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PREFABRICATED BRIDGE GIRDERS – FROM DESIGN TO IMPLEMENTATION
Kálmán Koris – István Bódi – György Dévényi
To facilitate the practical application of European Standards (EN) in Hungary the Department of Structural Engineering at
the Budapest University of Technology and Economics was collaborating with the industrial partner SW Umwelttechnik Ltd. In
frames of this collaboration prefabricated, prestressed concrete bridge girders were also developed among other types of
prefabricated structural members. Beside the detailed numerical analysis of the girders according to EN, their durability
design was also performed using a probabilistic approach. In frames of the durability design, the probability of failure of the
prefabricated girders was analysed as a function of time, considering the effect of creep, shrinkage, relaxation, carbonation
induced corrosion and the deterioration of cross-sectional sizes due to environmental effects. Beside the design of standalone
girders, complete bridge superstructures consisting of the developed beams were also calculated to prove their applicability
according to EN. This article also provides a brief insight into the manufacturing process of the bridge girders, and some
examples to their application for highway construction projects are presented too.
Keywords: prefabrication, prestressed concrete, bridge girders, design, manufacturing, durability, Eurocode
1. INTRODUCTION
After the finalisation of European Standards (EN) in 2006 they were used parallel to the National Standard (MSZ) in Hungary.
The deadline for the usability of Hungarian National Standard expired on 31st March 2010 and after a nine-month grace period
only the European Standard can be used for the design of engineering structures. In the period before the introduction of EN –
prior to the current economic recession – SW Umwelttechnik Ltd. was working on the development of a new product line,
aiming the areas of bridge construction. To prepare for the practical application of EN, a cooperation was established between
the Department of Structural Engineering (Budapest University of Technology and Economics) and SW-Umwelttechnik Ltd.
to control existing prefabricated concrete members for the purposes of building construction, as well as to develop a range of
new prefabricated, prestressed concrete bridge girders by the exclusive use of EN (Bódi, Koris, 2006). The developed SHI
product line consists of 90 cm and 120 cm high bridge girders (Fig. 1). Considering 40-40 cm bearing lengths at the supports,
the SHI beams can be used for bridges with 10-32 m horizontal clearances. The prefabricated girders are cooperating with an
on-site reinforced concrete slab, allowing the construction of simply supported or continuous highway bridge structures.
Fig. 1: Cross-sections of beam types SHI90 and SHI120
16
52
90
38 9 17 9 17
50
2×Fp-55
5×3 Fp-100
5×3 Fp-100
50
70
18 73 15 14
120
15
2×Fp-55
2×3 Fp-100
4×3 Fp-100
6×3 Fp-100
2. DESIGN PROCESS
2.1. Design of the prefabricated girders according to EN
To be able to efficiently cover the typical span range for highway bridges in Hungary, two different cross-sections were
designed (Fig. 1). Beam type SHI90 is 90 cm high and its length changes between 10.80–26.80 meters, while the beam
SHI120 is 120 cm high with lengths between 16.80–32.80 meters. Exact shapes of the cross-sections were determined
considering the experiences of previous Hungarian road bridge girder types (Balázs, 1995; Koris, Salamak, 2007), as well
as the aspects of construction, transportation, erection, economy and durability.
The analysis of the individual beams started with the detailed calculation of the effective pre-stressing force,
considering the effect of creep, shrinkage and relaxation according to EN (Koris, 1998). The distribution of effective pre-
stressing force along the length of the beam was determined for each row of the cables (Fig. 2). Concrete stresses in the
top and bottom flange were also controlled after the release of the tendons (Fig. 3). The next step was the analysis of
ultimate limit states (ULS) including the bending and shear resistances of the girders (Koris, Bódi, Erdődi, 2005). These
types of beams are typically used for slab and beam bridges where the prefabricated girder is cooperating with a
monolithic reinforced concrete slab. Therefore, the ultimate bending moment was also determined and controlled for the
composite cross-section formed by the prefabricated beam and the on-site concrete slab (a 200 mm thick reinforced
concrete slab was considered in case of SHI90 beams, and a 250 mm thick one in case of SHI120 beams).
