Steel Composite Bridges Germany

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1

Steel and composite bridges in Germany

State of the ArtUniv.-Prof. Dr.-Ing. G. Hanswille

Institute for Steel and Composite StructuresUniversity of Wuppertal

Germany

Univ.-Prof. em. Dr.-Ing. Dr. h.c. G. Sedlacek

Institute for Steel and Lightweight StructuresRWTH Aachen

Germany

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Introduction

Typical composite road bridges with open sections and box girders

Composite box girders with wide cantilevering concrete decks

Composite bowstring arches

Composite trusses

Composite bridges for small and medium spans

Cable stayed bridges

Canal bridges

Contents

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Very slender and aesthetic bridges due to the optimal combination .of high tensile strength of structural steel and the high compressive strength of concrete High durability of normal reinforced concrete decks due to restrictive crack width limitation. In comparison with steel bridges composite bridges have a better behaviour with regard to freezing in winter.Because the low dead weight of the composite bridges deck is, composite bridges have advantages with regard to the foundation and settlements of supports.Due to innovative erection methods composite bridges are often used for bridges over passing existent railways or highways without any restrictions for the traffic. Where existing freeways with two lanes are widened the short erection time of composite bridges avoids longer restrictions for traffic.

Advantages of composite bridges

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Werra-Bridge Einhausen

Composite Bridges with open and closed cross-sections

3

5

16,75m12,75m 2,002,00

2,5752,5755,80

4,30 4,308,15m

35 cm45 cm

2,5%

6,80m

55cm 40 cm

25cm

25cm

3,007,15

1,80

45cm2,5%

2,5%

box girder

5,8035cm

1,803,00

25cm

cross-section with two separated box girders

airtight welded box girders

plate girder bridge with three rolled or welded main girders

Typical cross-sections for composite bridges

6

view

5,00

11,00 11,003,25

25,25 m

2875 1300 5700 mm 1300 2475

cross-section at midspan

7000 mm

55 72,5 80,0 80,0 80,0 75,0 72,5 67,0 58,0 40,0680,0

290460

Bridge Schleusetal

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7

Bridge Schleusetal

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Bridge Schleusetal

transportation of steel girderson site

erection of steel girders bycranes

casting of the concrete deck bymoveable formwork

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9

Examples for formwork systems

retractable console

wedges

formwork tables

formwork tables on temporary consoles

scaffold beam

rollers

10

Bridge across the river Ruhr near Hagen-Freeway A1

14,50 14,50 1,961,96 1,50 1,50

3,01 3,012,502,50 6,00 6,002,502,50 3,52 3,52

35,06m

73,48m 95,77m 71,83m

4,00m2,70 1,30

1,25

4,50 4,

76 3,20 3,46

3% 3%

view

cross-sectionat midspan

cross-sectionat supports

concrete end cross girder

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11

Bridge across the river Ruhr near Hagen-Freeway A1

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30.00

3.0011.50

2.00

6.23 4.36

6.92

2.00

4.01 6.99 4.00

3.75

concrete C 50/60

concrete C35/45

cross-section at midspan

cross-section at support

0 1 2 3 4 5

95.00 154.00

362.00

68.00 58.00470.00

3.30

7.00

3.30

7.00

3.30

3.30

3.30

HHW 366.00

3.7511.50

4.39

0,52 0,34

0,35

Bridge Neuötting -Double composite box girder

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13

Double composite bridge Neuötting

box girder with double composite action at internal supports

composite bottom flange

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Box girders with corrugated webs

Bridge Altwipfergrund

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15

30,5 40,0 42,0 42,0 42,0 42,0 42,0 36,0

316,5

view

cross-section

36,75

2,25 14,501,75 1,50

2,2514,50

7,75 7,75

6% 4%0,00 0,00 4%6%15%35404%

18,50 18,25

3,603,35 3,353,355,905,90 5,655,65

-2,95

1,60

Bridge Langerfeld – Freeway A1

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Langerfelder Bridge – Highway A1

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Langerfelder Bridge – Highway A1Detailing at internal supports

elastomerbearings wedge

shaped bearing plate

transverse stiffener for hydraulic press

support stiffener

plate for jacking supports by hydraulic press in case of exchanging bearings

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Bridge Albrechtsgraben

Composite box girders with wide cantilevering concrete decks

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Composite box girders with wide concrete decks

