Steel and composite bridges in Germany State of the Art

Transcription

1 Steel and composite bridges in Germany State of the Art Univ.-Prof. Dr.-Ing. G. Hanswille Institute for Steel and Composite Structures University of Wuppertal Germany Univ.-Prof. em. Dr.-Ing. Dr. h.c. G. Sedlacek Institute for Steel and Lightweight Structures RWTH Aachen Germany 1 Contents 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 2 1

2 Advantages of composite bridges 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. 3 Composite Bridges with open and closed cross-sections Werra-Bridge Einhausen 4 2

3 Typical cross-sections for composite bridges plate girder bridge with three rolled or welded main girders 16,75m 2,00 2, cm 35 cm 5,80 12,75m 2,00 2,5% 5,80 2,575 25cm cross-section with two separated box girders 45cm 35cm 2,5% box girder 55cm 40 cm 2,5% 3,00 1,80 7,15 1,80 3,00 25cm 25cm airtight welded box girders 6,80m 4,30 8,15m 4,30 5 Bridge Schleusetal view 55 72,5 80,0 80,0 80,0 75,0 72,5 67,0 58,0 40,0 680,0 5,00 cross-section at midspan mm ,25 11,00 11, mm 25,25 m 6 3

4 Bridge Schleusetal 7 Bridge Schleusetal transportation of steel girders on site erection of steel girders by cranes casting of the concrete deck by moveable formwork 8 4

5 Examples for formwork systems formwork tables on temporary consoles retractable console rollers wedges formwork tables scaffold beam 9 Bridge across the river Ruhr near Hagen-Freeway A1 cross-section at supports 1,96 14,50 1,50 1,50 14,50 1,96 3% cross-section at midspan 3% concrete end cross girder 1,25 4,50 4,76 3,20 3,46 3,01 2,50 6,00 2,50 3,52 3,52 2,50 6,00 2,50 3,01 35,06m view 2,70 1,30 4,00m 73,48m 95,77m 71,83m 10 5

6 Bridge across the river Ruhr near Hagen-Freeway A1 11 Bridge Neuötting -Double composite box girder cross-section at midspan ,52 0, cross-section at support concrete C35/ , concrete C 50/ HHW

7 Double composite bridge Neuötting box girder with double composite action at internal supports composite bottom flange 13 Box girders with corrugated webs Bridge Altwipfergrund 14 7

8 Bridge Langerfeld Freeway A1 view 30,5 40,0 42,0 42,0 42,0 42,0 42,0 36,0 316,5 36,75 2,25 14,50 14,50 1,75 1,50 cross-section 7,75 7,75 2,25 4% 6% 40 0,00 4% 15% 0, % 4% -2,95 1,60 3,35 5,90 5,90 3,35 3,35 5,65 5,65 3,60 18,50 18,25 15 Langerfelder Bridge Highway A1 16 8

9 Langerfelder Bridge Highway A1 Detailing at internal supports support stiffener transverse stiffener for hydraulic press elastomer bearings plate for jacking supports by hydraulic press in case of exchanging bearings wedge shaped bearing plate 17 Composite box girders with wide cantilevering concrete decks Bridge Albrechtsgraben 18 9

10 Composite box girders with wide concrete decks Bridge Reichenbachtal Bridge Elben Bridge Schwarza Bridge Oehde 19 Bridge Wilde Gera 28,00m 2,00 10,00 1,50 1,50 10,00 2,00 5,50 5,50 transverse tension member longitudinal beams 35 3,15 5,00 1,20 3,80 3,80 1,20 5,00 3,15 35 Erfurt Schweinfurt 3,30 1,80 DB Wilde Gera 14, m

11 Bridge Wilde Gera 21 Bridge Wilde Gera Highway A71 transverse steel tension members transverse frames 22 11

12 Bridge Wilde Gera Highway A71 cantilever erection of the arch 23 Bridge Wilde Gera Highway A71 Bridge girder during launching 24 12

13 Bridge Albrechtsgraben - Highway A ,00 29,00 25,00 2,00 6,00 1,50 4,15 4,15 1,50 6,00 25 Bridge Albrechtsgraben - Highway A