Beam SHI90-26,80
Prestressing stresses in the tendons
0
200
400
600
800
1000
1200
0 5 10 15 20 25
Distance from the end of the beam [m]
Stress [N/mm
2]
Initial prestressing stress - 1st row
Initial prestressing stress - 2nd row
Effective prestressing s tress - 1st row
Effective prestressing s tress - 2nd row
Beam SHI90-26,80
Concrete stress es in the top and bottom flange
after rele asing the tendons (initial stage)
-30
-25
-20
-15
-10
-5
0
5
0 5 10 15 20 25
Distance from the end of the beam [m]
Stress [N/mm
2]
Top flange Tensile strength
Bottom flange Compressive strength
Fig. 2: Initial and effective prestressing stresses Fig. 3: Concrete stresses in initial stage
Serviceability limit states (SLS) were also analysed, including the stress limitation, crack control and deflection control
of the girders. Expected deflection of the mid-span was calculated in different stages of construction; namely, after the
removal of the formwork, 28 days after concrete casting and in final stage when the beam already supports the weight of
the monolithic concrete deck, too. Fig. 4 illustrates the maximum deflections of the SHI120 beam of different lengths
28 days after concrete casting and in final stage (the number of the applied tendons is indicated for each case).
Fig. 4: Deflections of different SHI120 beams 28 days after concrete casting and in final stage
SHI120 girder - Final stage
-60
-40
-20
0
20
40
16 20 24 28 32
Length of gider [m]
Deflection [mm]
24+2
34+2
30+2
27+2
25+2
SHI120 girder - 28 days after concrete casting
0
20
40
60
80
16 20 24 28 32
Length of gider [m]
Deflection [mm]
24+2
34+2
30+2
27+2
25+2
Besides controlling the ultimate and serviceability limit states, we also analysed the local stresses at the ends of the girders
(Bódi, Koris, 2006). The exact distribution of transversal tensile stresses at the anchorage of the tendons, as well as the
necessary supplementary reinforcement were determined. Other local effects, like direct shear failure of the beam’s edge at the
support, and the punching resistance of the concrete at the bearings were also examined. Temporary stages (lifting and
transportation of the prefabricated beams) were investigated by checking the maximum concrete and steel stresses, as well as
the buckling resistance of the girders. Finally, the amount of reinforcement needed for the proper cooperation of prefabricated
beams and the monolithic concrete deck was determined.
After performing the above mentioned calculations according to EN, the detailed formwork and reinforcement plans were
prepared for each beam. The exact amount of concrete and reinforcement needed for the manufacturing of different beams
were determined (Table 1 summarises the data of SHI90 beams).
Table 1: Summary of data on the SHI90 beam type
[m
2
][m
3
][tons] [pcs] [kg/pcs] [kg/m
3
][pcs] [kg/pcs] [kg/m
3
][kg/pcs] [kg/m
3
]
SHI90-26,80 26.8 0.288 7.71 19.28 30 678.2 88.0 2 24.9 3.2 1545.8 200.5
SHI90-24,80 24.8 0.288 7.13 17.84 30 631.1 88.5 2 23.2 3.2 1443.3 202.3
SHI90-22,80 22.8 0.288 6.56 16.40 24 467.2 71.2 2 21.4 3.3 1343.4 204.8
SHI90-20,80 20.8 0.288 5.98 14.96 24 429.6 71.8 2 19.7 3.3 1240.6 207.3
SHI90-18,80 18.8 0.288 5.41 13.52 21 342.9 63.4 2 18.0 3.3 1140.7 210.9
SHI90-16,80 16.8 0.288 4.83 12.08 21 309.9 64.1 2 16.2 3.4 1038.2 214.8
SHI90-14,80 14.8 0.288 4.26 10.64 19 250.6 58.9 2 14.5 3.4 932.5 219.0
SHI90-12,80 12.8 0.288 3.68 9.21 19 220.7 59.9 2 12.8 3.5 855.3 232.3
SHI90-10,80 10.8 0.288 3.11 7.77 17 170.8 55.0 2 11.1 3.6 721.5 232.2
SteelbarsPrestressing tendons
Total
weight
Type of
beam Length
Area of
cross-
section
Concrete
volume Fp100 Fp55 B60.50
2.2. Analyses of bridge superstructures
The calculation of standalone bridge girders was implemented by the analyses of complete bridge superstructures consisting of
the developed beams to prove their applicability according to the EN. Altogether 8 different bridge superstructures covering
the total range of available beam lengths and types were controlled. Possible bridge cross-section configurations consisting of
SHI90 and SHI120 beams are displayed in Fig. 5. The internal forces of the sample bridge structures were numerically
determined by AxisVM civil engineering finite element software, considering the uniformly distributed (UDL) and
concentrated (TS) traffic loads defined for bridges by the EN.
