m - ACES

1
Prestressed composite box girder bridges
with corrugated webs
A critical comparison with flat steel webs
Ing. Gabriele Bertagnoli
Politecnico di Torino

2
Some examples of the use of corrugated
webs in bridges
(and other civil structures)

• Pont de la Corniche, France
3

• Himi Yuma Bridge, Japan
4

• Ginzan-Miyuki Bridge, Japan
5

• Hontani Bridge, Japan
6

• Long span building structures
(by “Zeman & Co”)
7

Some examples of the use of flat steel
webs in composite steel-concrete bridges
8

Verrieres bridge – France
9

Roccaprebalza Viaduct : Parma – La Spezia Highway - Italy
10

Gassino bridge – Torino - Italy
11

Gassino bridge – Torino - Italy
12

Some theory stuff
13

14
Bending behaviour of corrugated webs
As the web is corrugated, it has very little ability to sustain longitudinal
stresses. Conventionally the contribution of the web to the ultimate
bending capacity of a beam with corrugated web is assumed
negligible, and the ultimate bending capacity is calculated using the
plastic modulus of the flanges.
Elgaaly (1997) carried out experimental and analytical studies to verify
if the web can contribute to the bending capacity of the whole girder.
Dimentions
in cm

15
Bending behaviour of corrugated webs
In order to verify if the web can contribute to the bending capacity of
the whole girder, the failure moment is compared with the bending
moment corresponding to the yielding of the flanges. It was found
that the web contribution could be neglected.
M f ≃ M y,f M y,w ≃ 0
y,f
The bending capacity of the whole girder is affected by many
parameters. The following factors were analyzed:
a. ratio between the flange and web thickness;
b. ratio between the flange and web yield stresses;
c. corrugation configurations.
The stresses in the web due to bending are equal to zero except for
small regions very close to the flanges where the web is restrained.

16
Shear behaviour of corrugated webs
FAILURE
MODES
Local
buckling
Zonal
buckling
Global
buckling

17
Shear behaviour of corrugated webs
FAILURE
MODES
Local
buckling
Zonal
buckling
Global
buckling

18
Shear behaviour of corrugated webs
FAILURE
MODES
Local
buckling
Zonal
buckling
Global
buckling
θ
6
60° 60° 45° 30°

1/d
19
Shear behaviour of corrugated webs
FAILURE
MODES
Local
buckling
Zonal
buckling
Global
buckling
n=L TOT /a

Shear behaviour of corrugated webs
20

21
Shear behaviour of corrugated webs
Strength of corrugated webs
subjected to shear:
- Local buckling (similar
expression of the local buckling
formula for normal plate girder
developed by Timoshenko and
Gere)
2
2
E π E ⎛ a ⎞
τ
cr,L
= kl
⋅
2 ⎜ ⎟
12 ( 1 − ν
) ⎝ w
⎠
- Global buckling (calculated
from the orthotropic-plate
buckling theory)
τ
E
cr,G
1 3 4
y
⋅D
4
x
2
D
= k
g
⋅
w ⋅h
- The shear yield stress τ y is
defined by the Huber-Von
Mises-Hencky yield criterion
f
y
τ
y
= ≈ 0 58
3
. f
INTERACTIVE BUCKLING
STRENGTH
y

22
LIVE LOADS :
ELASTIC ANALYSIS
DEAD LOAD + CREEP + SHRINKAGE + PRESTRESSING +
CONSTRUCTION PHASES:
VISCOELASTIC ANALYSIS
• The structure is not homogeneous from the rheological point of view:
viscoelasticity theorems CAN NOT be used
• step by step analysis with detailed time history:
ε ( t
c
k
t
k
) = ∫ J ( t,
τ ) dσ
( τ ) + ε
cs
( tk
) ≈
t0
=
i
k
∑
1
⎧
⎨
⎩
1
2
[ σ ( t ) −σ
( t )] ⋅ ⋅[ J ( t , t ) + J ( t , t )] ε ( t )
c
i
c
⎫
⎬
⎭
i− 1
k i k i−1
+
cs
k

23
Creep and relaxation functions used in phased
analysis
t
+ ∫
0
J ( t,
τ ) dσ
( τ
t
ε ( t)
= σ ⋅ J ( t,
t0)
σ ( t)
= ε ⋅ R(
t,
t0
t
+ ∫
0
) R(
t,
τ ) dε
( τ
t
0
0
)
)
J ( t,
t
0
)
=
1
ϕ
(
t
,
t
+
E(
t ) E
0
28
0
)
ϕ( t,
t0)
≥
0
R( t,
t0)
= E(
t0)
+ E28
⋅ ρ(
t,
t0)
ρ(
t,
t0)
≤
0

Comparison of flat webs solution and
corrugated webs solution on the same
“testing” bridge
24

Construction procedure common to both
flat and corrugated webs solutions
25

26
Gassino bridge reduced to 3 hammers scheme
50m
92m 92m 50m
Concrete top slab with
bonded prestressing
Soletta superiore
Steel
webs
Trave in acciaio
Predalle prefabbricata
Precast slab
used as
scaffolding
Soletta inferiore
Concrete
bottom slab

27
Position
Continuity
support
Midspan and
abutments
Deck depth
[m]
Depth/Span
length L/h
4 23
2 46

28
Single hammer construction
phases
Hammers construction
phases

Phase 1 - Positioning of steel box pier segment
(formwork for concrete diaphragm casting)
29

30
Phase 2 - Webs assembling by bolts and adjustment/stiffening by
temporary ties
Phase 3 – Slabs
Phase 3 – Slabs
concreting

31
Phase 4 – Internal prestressing
28 tendons: 6 for each segment apart from segment 1 which has 2
Strand cross Nominal Duct
N°of strands
section area diameter
15 139 mm 2 2085 mm 2 90 mm

33
Phase 4 – Internal prestressing
Layout of the
connection
reinforcement
between precast
anchorage blocks and
upper slab.