14 Different detailing of transverse tension members 27 Joints between the longitudinal girders/box girders and the transverse tension members Bridge Albrechtsgraben Bridge Schwarza 28 14

15 Detailing of the transverse tension members D c A A Z s outside longitudinal girder Z s,q section A-A Z a Z s vertical stirrupps pulling down joint horizontal loops tension member 29 Acessment of different solutions for transverse tension members geometry of the concrete slab a constant depth of the slab over the total width of the bridge deck is required, uniaxial load transfer in transverse direction haunched concrete slab, expensive formwork, bi-axial load transfer in transverse and longitudinal direction slabs with constant depth and haunches in longitudinal direction are possible, uniaxial load transfer in transverse direction internal forces in the tension member high stresses due to local concentrated wheel loads (Fatigue resistance) higher stresses due to local loads. Resistance of the tension member to normal forces, bending moments and vertical shear should be considered no significant stresses in the steel tension member due to local loads connections economical simple connections with the top flanges of the box girder and the secondary longitudinal girders complicate connection caused by the eccentricity between the tension member and the top flanges of the box girder 30 15

16 Sequense of casting of concrete Method I : continuous in one direction 1 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 cross-section 28,50 70,0 70,0 7,5 7,5 3 x 15,0 17,5 7,5 3 x 15,0 17,5 7,5 3 x 15,0 3, Method I Method II Method III 31 bending moments acting on the composite section due to dead weight of concrete - M y = -105,3 M y = -103,2 M y = -107,5 - - Method I M y = -31,9 M y = -43,7 M y = -31, M y = 27,2 M y = 28,1 M y = -45,4 - + M y = 25,6 Method II M y = -32,5 M y = -33, M y = 26,5 M y = 27,3 M y = 25,4 Method III [M y in MNm] 32 16

17 Formwork carriage running on the top of the deck formwork carriage for cantilevers formwork tables on temporary consoles 33 Formwork carriage running on the top of the deck Bridge Wilde Gera 34 17

18 Formwork underneath the concrete deck formwork carriage for outer cantilevers formwork tables on temporary consoles Bridge Albrechtsgraben 35 Formwork underneath the concrete deck (system Kirchner) Bridge Schwarza 36 18

19 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. 37 Different possibilities for the exchange of the concrete slab A B exchange of one half of the deck exchange over a quarter of the bridge in two steps B 1 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. B 2 C exchange of one half of the deck with additional horizontal bracing Horizontal bracing 38 19

20 Bridge Oehde Freeway A ,8% 44,70 56,0 72,80 72,80 64,0 56,0 44,70 418,30 m ,5% Bridge Oehde Freeway A1 transverse tension member 40 20

21 Bridge Oehde Freeway A1 P1 P3 P2 P6 P4 P5 P9 P7 P8 P11 P10 P13 P12 P15 P14 concrete deck with partially prefabricated concrete elements launching of the bridge with partially prefabricated concrete elements 41 Composite bowstring arches Saalebridge Besedau 42 21

22 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. 43 Normal forces in the concrete tension member For the normal forces in the concrete member the effects of tension stiffening of concrete between cracks should be considered. The concrete member acts as a tension member in the main system. N= N s +N a ε s,2 ε s,m N a,2 N a = N a,2 -ΔN ts N N s= N s,2 + ΔN t,s N a N a = N a,2 -ΔN ts ΔN t,s N s N s,2 N s,cr N s,crn 44 22

23 Bridge Ladbergen near Ladbergen Highway A1 plan cross-section view end-bracing Detailing of composite bowstring arches 46 23

24 Composite trusses Bridge St. Kilian 47 Composite truss bridge with double composite action Bridge Nantenbach across the river Main C B C A 12,5 7 83,20m 208,00m 83,20m C 8 C A 9 10 B view 48 24

25 Composite truss bridge with double composite action Bridge Nantenbach across the river Main , , , ,00 1,40 R=2650,00m 1,00 1,20 1,40 R=2650,00m 1,00 1,40 3, , ,95 15,26 2,00 50 R=2650,00m 1,20 1,10-1, , ,60 2, ,60 2,60 1,60 49 Composite truss bridge Kragenhofer view 58,40 73,60 59,20 58,40 249, R= 1552, cross-section