Fig. 5: Sample cross-sections of bridge superstructures consisting of SHI90 and SHI120 beams
The design values of actions (bending moments and shear forces) obtained from the finite element calculations were compared
to the appropriate resistance values determined previously. According to this comparison, the examined bridge girders fully
meet the requirements of EN so they can be safely applied for the construction of highway bridges. Based on the results of
finite element analyses, the maximum applicable distance between the individual beams was calculated for each beam type
8.5055 55
11×0.75 = 8.25
m
15 17.5 35
80
12×SHI120-32,80
25
35 17.5 15
B
8.5065 65
6×1.50 = 9.00
m
10 4 26
80
7
×SH
I
90-10,80
25
26 4 10
A
Asphalt 10 cm
Water sealing 1 cm
Rc. bridge deck 20 cm
Shutter panel
A
Asphalt 10 cm
Water sealing 1 cm
Rc. bridge deck 25 cm
Shutter panel
B
separately. The applicable maximum of the unit gross load (excluding the self-weight of the beam) was also determined for
both ultimate and serviceability limit states. The independent control calculation of the SHI bridge girders and the sample
superstructures was performed by Pont-TERV Ltd. according to the Hungarian Highway Engineering Regulations (UT).
2.3. Durability design of the prefabricated girders
The importance of durability became an important aspect of the design process recently (Balázs, 2008). In order to provide
proper service life estimation for the developed bridge girders, the rheological changes of material properties and the decrease
of structural sizes due to environmental effects must be modelled, and these changes must be considered during the
determination of structural resistance. Rheological processes in reinforced and pre-stressed concrete are usually affected by the
environmental conditions, such as average temperature, ambient humidity and presence of aggressive agents, as well as by the
initial material properties of the structure. The design procedures of EN include the consideration of durability on a certain
level, but we decided to perform a more detailed durability design of the SHI girders. The implemented method is based on a
probabilistic approach, that is, the probability of failure of the examined beams was expressed at different ages of the examined
beams. To describe the long-term behaviour of the structure, we considered the creep and shrinkage of concrete, relaxation and
carbonation induced corrosion of steel bars and tendons, as well as the decrease of material properties and cross-sectional
dimensions during the analysis.
2.3.1. Basis of the applied probabilistic approach
The probability of failure of the SHI beams was calculated as a function of time, by means of varying load carrying capacity and
external loads, considering a failure due to bending (premature shear failure was always avoided by the application of appropriate
shear reinforcement). The first two stochastic parameters (mean value, standard deviation) were used to describe the distributions
of the structural resistance and the acting loads (Koris, 1996, 2007). Mean value and standard deviation of structural resistance
were calculated by stochastic finite element method (Lawrence, 1989), while stochastic parameters of load effect were considered
according to the referring literature (Mistéth, 2001).
Mean value of structural resistance was determined by finite element method (Bojtár, Gáspár, 2003) considering non-linear
behaviour of concrete and reinforcement. Mean values of geometrical sizes and material properties were used for the analysis. The
method of load increments was used and for each load increment, the chord stiffness matrix was evaluated. Failure of the structure
was specified by a damage indicator, consisting of the eigenvalue of stiffness matrix in case of structural damage and the
eigenvalue of current stiffness matrix at the given load level.
The scatter of structural resistance was evaluated from the scatter of the stiffness matrix (K). Assuming that K is a
function of an α random input variable, its variation (δK) can be approximately expressed by the first term of its Taylor’s series.