34
Phase 5
Repetition of previous
operations working in
parallel on several piers
Phase 6 – Alignment of bolted joint on webs between two segments

Phase 7 – External prestressing: 10 tendons with 27 strands in
main spans and 22 strands in lateral ones
35

Phase 7 – External
prestressing
36

Pay attention to the geometrical interferences between
external tendons and stiffeners
37

38
Transversal truss stiffeners
detail.
Longitudinal spacing = 3m
The shape of plenty of them
is modified to avoid external
tendons geometrical
interferences.
(See arrows in the picture
(See arrows in the picture
beside and in the previous
slide)

Construction time scheduling common to
both flat and corrugated webs solutions
39

40
Hammers 1 and 3
Time steps
Elements activation
Loads activation
Day Time [d] Phase Segment Side Set Segment side Load
Monday 1 1 0 Web+TS+BS
Wednesday 3 1 0 Web+TS+BS
Thursday 46 2 1 Right Web 1 Right Web
Friday 47 3 1 Left Web 1 Left Web
Saturday 48 3 1 Right BS
Monday 50 3 1 Left BS
Tuesday 51 4 1 Right BS
Wednesday 52 5 1 Left BS
Thursday 53 5 1 Right TS
Friday 54 5 1 Left TS
Saturday 55 6 1 Right TS
Monday 57 7 1 Left TS 1 Prestress
Tuesday 58 8 2 Right Web 2 Right Web
Wednesday 59 9 2 Left Web 2 Left Web
Thursday 60 9 2 Right BS
Friday 61 9 2 Left BS
Saturday 62 10 2 Right BS
Monday 64 11 2 Left BS
Tuesday 65 11 2 Right TS

41
Evolution of internal actions during
construction and service life of
FLAT WEB SOLUTION

42
Bending moment diagrams during hammer construction phases
3,00E+07
Bending moment [Nm]
Momenti [Nm]
2,00E+07
1,00E+07
End of
segment 1
Fine concio 1
0,00E+00
40 45 50 55 60 65 70 75 80 85
-1,00E+07
-2,00E+07
-3,00E+07
Longitudinal Coordinata axis [m] [m]

43
Bending moment diagrams during hammer construction phases
3,00E+07
Bending moment [Nm]
Momenti [Nm]
2,00E+07
End of
1,00E+07
Fine segment concio 1
0,00E+00
40 45 50 55 60 65 70 75 80 85
-1,00E+07
-2,00E+07
Prestressing
of Tiro tendons cavi 1-21
and 2
-3,00E+07
Longitudinal Coordinata axis [m] [m]

44
Bending moment diagrams during hammer construction phases
3,00E+07
Bending moment [Nm]
Momenti [Nm]
2,00E+07
Fine segment concio 2
End of
1,00E+07
Fine segment concio 1
0,00E+00
40 45 50 55 60 65 70 75 80 85
-1,00E+07
-2,00E+07
Prestressing
of Tiro tendons cavi 1-21
and 2
End of
-3,00E+07
Longitudinal Coordinata axis [m] [m]

45
Bending moment diagrams during hammer construction phases
3,00E+07
Bending moment [Nm]
Momenti [Nm]
2,00E+07
1,00E+07
0,00E+00
40 45 50 55 60 65 70 75 80 85
-1,00E+07
-2,00E+07
-3,00E+07
End of
segment 1
Fine concio 1
Prestressing
of Tiro tendons cavi 1-21
and 2
Longitudinal Coordinata axis [m] [m]
End of
segment 2
Fine concio 2
Prestressing
Tiro cavi 3-5
of tendons 3,
4, 5

46
Bending moment diagrams during hammer construction phases
6,00E+07
5,00E+07
Bending moment [Nm]
Momenti [Nm]
4,00E+07
3,00E+07
2,00E+07
1,00E+07
0,00E+00
20 30 40 50 60 70 80 90 100 110
-1,00E+07
-2,00E+07
End of
Fine concio segment 3
-3,00E+07
Longitudinal Coordinata axis [m] [m]

47
Bending moment diagrams during hammer construction phases
6,00E+07
5,00E+07
Bending moment [Nm]
Momenti [Nm]
4,00E+07
3,00E+07
End of
Fine concio 2,00E+07
segment 3
1,00E+07
0,00E+00
20 30 40 50 60 70 80 90 100 110
-1,00E+07
-2,00E+07
-3,00E+07
Longitudinal Coordinata axis [m] [m]
Prestressing
of tendons 6,
7, 8
Tiro cavi 6-8

48
Bending moment diagrams during hammer construction phases
6,00E+07
5,00E+07
Bending moment [Nm]
Momenti [Nm]
4,00E+07
End of
3,00E+07
End of
Fine segment concio 4
Fine concio 2,00E+07
segment 3
1,00E+07
0,00E+00
20 30 40 50 60 70 80 90 100 110
-1,00E+07
-2,00E+07
-3,00E+07
Longitudinal Coordinata axis [m] [m]
Prestressing
of tendons 6,
7, 8
Tiro cavi 6-8