Bridge Reichenbachtal Bridge Elben

Bridge Schwarza Bridge Oehde

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Bridge Wilde Gera

3030 36 3642424242424242424242252m

Schweinfurt

DB

3,30

Wilde Gera14,50

1,80Erfurt

28,00m

10,0010,002,00 2,001,501,50

5,505,50

3,155,001,203,803,805,003,15 1,203535

longitudinal beamstransverse tension member

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Bridge Wilde Gera

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Bridge Wilde Gera – Highway A71

transverse framestransverse steel tension members

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23


cantilever erection of the arch

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Bridge girder during launching


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25

Bridge Albrechtsgraben - Highway A71

45

140 130 120 110 100 90 80 70 60 50 40 30 20 10

55 60 70 70 70 45 40 40 45 70 60 50 45

770

150

29,0025,00

2,002,00

6,001,504,156,00 1,50 4,15

26

Bridge Albrechtsgraben - Highway A71

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Different detailing of transverse tension members

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Joints between the longitudinal girders/box girders and the transverse tension members

Bridge SchwarzaBridge Albrechtsgraben

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pulling down joint horizontal loops

tension member

vertical stirrupps

Zs

Zs

Za

Dc

Zs,q

A A

section A-A

Detailing of the transverse tension members

outside longitudinal girder

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Acessment of different solutions for transverse tension members

complicate connection caused by the eccentricity between the tension member and the top flanges of the box girder

no significant stresses in the steel tension member due to local loads

slabs with constant depth and haunches in longitudinal direction are possible, uni-axial load transfer in transverse direction

higher stresses due to local loads. Resistance of the tension member to normal forces, bending moments and vertical shear should be considered

haunched concrete slab, expensive formwork, bi-axial load transfer in transverse and longitudinal direction

economical simple connections with the top flanges of the box girder and the secondary longitudinal girders

high stresses due to local concentrated wheel loads (Fatigue resistance)

a constant depth of the slab over the total width of the bridge deck is required, uni-axial load transfer in transverse direction

connectionsinternal forces in the tension member

geometry of the concrete slab

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Sequense of casting of concrete

Method I : continuous in one direction

Method II: continuous in one direction but regions at internal supports are casted in a second step after the concrete in mid-span regions is effective

Method III: span-wise in reverse direction

Method I

Method II

Method III

10 20 30 40 50 60 70 80 90 100 110 120

1 ‰

45 55 70 70 70 70 70 70 70 55 45690

cross-section28,50

3,80

70,0

17,53 x 15,0 3 x 15,0 3 x 15,017,5 7,57,57,5

70,0

121110987654321

111091276583214

910111256781234

7,5

32

Method I

Method II

Method III

My= -105,3My= -103,2 My= -107,5

My= -31,9 My= -31,9My= -45,4My= -43,7

My= 27,2 My= 28,1My= 25,6

My= -32,5 My= -33,5

My= 27,3 My= 25,4My= 26,5[My in MNm]

++

+

+ + +

-

-

-

--

- -

bending moments acting on the composite sectiondue to dead weight of concrete

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formwork carriage for cantilevers

Formwork carriage running on the top of the deck


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Bridge Wilde Gera

Formwork carriage running on the top of the deck

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35

formwork carriage for outer cantilevers

Formwork underneath the concrete deck

Bridge Albrechtsgraben


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Bridge Schwarza

Formwork underneath the concrete deck (system Kirchner)

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Exchange of concrete decks

Normally it is a general requirement in Germany to have separate bridges for each traffic direction in order to be able to divert the full traffic on the remaining bridge in case of major maintenance work on the other. The concrete deck is the most vulnerable part of a bridge section. With regard to the expected intensive increase of road traffic and local wheel loads in future, the concrete deck must be regarded as a wearing part in contrast to the steel structure with implication of different lifetimes of the concrete deck and the steel structure.

In case of one main composite box girder for both traffic directions the flow of traffic has to be maintained in both directions just on one half of the bridge during a future replacement of the bridge deck. For this procedure the bridge deck will be partially cut out with high-pressure water method and will be replaced by a new bridge deck. During this procedure significant additional stresses result in the superstructure, which have to be considered during design and construction.