This approximation is reasonable if the variation of the stiffness matrix is less than about 15%. According to the results of the
calculations, this limitation does not apply to the analysed prefabricated beams. Using the above approximation, the covariance
matrix of structural resistance was expressed in the following form (Eibl, Schmidt-Hurtienne, 1996; Koris, 1996, 2004):
T
FF
T
FF K
K
uCu
K
KqqC −
ρ
−⋅
∂α
∂
⋅⋅αδ⋅⋅αδ⋅⋅
∂α
∂
⋅=δ⋅δ=
T
TT1
q
where δα includes the standard deviations of random input variables and Cρ is the correlation matrix. The correlation between
different finite elements was described by an exponentially decaying function of the distance between the elements and the
length of correlation. The standard deviation of structural resistance was obtained as square root of the diagonal elements in the
covariance matrix Cq. Using the above equation, the standard deviation of structural resistance was evaluated on structural
level. The applied stochastic finite element formulation was described by Koris, Bódi (2009).
2.3.2. Determination of the stochastic input parameters
Initial mean values and standard deviations of material properties were determined from material tests performed during
factory quality control. Concrete strength was obtained from uniaxial compression tests carried out on 150 mm cubes.
Laboratory tensile tests were carried out to determine material properties of reinforcement. Modulus of elasticity, strength and
ultimate strain of the steel bars and prestressing tendons were measured. The strength of concrete, steel bars and prestressing
tendons are the most important material properties to affect the structural resistance in ultimate limit state. The decrease of
mean values of material strengths was described by an exponentially decaying function (Koris, Bódi 2009). The loss of initial
prestressing stress (σp0 = 1200 N/mm2) was determined according to Eurocode 2, considering the effect of creep, shrinkage,
relaxation and the elapsed time since manufacture. The average stress loss in the tendons after 100 years was about 18% in
case of the analysed beams.
Mean values and standard deviations of cross-sectional sizes (height and width of the cross-section, effective depth of
steel bars and prestressing tendons) were determined from the results of measurements on manufactured SHI beams. Changes
of the mean values of geometrical sizes are usually insignificant in case of concrete structures, thus, constant mean value for
structural geometry was assumed during the calculation. Changes of the standard deviations of the given geometrical
parameters in time were considered by the Gauss-process (Mistéth, 2001).
Decrease of steel bar and tendon diameter due to carbonation induced corrosion was also considered. The carbonation
depth at a certain time after manufacture was calculated according to the fib bulletin 34 (2006). After the concrete cover is
completely carbonated, steel bars and tendons may begin to corrode. The relation between the diameter of rusted steel bar and
corrosion time under normal atmospheric conditions was considered by the following equation (Zhao, Fan, 2007):
() ()
∫
−∅=∅
t
corr dtti.t
0
002320
where t is the time of corrosion measured from the time of carbonation (tc = the time point where the carbonation depth is
equal to the concrete cover), Ø0 is the diameter of steel bars before corrosion, and icorr(t) represents current corrosion
density at time t.
2.3.3. Service life design of the SHI beams
The prefabricated SHI bridge girders were analysed by the introduced probabilistic design method. Results of the analyses
are presented in case of the SHI120 beam of three different lengths (20.8 m, 26.8 m and 32.8 m). During the calculations,
width and height of the cross section, effective height of steel bars and prestressing tendons as well as strength of concrete,
steel bars and tendons were considered as random quantities. Probability of failure was calculated in different points of
time. Selected times for the analysis were t=10, 25, 50, 75 and 100 years. According to our previous experiences (Koris,
Bódi, 2009), the value of relative ambient humidity has a significant influence on the aging process of the structure, so we
intended to use humidity values as realistic as possible for the analysis. A current place of application for the SHI beams is
the main road at Csepel Island, therefore, we evaluated the humidity level at this location. The humidity values measured at
a meteorological station close to the construction site were used to determine the monthly averages (Fig. 6). The average
relative humidity over the examined time period (4 years and 2 month) was about 70%, so this value was used for the
durability design of the SHI girders. Current values of input parameters were calculated by the computer software
PFEM2008 which was developed using the Matlab® software package. The bending capacity was evaluated for each
examined beam, considering the changes of input parameters due to the mentioned rheological processes (Koris, Bódi,
2009). The effect of elapsed time on the flexural behaviour of the cross-section is demonstrated by the corresponding
bending moment – curvature (M–κ) diagrams on Fig. 7.