49
Bending moment diagrams during hammer construction phases
6,00E+07
5,00E+07
Momenti [Nm]
4,00E+07
3,00E+07
2,00E+07
1,00E+07
0,00E+00
20 30 40 50 60 70 80 90 100 110
-1,00E+07
-2,00E+07
-3,00E+07
Prestressing
of tendons 9,
10, 11
Tiro cavi 9-11
End of
segment 3
Fine concio 3
Longitudinal axis [m]
Coordinata [m]
End of
segment 4
Fine concio 4
Prestressing
of tendons 6,
7, 8
Tiro cavi 6-8

50
Bending moment diagrams during hammer construction phases
9,00E+07
8,00E+07
Bending moment [Nm]
Momenti [Nm]
7,00E+07
6,00E+07
5,00E+07
4,00E+07
3,00E+07
2,00E+07
1,00E+07
End of
Fine segment concio 5
0,00E+00
10 30 50 70 90 110
-1,00E+07
Longitudinal Coordinata axis [m] [m]

51
Bending moment diagrams during hammer construction phases
9,00E+07
8,00E+07
Bending moment [Nm]
Momenti [Nm]
7,00E+07
6,00E+07
5,00E+07
4,00E+07
3,00E+07
2,00E+07
1,00E+07
End of
Fine segment concio 5
Tiro Prestressing cavi 12-14
of tendons
12, 13, 14
0,00E+00
10 30 50 70 90 110
-1,00E+07
Longitudinal Coordinata axis [m] [m]

52
Bending moment diagrams during hammer construction phases
7,00E+07
6,00E+07
Bending moment [Nm]
Momenti [Nm]
5,00E+07
4,00E+07
3,00E+07
2,00E+07
1,00E+07
Grouting of
all internal
tendons
Sigillatura cavi
interni
0,00E+00
10 30 50 70 90 110
-1,00E+07
Longitudinal Coordinata axis [m] [m]

53
Bending moment diagrams: external prestressing
introduction on lateral spans
7,00E+07
6,00E+07
Bending moment [Nm]
Momenti [Nm]
5,00E+07
4,00E+07
3,00E+07
2,00E+07
1,00E+07
50% of lateral
spans
Precompressione
campate
prestressing
laterali (50%)
Grouting of
all internal
tendons
Sigillatura cavi
interni
0,00E+00
10 30 50 70 90 110
-1,00E+07
Longitudinal Coordinata axis [m] [m]

54
Bending moment diagrams: end of construction of central
hammer
8,00E+07
6,00E+07
Bending moment [Nm]
Momenti [Nm]
4,00E+07
2,00E+07
0,00E+00
-2,00E+07
-4,00E+07
-6,00E+07
Fine stampella
End of
2
construction
of hammer 2
0 50 100 150 200 250 300
-8,00E+07
Longitudinal Coordinata axis [m] [m]

55
Bending moment diagrams: introduction of central spans
external prestressing
8,00E+07
6,00E+07
Bending moment [Nm]
Momenti [Nm]
4,00E+07
2,00E+07
0,00E+00
-2,00E+07
-4,00E+07
-6,00E+07
Fine stampella 2
0 50 100 150 200 250 300
50% of central
span prestressing
Precompressione
campate centrali (50%)
End of
construction
of hammer 2
-8,00E+07
Longitudinal Coordinata axis [m] [m]

56
Bending moment diagrams: permanent loads introduction
8,00E+07
Bending moment [Nm]
Momenti [Nm]
6,00E+07
4,00E+07
2,00E+07
0,00E+00
-2,00E+07
-4,00E+07
-6,00E+07
Perm. Permanent portati
loads
0 50 100 150 200 250 300
-8,00E+07
Longitudinal Coordinata axis [m] [m]

57
Bending moment diagrams: introduction of 2 nd 50% of
external prestressing
8,00E+07
Bending moment [Nm]
Momenti [Nm]
6,00E+07
4,00E+07
2,00E+07
0,00E+00
-2,00E+07
-4,00E+07
-6,00E+07
-8,00E+07
Permanent
loads
Perm. portati
0 50 100 150 200 250 300
Second 50%
of external
prestressing
Ritesatura cavi
Longitudinal Coordinata axis [m] [m]

58
Bending moment diagrams: end of service life (50 years)
8,00E+07
Bending moment [Nm]
Momenti [Nm]
6,00E+07
4,00E+07
2,00E+07
0,00E+00
-2,00E+07
-4,00E+07
-6,00E+07
-8,00E+07
Perm. portati
0 50 100 150 200 250 300
50 50 years anni
Permanent
loads
Second 50%
Ritesatura cavi
50 anni of external
prestressing
Longitudinal Coordinata axis [m] [m]

59
Evolution of stresses during construction
and service life of
FLAT WEBS SOLUTION

60
Axial stress in concrete top slab – continuity support section
0,00
0 50 100 150 200 250 300 350 400
-2,00
Tiro Internal dei cavi tendons interni
prestressing
Axial stress [MPa]
Tensioni Normali [MPa]
-4,00
-6,00
-8,00
-10,00
-12,00
Tiro First dei 50% cavi of esterni external
campate prestressing laterali (50%) on
lateral spans
Applicazione Permanent loads carichi
permanenti introduction portati
First 50% of external
Tiro dei cavi esterni Second 50% of external
prestressing on central Ritesatura cavi esterni
campate spans centrali (50%) prestressing everywhere
Tempi [gg]
Time [days]

61
Axial stress in concrete top slab – continuity support section
-7,00
100 1000 10000 100000
Axial stress [MPa]
Tensioni Normali [MPa]
-8,00
-9,00
-10,00
50 years: end of
50 service anni life
377 gg. 377 days: end of
construction
-11,00
Tempi [gg]
Time [days]

