildings

9
WMCAUS IOP Publishing
IOP Conf. Series: Materials Science and Engineering 245 (2017) 082052 doi:10.1088/1757-899X/245/8/082052
1234567890

Figure 14. Lobby areas – Building C and E

The use of modern composite steel-concrete structural solutions allows for a greater flexibility in
architectural design, with more spacious buildings, suited for a whole range of destinations, from
offices, to art galleries, conference rooms and commercial spaces. The structural elements do not
inhibit the aesthetic of the building, but enhance the possibilities of different architectural elements
and design solutions, while still ensuring the necessary structural resistance.

Conceived as a gate to the city, the City Business Centre ensemble was expected to regenerate the
whole west part of the city centre. During initial discussions and design, it was established that the
urban plaza will represent an optimal out-door exhibition space to feature art pieces and locally found
archaeological artefacts, [2]. The successful joining of seismic structural solutions with modern
architectural aesthetics has led to a dynamic, vibrant environment, making the City Business Centre
the core of the region’s business life, at the same time redefining Timisoara’s architectural landscape.

Acknowledgment
This work was partially supported by the strategic grant POSDRU/159/1.5/S/137516 of the Ministry
of National Education of Romania, co-financed by the European Social Fund – Investing in People,
within the Sectorial Operational Programme Human Resources Development 2007-2013. The authors
would like to acknowledge the assistance and support of HIStruct structural design company and
Andreescu & Gaivoronschi associated Architects Company.

References
[1] I. Andreescu, V. Gaivoronschi, “City Business Centre Final Ensemble (C, D, E Buildings and
public spaces)”, World Architecture Festival – WAF, 2016.
[2] M. Mosoarca, V. Gaivoronschi, I. Andreescu, V. Stoian, “Urban valorization of a military
heritage building. Case study: City business center, Timisoara”, 10th International
Conference on Structural Analysis of Historical Constructions - SAHC 2016, Leuven;
Belgium, pp.1627-1634, 2016.
[3] C. Costa, L.F. Costa-Neves, L.R.O. de Lima, J.G.S. da Silva, “Towards an Optimized Layout of
Steel and Concrete Composite Building Structures”, Proceedings of the 10th International
Conference on Computational Structure Technology, Spain, 2010.
[4] P100-1: Seismic design code – Design regulations for buildings, 2013.
[5] European Committee for Standardization CEN, EN 1994-1 Eurocode 4: Design of composite
steel and concrete structures, Brussels, 2006.

10