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Different possibilities for the exchange of the concrete slab

exchange over a quarter of the bridge in two steps

exchange of one half of the deck with additional horizontal bracing

A

Horizontal bracing

B

C

B1

B2

exchange of one half of the deck The width of the span is the most important factor for choosing the different methods. Method A can only be used for spans up to 50 m. Methods B or C are possible for the exchange of the concrete deck of bridges with larger spans of up to 100 m.

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418,30 m

44,70 44,7056,056,0 72,80 64,072,80

00 10 20 30 40 50 60 703,8%

5600 23103800

38005600

2,5%

3800

38002310

3785

Bridge Oehde – Freeway A1

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transverse tensionmember

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P1 P3 P2 P6 P4 P5 P9 P7 P8 P11 P10 P13 P12 P15 P14

concrete deck withpartially prefabricated

concrete elements

launching of the bridge withpartially prefabricated concrete

elements

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Composite bowstring arches

Saalebridge Besedau

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Composite bow string arches

Composite bow string arches with concrete decks are an often used system where the construction depth is limited e.g. for bridges over canals and rivers.The reinforced concrete deck is connected with the steel structure by horizontal bracings at the end of the bridge and is acting as a tension member in the main system.

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Normal forces in the concrete tension member

N= Ns+Na

Ns,cr Ns,crn

Ns,2

Na,2

Ns

Na

ΔNt,s

εs,2 εs,m

Ns= Ns,2 + ΔNt,s

Na= Na,2-ΔNts

N

The concrete member acts as a tension member in the main system.

For the normal forces in the concrete member the effects of tension stiffening of concrete between cracks should be considered.

Na= Na,2-ΔNts

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Bridge Ladbergen near Ladbergen– Highway A1

cross-section1500 1500

10100 9750 9750 101002000

800

1538

924

00

800

1538

924

00

view

plan

1500

104270

1985

019

850

2000

3958

end-bracing

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Detailing of composite bowstring arches

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47

Composite trusses

Bridge St. Kilian

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Composite truss bridge with double composite action – Bridge Nantenbach across the river Main

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view

C

C

B

B

C

C A

A

8 9 10

12,5 ‰

83,20m 208,00m 83,20m

25

49

6,80

1,20

3,953,958080

R=2650,00m

14,30

1,00

20 20

501,4

0

R=2650,00m

14,3020 20

501,4

0

15,26

2,00

1,20

2,60 2,602,60

80801,60 1,60

14,3020 20

R=2650,00m

6,80

1,10-

1,80

501,4

0

8080

1,00

1,00

Composite truss bridge with double composite action – Bridge Nantenbach across the river Main

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Composite truss bridge Kragenhofer

view

249,6058,40 73,60 58,4059,20

cross-section

143004700 2200 260022002600

5600 43504350

1552,35R=

400

70028

0

9000

26

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Bridge St. Kilian

28,5 m

5,0 m

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Bridge St. Kilian

steel trusses with hollowsections and cast iron nodes

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53

Composite bridges for small and medium spans

Bridge Oberhartmannsreuth

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Composite bridges with rolled sections for small an medium spans

Advantagesshort construction timesimple erection method because of no steelwork on site. steelwork only in the shopsmall total depth of the composite sectionconcrete slab without any pre-stressing

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Longitudinal reinforcement at internal supports

bottom layer of reinforcementAs,min = ∅16 a=10 cm

bQRT L+lb

The longitudinal reinforcement at internal supports should be placed over a length not smaller than L= 0,15 LSt where LSt is larger span length adjacent to the support considered.

at the end of the steel girder the number of shear connectors should be increased due to local introduction of the tensile force in the reinforcement in the composite section.

In case of sagging bending moments at internal supports due to temperature effects, traffic loads and settlements of supports for the tensile forces in the bottom flange a connection by steel plates or studs in combination with loops is required.

L+lb concentrated shear connectors at the end of the girder

lb-anchorage length of the reinforcement

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Detailing of transverse supporting beams in concrete

b>bmin b>90 cmbmin = 80cm (indirect support )

bmin= 60 cm (direct support)

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Detailing of partially prefabricated concrete elements

4,02,5

1,021

≥Cnom= 4,5cm

seal

hc

the depth of the concrete above the prefabricated elements hc should be not less than 20 cm within the traffic lanes. in other regions hc should not be less than 15 cm.