62
Axial stress in concrete bottom slab – continuity support section
0,00
0 50 100 150 200 250 300 350 400
Axial stress [MPa]
Tensioni Normali [MPa]
-1,00
-2,00
-3,00
-4,00
-5,00
-6,00
-7,00
-8,00
-9,00
Tiro Internal dei cavi tendons interni
prestressing
First 50% of external
Tiro prestressing dei cavi esterni on central
campate spans centrali (50%)
First Tiro 50% dei cavi of external esterni
Ritesatura Second 50% cavi esterni of external
prestressing campate on laterali (50%) spans
prestressing everywhere
Applicazione Permanent loads carichi
permanenti introduction portati
Tempi [gg]
Time [days]

63
Axial stress in concrete bottom slab – continuity support section
-6,00
100 1000 10000 100000
Axial stress [MPa]
Tensioni Normali [MPa]
-6,50
-7,00
-7,50
377 377 days: gg. end of
construction
50 50 anni years:
end of
service life
-8,00
Tempi [gg]
Time [days]

64
Axial stress in steel top flange – continuity support section
60,00
0 50 100 150 200 250 300 350 400
Axial stress [MPa]
Tensioni Normali [MPa]
40,00
20,00
0,00
-20,00
-40,00
Tiro Internal dei cavi tendons interni
prestressing
Applicazione Permanent loads carichi
permanenti introduction portati
-60,00
-80,00
-100,00
Tiro First dei 50% cavi of esterni external
campate prestressing laterali on (50%)
lateral spans
First 50% of external
Tiro prestressing dei cavi esterni on
campate central centrali spans(50%)
Tempi [gg]
Time [days]
Ritesatura Second 50% cavi esterni of external
prestressing everywhere

65
Axial stress in steel top flange – continuity support section
-80,00
100 1000 10000 100000
-100,00
377 377 days: gg.
end of
construction
Axial stress [MPa]
Tensioni Normali [MPa]
-120,00
-140,00
-160,00
50 50 anni years:
end of
service life
-180,00
Tempi [gg]
Time [days]

66
Axial stress in steel bottom flange – continuity support section
0,00
0 50 100 150 200 250 300 350 400
Axial stress [MPa]
Tensioni Normali [MPa]
-20,00
-40,00
-60,00
-80,00
-100,00
-120,00
-140,00
Tiro First dei 50% cavi of esterni external
campate prestressing laterali (50%) on
lateral spans
Internal tendons
Tiro prestressing dei cavi interni
First 50% of external
Tiro prestressing dei cavi esterni on
campate central centrali spans(50%)
Applicazione Permanent loads carichi
permanenti introduction portati
Tempi [gg]
Time [days]
Second 50% of external
Ritesatura prestressing cavi everywhere esterni

67
Axial stress in steel top flange – continuity support section
-100,00
100 1000 10000 100000
Axial stress [MPa]
Tensioni Normali [MPa]
-120,00
-140,00
-160,00
377 days:
end 377 of gg.
construction
50 years:
end of
50
service
anni
life
-180,00
Tempi [gg]
Time [days]

68
Axial stress in concrete top slab – midspan key segment
1,00
0 50 100 150 200 250 300 350 400
0,00
Axial stress [MPa]
Tensioni Normali [MPa]
-1,00
-2,00
-3,00
-4,00
-5,00
First 50% of external
Tiro
prestressing
dei cavi esterni
on
campate central centrali spans(50%)
Applicazione Permanent loads carichi
permanenti introduction portati
Second 50% of external
Ritesatura cavi esterni
prestressing everywhere
-6,00
Tempi [gg]
Time [days]

69
Axial stress in concrete top slab – midspan key segment
-4,00
100 1000 10000 100000
-4,50
Axial stress [MPa]
Tensioni Normali [MPa]
-5,00
-5,50
377 days:
end of
construction
377 gg.
50 anni years:
end of
service life
-6,00
Tempi [gg]
Time [days]

70
Axial stress in concrete bottom slab – midspan key segment
2,00
0 50 100 150 200 250 300 350 400
1,00
Axial stress [MPa]
Tensioni Normali [MPa]
0,00
-1,00
-2,00
-3,00
-4,00
-5,00
-6,00
First 50% of external
Tiro dei cavi esterni
prestressing on
campate
central
centrali
spans
(50%)
Applicazione Permanent loads carichi
permanenti introduction portati
-7,00
-8,00
-9,00
Tempi [gg]
Time [days]
Second 50% of external
prestressing
Ritesatura
everywhere
cavi esterni

71
Axial stress in concrete bottom slab – midspan key segment
-6,00
100 1000 10000 100000
Axial stress [MPa]
Tensioni Normali [MPa]
-6,50
-7,00
-7,50
377 days:
end of
construction 377 gg.
50 50 anni years:
end of
service life
-8,00
Tempi [gg]
Time [days]

72
Modeling of
CORRUGATED WEBS

Overall characteristics
73
• High longitudinal deformability (accordion effect)
• better U.L.S. shear buckling behaviour;
• Out of the plane inertia (transverse bending/ folded plate) .