40
50
60
70
80
90
2008.01
2008.05
2008.09
2009.01
2009.05
2009.09
2010.01
2010.05
2010.09
2011.01
2011.05
2011.09
2012.01
Examination pe rio d
Measured relative humidity RH [%]
Measured monthly average
Average of the examined period
Fig. 6: Change of the monthly average of relative humidity
over the examined time period
0
1000
2000
3000
4000
0
0,01
0,02
0,03
Curvature [1/m]
Bening moment [kN/m]
t=10 years
t=100 years
Fig. 7: Bending moment – curvature diagrams of the
SHI120-32.80 beam at different ages
The load carrying capacity of the girders was expressed by the maximum applicable load belonging to the appropriate
bending capacity. Fig. 8 illustrates the change of the mean value and standard deviation of the maximum applicable load in
case of different SHI120 beams. It can be stated that mean value of structural resistance slightly decreases, while its standard
deviation increases over time. The mean value of maximum applicable load is of course higher in case of shorter beams;
however, the relative standard deviation is larger in case of larger spans.
Using the stochastic parameters of the structural resistance and the load effect, the probability of failure was evaluated in
the selected points of time. Results of these calculations are summarised in Fig. 9. The different curves in the diagram refer to
SHI120 girders of different length. As we have expected, the probability of failure is increasing as time is passing by. The
effect of the beam length can also be observed by the comparison of the different SHI120 girders. Generally, the probability of
failure is higher in case of longer beams, but over time the difference between the examined members decreases. According to
EN the probability of failure cannot be larger than p=10-4 during the service life of the structure. The design service life of SHI
girders was 100 years, and the probability of failure at this time is lower than 10-4 for each analysed beam (see Fig. 9), so the
previous criteria is satisfied. The expected service life (ts) of the different SHI beams can be approximately calculated by linear
extrapolation of the given curves: ts,32.80 ≈ 101.5 years, ts,26.80 ≈ 108.5 years, ts,20.80 ≈ 117 years.
Summarising the results of the performed durability design, the analysed SHI girders slightly outperform the
requirements of the EN standard, even in case of the longest beams, so they can be safely used for the construction of highway
bridge superstructures.
1,00E-14
1,00E-13
1,00E-12
1,00E-11
1,00E-10
1,00E-09
1,00E-08
1,00E-07
1,00E-06
1,00E-05
1,00E-04
10 20 30 40 50 60 70 80 90 100
Time [ye ars]
Probability of failure
.
SHI120-20,80
SHI120-26,80
SHI120-32,80
Fig. 8: Change of the mean value and standard deviation of load carrying capacity in case of different SHI120 beams
3. MANUFACTURING OF THE PREFABRICATED GIRDERS
The bridge girders are manufactured using the ISO 9001:2000 Quality Management System, at the Alsózsolca (near Miskolc)
or Majosháza (near Budapest) sites of SW-Umwelttechnik Ltd. The geographical distance between these sites enables to
reduce the costs of transportation (which is relatively high due to the large size and weight of the girders) into different parts of
Hungary. Personal, technical and quality conditions for the appropriate prefabrication are given at both sites. There are 3×50 m
long prestressing beds available for the manufacturing SHI girders at Alsózsolca, and 3×100 m beds can be used at the
Majosháza site (Fig. 9 and Fig. 11). The utilised materials are subjected to strict quality control during prefabrication, and they
meet the requirements of the Hungarian Highway Engineering Regulations (UT). The concrete quality of the beams is C50/60 after
28 days. A picture of the manufactured SHI90 beams at Majosháza site is presented in Fig. 10.
Fig. 9: Reinforcement of the SHI90 beams Fig. 10: Manufactured SHI90 beams at Majosháza site
Fig. 11: Reinforcement detail of the SHI90 beams Fig. 12: Transportation of an SHI bridge girder
SHI 20,80
SHI 26,80
SHI 32,80
mean value standard deviation
20
30
40
50
60
70
80
10 20 30 40 50 60 70 80 90 100
Time [years]
Max. app licable load [kN/m]
The prefabricated bridge girders are transported from the factory to the construction site on public road, using appropriate
accompaniment. For the delivery of the girders, vehicles consisting of 13–44.5 meter long, three or four-axle, hydraulically
steered semi-trailers and coupled tractor units are used (Fig. 12). Transportation of the bridge girders is organised and
coordinated by SW-Umwelttechnik Ltd.