26 Bridge St. Kilian 28,5 m 5,0 m 51 Bridge St. Kilian steel trusses with hollow sections and cast iron nodes 52 26

27 Composite bridges for small and medium spans Bridge Oberhartmannsreuth 53 Composite bridges with rolled sections for small an medium spans Advantages short construction time simple erection method because of no steelwork on site. steelwork only in the shop small total depth of the composite section concrete slab without any pre-stressing 54 27

28 Longitudinal reinforcement at internal supports L+l b b QRT L+l b concentrated shear connectors at the end of the girder l b -anchorage length of the reinforcement bottom layer of reinforcement A s,min = 16 a=10 cm The longitudinal reinforcement at internal supports should be placed over a length not smaller than L= 0,15 L St where L St 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. 55 Detailing of transverse supporting beams in concrete b min = 80cm (indirect support ) b min = 60 cm (direct support) b>b min b>90 cm 56 28

29 Detailing of partially prefabricated concrete elements C nom = 4,5cm 1,0 21 shear reinforcement mortar seal h c 4,0 2,5 3cm the depth of the concrete above the prefabricated elements h c should be not less than 20 cm within the traffic lanes. in other regions h c should not be less than 15 cm. 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. 57 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. 0,15 L casting of midspan regions L casting of supporting beams and the slab at internal support 58 29

30 VFT-Bridges with welded or rolled I-sections in situ concrete slab steel girder in the shop precasted concrete flange transport on site steel girder installation by crane 59 VFT-Filler beams 3200 rolled section 640 shear connection 60 30

31 VFT-Filler beams 61 Preflex - Beams steel girder prestressed composite 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

32 Preflex Girders pre-stressing of the concrete bottom flange δ campered steel girder F v F v pre-stressing forces F v applied to the steel girder (elastic bending) F v F v F v F v casting of the concrete bottom flange removing of the prestressing force F v after hardening of concrete causes compressive stresses in the concrete bottom flange casting of the concrete top flange on site 63 Composite bridge with Preflex-Girders Hermann-Lieberum Bridge in Leipzig continuous beam, span 33 m and construction depth 130 cm 64 32

33 Cable stayed bridges 65 cable stayed bridge Wesel across the river Rhein ,24 64,554 64,554 64,554 64,554 64, ,82 61,76 396, ,412 D C 66 33

34 Cable stayed bridge Wesel across the river Rhein cross-section axes Cable stayed bridge Wesel across the river Rhein 3500 cross-section axes mm ,5% 2,5%

35 Joint between the steel and the concrete section concrete end cross girder joint with overlapping steel plates and headed studs concrete end cross girder 69 concrete end cross girder 70 35

36 Pylon in high strength concrete composite section +145,30m concrete section ,90 71 cables Use of parallel strand cables of galvanized waxed and PE-coated strands instead of traditionally used fully locked coil ropes

37 erection stages stages I and II stage III stages III to VIII stage IX 73 Canal bridges canal bridge Lippe 74 37

38 Canal bridge Magdeburg view 57,10 106,20m 57,10 6,30 10x5,71 10x5,31 10x5,31 10x5, ,81 cross-section 3,98 34,04 3,98 42,00 m 75 Canal bridge Magdeburg total length 228 m span length 57,1 m 106,2 m 57,1 m Structural steel t 76 38

39 Canal bridge Magdeburg transverse frame Launching of the bridge stage 2 stage 11 stage 17 stage

40 Canal-bridge Lippe 24,00m 24,80m 24,00m A B C D 4,75 28,00m 3,00 4,75 28,00m 3,00 +56,50 NW +56,50 NW 7,84 2,21 2,16 10,82 10,82 2,16 2,21 2,21 4,33 4,33 4,33 4,33 4,33 4,33 2,21 30,40m LT7 LT6 LT5 LT4 LT3 LT2 LT1 LT7 LT6 LT5 LT4 LT3 LT2 LT1 79 Canal-bridge Lippe 80 40

41 7 th Japanese German Bridge Colloquium Osaka 2007 Thank you very much for your attention 81 41