An analytical method to calculate this ratio is developed
through the use of a model that satisfies equilibrium and
compatibility conditions.
74

75
An analytical method to calculate this ratio is developed
through the use of a model that satisfies equilibrium and
compatibility conditions.
Hypothesis: the web is under
pure bending moment and the
axial deformation in each
plate element of the
corrugated web is negligible.
δ
B
VIRTUAL WORKS PRINCIPLE
M
i
⋅ M F ⋅c
⋅ senα
⋅c
⋅ senα
F ⋅c
⋅ senα
⎛ x ⎞ ⎛
∫ dS =
dx +
⎜1
− ⎟ ⋅ c ⋅ sen ⎜1
−
EJ
EJ
EJ
⎝
c
⎠
⎝
= ∫ ∫
3D
α
EJ S
A B
C
x ⎞
⎟dx
c
⎠
δ
3D
=
F ⋅c
2
⋅ sen α
⎜
⎛ a + EJ ⎝
2
c ⎞
⎟
3⎠

76
An analytical method to calculate this ratio is developed
through the use of a model that satisfies equilibrium and
compatibility conditions.
Hypothesis: the web is under
pure bending moment and the
axial deformation in each
plate element of the
corrugated web is negligible.
δ
B
VIRTUAL WORKS PRINCIPLE
M
i
⋅ M F ⋅c
⋅ senα
⋅c
⋅ senα
F ⋅c
⋅ senα
⎛ x ⎞ ⎛
∫ dS =
dx +
⎜1
− ⎟ ⋅ c ⋅ sen ⎜1
−
EJ
EJ
EJ
⎝
c
⎠
⎝
= ∫ ∫
3D
α
EJ S
A B
C
x ⎞
⎟dx
c
⎠
∆
3D
2 2
F ⋅c
⋅ sen α ⎛
= 48 ⎜a
+
3
E ⋅t
⋅ H ⎝
∆
FLAT
=
w
F ⋅ L
H ⋅t
w
h
⋅ E
c ⎞
⎟
3 ⎠
r
eq
=
∆
∆
=
48⋅c
L
2
⋅ sen α ⎛
⎜ a +
2
⋅t
⎝ 3
2
3D
c
flat
h
w
⎞
⎟
⎠

77
Longitudinal profile
Reduction of
modulus of
elasticity to take
into account
longitudinal
stiffness
Web corrugation
ES
E
S
=
350

Comparison of results between corrugated
and flat webs
78

79
Axial stress in concrete top slab – continuity support section
0,00
0 50 100 150 200 250 300 350 400
-2,00
Tiro Internal dei cavi tendons interni
prestressing
Anime Flat webs lisce
Anime Corrugated corrugate webs
Axial stress [MPa]
Tensioni Normali [MPa]
-4,00
-6,00
-8,00
-10,00
-12,00
First 50% of external
Tiro dei cavi esterni
campate
prestressing
laterali (50%)
on
lateral spans
First Tiro 50% dei cavi of esterni external
prestressing campate centrali on central (50%)
spans
Tempi [gg]
Time [days]
Permanent loads
introduction
Applicazione carichi
permanenti portati
Ritesatura Second cavi 50% esterni of
external prestressing
everywhere

80
Axial stress in concrete top slab – continuity support section
-7,00
100 1000 10000 100000
Axial stress [MPa]
Tensioni Normali [MPa]
-8,00
-9,00
-10,00
-11,00
Anime Flat webs lisce
Anime Corrugated corrugate webs
377 377 days: gg.
end of
construction
50 years:
end of
50 anni
service life
-12,00
Tempi [gg]
Time [days]

81
Axial stress in concrete bottom slab – continuity support section
0,00
-2,00
0 50 100 150 200 250 300 350 400
Internal tendons
prestressing
Tiro dei cavi interni
Anime Flat webs lisce
Anime
Corrugated
corrugate
webs
Axial stress [MPa]
Tensioni Normali [MPa]
-4,00
-6,00
First 50% of external
prestressing on central
Tiro dei cavi esterni
campate spans centrali (50%)
First 50% of external
prestressing on lateral spans
Tiro dei cavi esterni
campate laterali (50%)
Second 50% of external
prestressing everywhere
Ritesatura cavi esterni
-8,00
-10,00
Permanent loads
introduction
Applicazione carichi
permanenti portati
Tempi [gg]
Time [days]

82
Axial stress in concrete bottom slab – continuity support section
-6,00
100 1000 10000 100000
-6,50
Anime Flat webs lisce
Anime Corrugated corrugate webs
Axial stress [MPa]
Tensioni Normali [MPa]
-7,00
-7,50
-8,00
-8,50
377 377 days: gg.
end of
construction
50 years:
50 end anni of
service life
-9,00
Tempi [gg]
Time [days]

83
Axial stress in steel top flange – continuity support section
80,00
0 50 100 150 200 250 300 350 400
60,00
40,00
Internal tendons
Tiro dei cavi interni
prestressing
Anime Flat webs lisce
Anime Corrugated corrugate webs
Axial stress [MPa]
Tensioni Normali [MPa]
20,00
0,00
-20,00
-40,00
Permanent loads
Applicazione carichi
permanenti introduction
portati
-60,00
-80,00
-100,00
Tiro dei cavi esterni
campate laterali (50%)
First 50% of external
prestressing on
lateral spans
First 50% of external
Tiro dei cavi esterni
campate
prestressing
centrali (50%)
on
central spans
Tempi [gg]
Time [days]
Second 50% of
external prestressing
everywhere
Ritesatura cavi esterni

84
Axial stress in steel top flange – continuity support section
-60,00
-80,00
100 1000 10000 100000
377 days:
377 end gg. of
construction
Axial stress [MPa]
Tensioni Normali [MPa]
-100,00
-120,00
-140,00
-160,00
Anime Flat webs lisce
Anime Corrugated corrugate webs
50 years:
end of
service life
50 anni
-180,00
Tempi [gg]
Time [days]