≥3cm

≥2,5 cm

Elastomeric support strips with a thickness of 2 cm and a width of 3 cm. The minimum value of pressing should be 3-5 mm and the maximum value should not exceed 10 mm.

mortar

shear reinforcement

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Casting of concrete

in case of smaller span length the transverse supporting beams and the concrete slab should be casted in one operation.

in case of larger span length or for bridges with a big total length at first the midspan regions and subsequently the internal supports and the transverse supporting beams should be casted.

L

0,15 L

casting of mid-span regions

casting of supporting beams and the slab at internal support

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VFT-Bridges with welded or rolled I-sections

steel girder in the shop

transport on site

installation by crane

steel girderprecastedconcrete flange

in situ concrete slab

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VFT-Filler beams

shear connection

3200

640

rolled section

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VFT-Filler beams

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Preflex - Beams

steel girder

prestressedcomposite bottom flange

The Preflex-Beam is a girder with a pre-stressed composite bottom flange where the pre-stressing is applied by elastic bending of the steel girder.

The pre-stress causes a higher bending resistance and a high flexural stiffness. Therefore the deflections under serviceability conditions very small. This type of beam is often used for railway and road bridges where the available construction depth is highly restricted. Ratios of span to structural depth up to 45 are possible for road bridges.

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Preflex Girders – pre-stressing of the concretebottom flange

campered steel girder

pre-stressing forces Fvapplied to the steelgirder (elastic bending)

casting of the concretebottom flange

removing of theprestressing force Fvafter hardening of concrete causescompressive stressesin the concrete bottomflange

casting of the concretetop flange on site

δFv Fv

Fv Fv

Fv Fv

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Composite bridge with Preflex-Girders

Hermann-Lieberum Bridge in Leipzig

continuous beam, span 33 m and construction depth 130 cm

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Cable stayed bridges

66

53,24 64,554 64,554 64,554 64,554 64,554 334,82 61,76

396,132 376,412

D C

10 20 30 40 50 60 70 80 90

cable stayed bridge Wesel across the river Rhein

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Cable stayed bridge Wesel across the river Rhein

cross-section axes 10 - 70

550 4250700

2800 4250700 550

550 400 5506150 6150

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Cable stayed bridge Wesel across the river Rhein

cross-section axes 70 - 90

35008750300087503500

5900 59002000

13800

2,5% 2,5%

77107710

27500 mm

35

69

Joint between the steel and the concrete section – concreteend cross girder


joint with overlapping steelplates and headed studs

70


36

71

4000

3295-3971

400

500

3000 30002000

4000

1000

1000

+145,30m

.+15,90

Pylon in high strength concrete

concrete section

composite section

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cables

Use of parallel strand cables of galvanizedwaxed and PE-coatedstrands instead of traditionally used fullylocked coil ropes.

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73

1070

80 90

stages I and II

stage III

stages III to VIII

stage IX

erection stages

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Canal bridges

canal bridge Lippe

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75

57,10106,20m57,10 6,30

10x5,7110x5,3110x5,3110x5,71

7,81

3,98 3,9834,04

cross-section

view

42,00 m

10 20 30 40

Canal bridge Magdeburg

76


total length 228 mspan length 57,1 m – 106,2 m – 57,1 mStructural steel 9.500 t

39

77

1900

740

4819

2440


1087

.5

740

transverse frame

78

Launching of the bridge

stage 2

stage 11

stage 17

stage 22

40

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Canal-bridge Lippe

A B C D

24,00m 24,80m 24,00m

4,75 28,00m 3,00

+56,50 NW

2,21 2,16 10,82 10,82 2,16 2,21

7,84

LT7 LT6 LT5 LT4 LT3 LT2 LT1

LT7 LT6 LT5 LT4 LT3 LT2 LT1

+56,50 NW

3,0028,00m4,75

30,40m2,21 4,33 4,33 4,33 4,33 4,33 4,33 2,21

80

Canal-bridge Lippe

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7th Japanese – German Bridge Colloquium Osaka 2007

Thank you very much for your attention

Documents

Steel Composite Bridges Germany