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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 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 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 Composite Bridges with open and closed cross-sections Werra-Bridge Einhausen Typical cross-sections for composite bridges plate girder bridge with three rolled or welded main girders 16,75m 2,00 2,00 12,75m 25cm 2,5% cross-section with two separated box girders 45 cm 35 cm 2,575 5,80 45cm 2,575 5,80 35cm 2,5% 25cm box girder 55cm 3,00 40 cm 1,80 airtight welded box girders 25cm 6,80m 8,15m 4,30 3,00 7,15 1,80 2,5% 4,30 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 2875 1300 5700 mm 1300 2475 460 290 3,25 11,00 11,00 7000 mm 25,25 m Bridge Schleusetal Bridge Schleusetal transportation of steel girders on site erection of steel girders by cranes casting of the concrete deck by moveable formwork Examples for formwork systems formwork tables on temporary consoles retractable console rollers wedges scaffold beam formwork tables Bridge across the river Ruhr near Hagen-Freeway A1 1,96 1,50 1,50 14,50 1,25 3% 2,50 3,52 3,46 3,20 4,76 4,50 6,00 1,96 14,50 3% 3,01 2,50 concrete end cross girder cross-section at midspan cross-section at supports 2,50 3,52 6,00 2,50 3,01 35,06m 2,70 1,30 4,00m view 73,48m 95,77m 71,83m 10 Bridge across the river Ruhr near Hagen-Freeway A1 11 Bridge Neuötting -Double composite box girder 2.00 30.00 cross-section at support 11.50 3.00 11.50 0,34 0,52 2.00 3.75 concrete C35/45 6.92 3.75 cross-section at midspan 4.01 6.99 0,35 4.00 concrete C 50/60 95.00 3.30 3.30 7.00 3.30 7.00 3.30 HHW 366.00 4.36 3.30 6.23 4.39 362.00 154.00 68.00 58.00 470.00 12 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 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 2,25 14,50 1,75 1,50 cross-section 0,00 35 6% 40 4% 7,75 7,75 4% 15% 0,00 4% 6% 1,60 -2,95 3,35 5,90 5,90 18,50 3,35 3,35 5,65 5,65 3,60 18,25 15 Langerfelder Bridge – Highway A1 16 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 Composite box girders with wide concrete decks Bridge Reichenbachtal Bridge Elben Bridge Schwarza Bridge Oehde 19 Bridge Wilde Gera 28,00m 2,00 1,50 1,50 10,00 5,50 10,00 2,00 5,50 longitudinal beams transverse tension member 35 35 5,00 1,20 3,80 1,20 3,80 5,00 1,80 3,15 Schweinfurt 3,30 Erfurt 3,15 DB 14,50 Wilde Gera 30 36 42 42 42 42 42 252m 42 42 42 42 42 36 30 20 10 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 Longitudinal reinforcement at internal supports L+lb bQRT L+lb concentrated shear connectors at the end of the girder lb-anchorage length of the reinforcement bottom layer of reinforcement As,min = ∅16 a=10 cm 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 55 Detailing of transverse supporting beams in concrete bmin = 80cm (indirect support ) b>bmin b>90 cm bmin= 60 cm (direct support) 56 28 Detailing of partially prefabricated concrete elements mortar ≥Cnom = 4,5cm hc 4,0 2,5 1,0 21 shear reinforcement 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 seal ≥2,5 cm Elastomeric support strips with a thickness of cm and a width of 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 casting of supporting beams and the slab at internal support L 58 29 VFT-Bridges with welded or rolled I-sections in situ concrete slab precasted concrete flange steel girder steel girder in the shop transport on site installation by crane 59 VFT-Filler beams 3200 rolled section 640 shear connection 60 30 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 62 31 Preflex Girders – pre-stressing of the concrete bottom flange campered steel girder δ Fv Fv pre-stressing forces Fv applied to the steel girder (elastic bending) Fv Fv casting of the concrete bottom flange Fv Fv removing of the prestressing force Fv 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 Cable stayed bridges 65 cable stayed bridge Wesel across the river Rhein 10 20 30 40 53,24 64,554 64,554 64,554 60 50 64,554 64,554 396,132 D 80 70 334,82 90 61,76 376,412 C 66 33 Cable stayed bridge Wesel across the river Rhein cross-section axes 10 - 70 4250 550 700 6150 550 4250 2800 550 700 6150 400 550 67 Cable stayed bridge Wesel across the river Rhein cross-section axes 70 - 90 3500 8750 27500 mm 3000 8750 2,5% 7710 5900 3500 2,5% 2000 5900 7710 13800 68 34 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 Pylon in high strength concrete +145,30m composite section 3000 1000 4000 1000 3000 2000 concrete section 400 4000 500 3295-3971 +15,90 71 cables Use of parallel strand cables of galvanized waxed and PE-coated strands instead of traditionally used fully locked coil ropes 72 36 erection stages 70 10 80 90 stages I and II stage III stages III to VIII stage IX 73 Canal bridges canal bridge Lippe 74 37 Canal bridge Magdeburg view 57,10 106,20m 10x5,71 10x5,31 57,10 7,81 10x5,71 10x5,31 20 10 6,30 30 40 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 9.500 t 76 38 Canal bridge Magdeburg 1900 4819 1087.5 transverse frame 740 2440 740 77 Launching of the bridge stage stage 11 stage 17 stage 22 78 39 Canal-bridge Lippe 24,00m 24,80m A 24,00m B 28,00m 4,75 D C 3,00 4,75 3,00 28,00m +56,50 NW 7,84 +56,50 NW 2,21 2,21 2,16 LT7 10,82 LT6 LT5 10,82 LT4 LT3 2,16 2,21 LT2 4,33 LT7 4,33 LT6 4,33 4,33 30,40m LT5 LT4 4,33 4,33 LT3 LT2 2,21 LT1 LT1 79 Canal-bridge Lippe 80 40 7th Japanese – German Bridge Colloquium Osaka 2007 Thank you very much for your attention 81 41