85
Axial stress in steel bottom flange – continuity support section
0,00
0 50 100 150 200 250 300 350 400
Axial stress [MPa]
Tensioni Normali [MPa]
-20,00
-40,00
-60,00
-80,00
-100,00
-120,00
-140,00
Internal tendons
prestressing
Tiro dei cavi interni
First Tiro 50% dei of cavi external esterni
prestressing campate on centrali spans (50%)
Anime Flat webs lisce
Anime Corrugated corrugate webs
Permanent loads
Applicazione carichi
permanenti introduction portati
Second 50% of external
prestressing everywhere
Ritesatura cavi esterni
-160,00
-180,00
First Tiro dei 50% cavi of esterni external
campate prestressing laterali (50%) on
lateral spans
Tempi [gg]
Time [days]

86
Axial stress in steel bottom flange – continuity support section
-100,00
100 1000 10000 100000
Axial stress [MPa]
Tensioni Normali [MPa]
-120,00
-140,00
-160,00
-180,00
-200,00
377 days:
377 gg.
end of
construction
Anime Flat webs lisce
Anime Corrugated corrugate webs
50 years:
50 anni
end of
service life
-220,00
-240,00
Tempi [gg]
Time [days]

Cumbering design
87

88
Cumbering design
Displacements without cumbering
1,00E-03
Abbassamento Vert. displacement [m]
[m]
0,00E+00
40,00 45,00 50,00 55,00 60,00 65,00 70,00 75,00 80,00 85,00
-1,00E-03
-2,00E-03
-3,00E-03
-4,00E-03
-5,00E-03
-6,00E-03
-7,00E-03
End of
Fine concio 1
segment one
-8,00E-03
-9,00E-03
Longitudinal Coordinata axis [m]

89
Cumbering design
Displacements without cumbering
1,00E-03
Abbassamento Vert. displacement [m]
[m]
0,00E+00
40,00 45,00 50,00 55,00 60,00 65,00 70,00 75,00 80,00 85,00
-1,00E-03
-2,00E-03
-3,00E-03
-4,00E-03
-5,00E-03
-6,00E-03
-7,00E-03
Prestressing
Tiro cavi 1-2
of tendons 1
and 2
End of
segment one
Fine concio 1
-8,00E-03
-9,00E-03
Longitudinal Coordinata axis [m]

90
Cumbering design
Displacements without cumbering
1,00E-03
Vert. Abbassamento displacement [m]
[m]
0,00E+00
40,00 45,00 50,00 55,00 60,00 65,00 70,00 75,00 80,00 85,00
-1,00E-03
-2,00E-03 Prestressing
of tendons 1
-3,00E-03
Tiro and cavi 2 1-2 Fine End concio of 1
-4,00E-03
segment 1
-5,00E-03
-6,00E-03
-7,00E-03
-8,00E-03
End of
segment 2
Fine concio 2
-9,00E-03
Longitudinal Coordinata axis [m]

91
Cumbering design
Displacements without cumbering
1,00E-03
Abbassamento Vert. displacement [m]
[m]
0,00E+00
40,00 45,00 50,00 55,00 60,00 65,00 70,00 75,00 80,00 85,00
-1,00E-03
-2,00E-03
-3,00E-03
-4,00E-03
-5,00E-03
-6,00E-03
-7,00E-03
-8,00E-03
Prestressing
of tendons 1
and 2
End of
segment 1
Tiro cavi 1-2 Fine concio 1
Tiro cavi 3-5
Prestressing
tendons 3 , 4, 5
End of
segment 2
Fine concio 2
-9,00E-03
Longitudinal Coordinata axis [m]

92
Cumbering design
Displacements without cumbering
5,00E-03
Vert. Abbassamento displacement [m]
[m]
0,00E+00
20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 110,00
-5,00E-03
-1,00E-02
-1,50E-02
-2,00E-02
-2,50E-02
-3,00E-02
Fine End concio of 3
segment 3
-3,50E-02
-4,00E-02
Longitudinal Coordinata axis [m]

93
Cumbering design
Displacements without cumbering
5,00E-03
Vert. Abbassamento displacement [m]
[m]
0,00E+00
20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 110,00
-5,00E-03
-1,00E-02
-1,50E-02
-2,00E-02
-2,50E-02
-3,00E-02
Tiro cavi 6-8
Prestressing of
tendons 6, 7 ,8
End of
segment 3
Fine concio 3
-3,50E-02
-4,00E-02
Longitudinal Coordinata axis [m]

94
Cumbering design
Displacements without cumbering
5,00E-03
Vert. Abbassamento displacement [m]
[m]
0,00E+00
20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 110,00
-5,00E-03
-1,00E-02
-1,50E-02
-2,00E-02
-2,50E-02
-3,00E-02
-3,50E-02
End of
segment 4
Fine concio 4
Tiro cavi 6-8
Prestressing of
tendons 6, 7 ,8
End of
segment 3
Fine concio 3
-4,00E-02
Longitudinal Coordinata axis [m]

95
Cumbering design
Displacements without cumbering
5,00E-03
Vert. Abbassamento displacement [m]
[m]
0,00E+00
20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 110,00
-5,00E-03
-1,00E-02
-1,50E-02
-2,00E-02
-2,50E-02
-3,00E-02
-3,50E-02
Prestressing
tendons 9 , 10 ,11
Tiro cavi 9-11
End of
segment 4
Fine concio 4
Tiro cavi 6-8
Prestressing of
tendons 6, 7 ,8
End of
segment 3
Fine concio 3
-4,00E-02
Longitudinal Coordinata axis [m]