4. APPLICATION OF THE PREFABRICATED GIRDERS
Heavy-duty mobile crane can be used at the construction site for the lifting and positioning of the bridge girders. Beams must
be supported on rubber bearings, and they must be temporary fixed until the abutments and the concrete deck are constructed.
These works, completed with other activities connected to the application of the bridge girders (e.g. layout of bridge members,
construction of roadways and workspace needed for the transport and lifting of the beams) are performed by SW-
Umwelttechnik Ltd if required.
The SHI prefabricated bridge girders were used for the construction of the bypass road around the city of Komárom
(Fig. 12). The bypass road crosses the highway number 1, as well as an agricultural road and the Győr-Komárom railway line.
Both SHI90 and SHI120 girders were used for the construction, the total number of utilized beams was 73 (23 pieces of
SHI120-32,80 girders, 20 pieces of SHI90-16,80 girders and 30 pieces of SHI90-18,80 girders). Prefabrication of the beams
was done in the summer of 2009 for all three bridges, while on-site construction started at the beginning of 2010. The bridge
above the railway line is a continuous structure, the beams for the span above the railway tracks were positioned during the
night to avoid the disturbance of the railway traffic. The bridges above the highway number 1 and the agricultural road are
simply supported structures, the lifting and positioning of their bridge girders was done in the middle of 2010.
Fig. 12: Construction of the Komarom bypass road: lifting and positionig of the bridge girders
5. CONCLUSIONS
The Department of Structural Engineering at the Budapest University of Technology and Economics was collaborating with the
industrial partner SW-Umwelttechnik Ltd. to develop a new range of prefabricated concrete bridge girders using the EN standard.
Standalone prefabricated beams, as well as bridge superstructures consisting of the developed beams were designed and
controlled, and they proved to be safe against the appropriate traffic actions defined by EN.
A probabilistic approach was also used for the more accurate durability design of the bridge girders. The introduced
method is considering the creep and shrinkage of concrete, relaxation and carbonation induced corrosion of steel bars and
tendons, as well as the decrease of material properties and cross-sectional dimensions in time. Initial material properties and
geometrical sizes were determined by laboratory material tests and measurements on manufactured beams. The effect of
standard deviations of different input parameters (height and width of cross-section, effective depth of tendons, strength of
concrete and tendons) on the standard deviation of load carrying capacity were examined in case of different prefabricated
SHI120 bridge girders. The probability of failure of the analysed girders was calculated in selected time points, and the results
of this calculation were presented graphically. It was demonstrated that the probability of failure is increasing over time, and
longer girders will fail with higher probability, however the difference between girders of shorter and longer spans is
decreasing as time is passing by. Service life estimation of the presented girders was also performed and it turned out that they
outperform the requirements of the EN standard even in case of the longest beam. It means that they are fully suitable for the
construction of highway bridges.
Besides introducing the design of the bridge girders, their manufacturing, transportation and application was also
presented. According to the experiences, the SHI bridge girder family represents a product line meeting the latest requirements
and expectations.
6. REFERENCES
Balázs Gy. (1995), „Concrete and reinforced concrete II. – History of concrete and reinforced concrete civil engineering
structures“ (in Hungarian), Akadémiai kiadó, Budapest.
Balázs Gy. (2008), „Durability and methods for its improvement” (in Hungarian) Betonszerkezetek tartóssága (editors
Balázs Gy., Balázs L. Gy.), Műegyetemi Kiadó, Budapest, pp. 7-19.
Bojtár I., Gáspár Zs. (2003), „Finite Element Method for engineers” (in Hungarian) TERC Kft, Budapest.
Bódi I., Koris K. (2006), „Calculation of SHI prestressed bridge girders for administrative qualification process“ (in
Hungarian), Budapest University of Technology and Economics, Department of Structural Engineering, Budapest.