96
Cumbering design
Displacements without cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
10,00 30,00 50,00 70,00 90,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
-5,00E-02
-6,00E-02
-7,00E-02
-8,00E-02
Longitudinal Coordinata axis [m]
End of
segment 5
Fine concio 5

97
Cumbering design
Displacements without cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
10,00 30,00 50,00 70,00 90,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
-5,00E-02
-6,00E-02
Prestressing of
tendons 12, 13 ,14
Tiro cavi 12-14
-7,00E-02
-8,00E-02
Longitudinal Coordinata axis [m]
End of
segment 5
Fine concio 5

98
Cumbering design
Displacements without cumbering
2,00E-02
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
10,00 30,00 50,00 70,00 90,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
-5,00E-02
-6,00E-02
Grouting of internal
tendons
Sigillatura cavi interni
-7,00E-02
-8,00E-02
Longitudinal Coordinata axis [m]

99
Cumbering design
Displacements without cumbering
2,00E-02
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
10,00 30,00 50,00 70,00 90,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
-5,00E-02
-6,00E-02
-7,00E-02
-8,00E-02
Grouting of internal
tendons
Sigillatura cavi interni
Longitudinal Coordinata axis [m]
First 50% of lateral
Precompressione
campate spans laterali external (50%)
prestressing

100
Cumbering design
Displacements without cumbering
2,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-2,00E-02
-4,00E-02
-6,00E-02
-8,00E-02
Closure of key
segments
Sutura campate
-1,00E-01
Longitudinal Coordinata axis [m]

101
Cumbering design
Displacements without cumbering
2,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-2,00E-02
-4,00E-02
-6,00E-02
-8,00E-02
-1,00E-01
Closure of key
segments
Sutura campate
First 50% of central
spans external
Prec. Est. Campate
centrali prestressing (50%)
Longitudinal Coordinata axis [m]

102
Cumbering design
Displacements without cumbering
2,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-2,00E-02
-4,00E-02
-6,00E-02
-8,00E-02
-1,00E-01
Closure of key
segments
Sutura campate
First 50% of central
spans external
Prec. Est. Campate
centrali prestressing (50%)
Longitudinal Coordinata axis [m]
Introduction of
permanent loads
Applicazione carichi
perm. portati

103
Cumbering design
Displacements without cumbering
2,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-2,00E-02
-4,00E-02
-6,00E-02
-8,00E-02
-1,00E-01
Closure of key
segments
Sutura campate
First 50% of central
spans external
Prec. Est. Campate
centrali prestressing (50%)
Longitudinal Coordinata axis [m]
Introduction of
Applicazione carichi
perm. permanent portati loads
Second 50% of
external tendons
prestressing
Ritesatura cavi
esterni

104
Cumbering design
Displacements without cumbering
4,00E-02
Vert. Abbassamento displacement [m]
[m]
2,00E-02
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-2,00E-02
-4,00E-02
-6,00E-02
-8,00E-02
-1,00E-01
1 Year after
construction end
1 anno
Longitudinal Coordinata axis [m]

105
Cumbering design
Displacements without cumbering
4,00E-02
Vert. Abbassamento displacement [m]
[m]
2,00E-02
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-2,00E-02
-4,00E-02
-6,00E-02
-8,00E-02
-1,00E-01
1 Year after
construction end
1 anno 4 anni
4 years after
construction end
Longitudinal Coordinata axis [m]

106
Cumbering design
Displacements without cumbering
4,00E-02
Vert. Abbassamento displacement [m]
[m]
2,00E-02
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-2,00E-02
-4,00E-02
-6,00E-02
-8,00E-02
-1,00E-01
1 Year after
construction end
4 years after
construction end
1 anno 4 anni 16 anni
Longitudinal Coordinata axis [m]
16 years after
construction end

107
Cumbering design
Displacements without cumbering
4,00E-02
Vert. Abbassamento displacement [m]
[m]
2,00E-02
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-2,00E-02
-4,00E-02
-6,00E-02
-8,00E-02
-1,00E-01
1 Year after
construction end
4 years after
construction end
16 years after
construction end
1 anno 4 anni 16 anni 50 anni
Longitudinal Coordinata axis [m]
50 years after
construction end

108
Cumbering design
Displacements WITH cumbering
3,00E-02
Vert. Abbassamento displacement [m]
[m]
2,00E-02
1,00E-02
End of
segment 3
Fine concio 3
0,00E+00
20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
-5,00E-02
Longitudinal Coordinata axis [m]

109
Cumbering design
Displacements WITH cumbering
Vert. Abbassamento displacement [m]
[m]
3,00E-02
2,00E-02
1,00E-02
Prestressing of
tendons 6, 7, 8
Tiro cavi 6-8
End of
segment 3
Fine concio 3
0,00E+00
20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
-5,00E-02
Longitudinal Coordinata axis [m]

110
Cumbering design
Displacements WITH cumbering
Vert. Abbassamento displacement [m]
[m]
3,00E-02
2,00E-02
1,00E-02
Prestressing of
tendons 6, 7, 8
Tiro cavi 6-8
End of
segment 3
Fine concio 3
0,00E+00
20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
Fine concio 4
-5,00E-02
Longitudinal Coordinata axis [m]

111
Cumbering design
Displacements WITH cumbering
Vert. Abbassamento displacement [m]
[m]
3,00E-02
Prestressing of
tendons Tiro 6, cavi 7, 86-8
2,00E-02
End of
1,00E-02
Fine segment concio 3
0,00E+00
20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
Tiro cavi 9-11
-4,00E-02
Fine concio 4
-5,00E-02
Longitudinal Coordinata axis [m]

112
Cumbering design
Displacements WITH cumbering
2,00E-02
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
10,00 30,00 50,00 70,00 90,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
End of
segment 5
Fine concio 5
-5,00E-02
-6,00E-02
Longitudinal Coordinata axis [m]

113
Cumbering design
Displacements WITH cumbering
2,00E-02
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
10,00 30,00 50,00 70,00 90,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
Prestressing of
tendons 12, 13, 14
Tiro cavi 12-14
End of
segment 5
Fine concio 5
-5,00E-02
-6,00E-02
Longitudinal Coordinata axis [m]

114
Cumbering design
Displacements WITH cumbering
Vert. Abbassamento displacement [m]
[m]
2,00E-02
1,00E-02
0,00E+00
10,00 30,00 50,00 70,00 90,00 110,00
-1,00E-02
-2,00E-02
Grouting of internal
Sigillatura cavi interni
tendons
-3,00E-02
-4,00E-02
Longitudinal Coordinata axis [m]

115
Cumbering design
Displacements WITH cumbering
Vert. Abbassamento displacement [m]
[m]
2,00E-02
1,00E-02
0,00E+00
10,00 30,00 50,00 70,00 90,00 110,00
-1,00E-02
-2,00E-02
-3,00E-02
Grouting of internal
Sigillatura cavi interni
tendons
First 50% of lateral
Precompressione
campate spans laterali external (50%)
prestressing
-4,00E-02
Longitudinal Coordinata axis [m]

116
Cumbering design
Displacements WITH cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
Closure of key
segments
Sutura campate
Longitudinal Coordinata axis [m]

117
Cumbering design
Displacements WITH cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
Closure of key
segments
Sutura campate
First 50% of central
spans external
Prec. Est. Campate
centrali prestressing (50%)
Longitudinal Coordinata axis [m]

118
Cumbering design
Displacements WITH cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
Closure of key
segments
Sutura campate
First 50% of
central spans
external
Prec. Est. Campate
centrali prestressing (50%)
Longitudinal Coordinata axis [m]
Introduction of
Applicazione carichi
perm. permanent portati loads
Second 50% of
external tendons
prestressing
Ritesatura cavi
esterni

119
Cumbering design
Displacements WITH cumbering
1,00E-02
Abbassamento [m]
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-1,00E-02
-2,00E-02
-3,00E-02
-4,00E-02
Closure of key
segments
Sutura campate
First 50% of central
spans external
Prec. Est. Campate
centrali prestressing (50%)
Longitudinal Coordinata axis [m]
Introduction of
permanent loads
Applicazione carichi
perm. portati

120
Cumbering design
Displacements WITH cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
5,00E-03
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-5,00E-03
-1,00E-02
-1,50E-02
1 year after
construction 1 anno
Longitudinal Coordinata axis [m]

121
Cumbering design
Displacements WITH cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
5,00E-03
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-5,00E-03
-1,00E-02
-1,50E-02
1 year after
construction
1 anno 4 anni
4 years after
construction
Longitudinal Coordinata axis [m]

122
Cumbering design
Displacements WITH cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
5,00E-03
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-5,00E-03
-1,00E-02
-1,50E-02
1 year after
construction
4 years after
construction
1 anno 4 anni 16 anni
Longitudinal Coordinata axis [m]
16 years after
construction

123
Cumbering design
Displacements WITH cumbering
1,00E-02
Vert. Abbassamento displacement [m]
[m]
5,00E-03
0,00E+00
8,00 58,00 108,00 158,00 208,00 258,00
-5,00E-03
-1,00E-02
-1,50E-02
1 year after
construction
4 years after
construction
16 years after
construction
1 anno 4 anni 16 anni 50 anni
Longitudinal Coordinata axis [m]
50 years after
construction

Conclusions
124

125
Sustainability aspects
Durability ⇒
Economy ⇒
Environmental impact ⇒
Maintenance ⇒
Rehabilitation ⇒
No tensile stresses in concrete in SLS
(Frequent combination)
Time saving and elimination of
launching girder
Elimination of storage areas for
segments
Very easy inspection and control of
external tendons
Substitution of external tendons without
significant limitation to traffic flow

126
Materials amount
Flat webs
Corrugated webs
Concrete 0.80 m 3 /m 2 0.80 m 3 /m 2
Steel 170 kg/m 2 155 kg/m 2
Prestressing steel 60 kg/m 2 56 kg/m 2
Ordinary reinforcement 170 kg/m 2 170 kg/m 2

127
Use of steel
With plane webs
Main girders:
Partial total
61 kg/m 2 web weight
34 Kg/m 2 flanges weight
15 Kg/m 2 connections, studs, bolts, plates, etc…
16 Kg/m 2 web stiffeners
15 Kg/m 2 truss diaphragms
141 kg/m 2 + 29 Kg/m 2 for pier segments and
prestressing deviators

128
Use of steel
With corrugated webs
Main girders:
Partial total
74 kg/m 2 web weight
34 Kg/m 2 flanges weight
17 Kg/m 2 connections, studs, bolts, plates, etc…
0 Kg/m 2 web stiffeners
0 Kg/m 2 truss diaphragms
125 kg/m 2 + 29 Kg/m 2 for pier segments and
prestressing deviators = 154 Kg/m 2

129
Thank u for kind
attention !