Eibl, J., Schmidt-Hurtienne, B. (1996), „Grundlagen für ein neues Sicherheitskonzept”, Bautechnik 72(8), pp. 501-506.
fib bulletin 34 (2006), „Model Code for Service Life Design”, Sprint-Digital-Druck, Stuttgart.
Koris K. (1996), „Safety of reinforced concrete beams subjected to combined stress” Proceedings of the 1st International PhD
Symposium (editor Balázs L. Gy.), Budapest, pp. 7-11.
Koris K. (1998), „Controlling of a prestressed concrete beam according to EC2” (in Hungarian) Beton évkönyv 1998/1999
(editor Szalai K.), Magyar Építőanyagipari Szövetség, Budapest, pp. 88-116.
Koris K. (2004), „Durability-design of reinforced concrete traffic infrastructure” Proceedings of the Second International
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Koris K., Bódi I., Erdődi L. (2005), „Parametric analyses of pre-cast concrete structural members“, Proceedings of the fib
Symposium Keep Concrete Attractive, Hungary, Vol. 1, pp. 717-722.
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Koris K. (2007), „Durability-design of pre-cast concrete members” Proceedings of the 3rd Central European Congress of
Concrete Engineering "Innovative materials and technologies for concrete structures" (editors Balázs L. Gy.,
Nehme S. G.), Visegrád, Hungary, pp. 407-412.
Koris K., Bódi I. (2009) „Probabilistic approach for the durability design of prefabricated concrete members” Concrete
Structures Vol. 10, pp. 41-48.
Koris K., Bódi I. (2009), „Long-term analysis of bending moment resistance on pre-cast concrete beams” Periodica
Polytechnika – Civil Engineering 53:(2), pp. 53-60.
Lawrence, M. (1989), „An Introduction to Reliability Methods” Computational Mechanics of Probabilistic and Reliability
Analysis (editors Belytschko, T., Liu, W. K.), Department of Mechanical Engineering, Northwestern University, Elmpress
International, Evanston.
Mistéth E. (2001), „Design theory” (in Hungarian) Akadémiai kiadó, Budapest.
Zhao D., Fan L. (2007), „Numerical analysis of carrying capacity deterioration and repair demand of existing reinforced
concrete bridge” Proceedings of the Fifth international conference on current and future trends in Bridge design,
construction and maintenance, Beijing, pp. 173-179.
Dr. Kálmán Koris (1970) civil engineer, graduated at the Budapest University of Technology and Economics, PhD,
Senior assistant professor at the Department of Structural Engineering, Budapest University of Technology and
Economics. Research fields: safety of reinforced concrete structures, analysis of prefabricated, prestressed concrete
structures, strengthening of structures. Member of the standardization subcommittee “NAD MSZ ENV 1992 Eurocode 2,
Design of concrete structures”. Member of the Hungarian Group of fib.
Dr. István Bódi (1954) civil engineer, post-graduate engineer in mathematics, PhD, Associate professor at the Department of
Structural Engineering, Budapest University of Technology and Economics. Research fields: Reconstruction and strengthening of
reinforced concrete and conventional structures, modelling of timber structure joints. Member of the ACI (American Concrete
Institute), the ACI Subcommitte#423 „Prestressed Concrete” and the Hungarian Chamber of Engineers. President of the
standardization committee Eurocode 5 - MSZ NAD (Timber Structures). Member of the Hungarian Group of fib. Member of the
„Schweizerische Arbeitgemeinschaft für das Holz”.
György Dévényi (1967) Graduated in 1988 at the Pollack Mihály Technical College, Building construction branch. 2003-2004
Expert engineer course in concrete technology at BME. 1988-1998 Private designer. 1988-1995 BVM factory at Budapest,
technical administrative, foreman and production rapporteur. 1995-2002 BVM Épelem Ltd., sales team leader, head of sales, chief
engineer, head of Csepel site (director of road construction division). 2002 BVM-MIX Ltd., executive director. 2002-2004 Strong
& Mibet Ltd., head of factory unit, sales manager. 2006-2008 Strongrocla Ltd., trade rapporteur. 2009- SW-Umwelttechnik Ltd.,
leader of building construction business.