Norwegian Timber Bridges: Current Trends and Future Directions Erik Aasheim

Transcription

1 Norwegian Timber Bridges: Current Trends and Future Directions Erik Aasheim

2 Topic areas Basis for timber bridge construction Typical construction elements Protection measures Possibilities in design and shaping Monitoring of timber bridges Examples of recent timber bridges Future directions

3 Basis for timber bridge construction

4 Traditions in use of timber More than 900 years old stave churches, 30 of them still standing

5 Viking ships

6 Log houses

7 Old Dønfoss Bridge (1896)

8 Gjelten Bridge 1906

9 Kveberg Bridge 1906

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13 Nordic Timber Bridge Program First meeting: May 7, 1993 FPL, Madison WI, USA

14 Nordic Timber Bridge Program The main objective was to increase the competitiveness of timber bridges compared with other materials like steel and concrete.

15 Nordic Timber Bridge Program Timber industries/road authorities 50 % Nordic Industrial Fund Nordic Wood 30 % National research funds 20 %

16 Nordic Timber Bridge Program technical reports 3 brochures (presentation of Nordic timber bridges) Background knowledge for new timber bridges

17 Why build timber bridges today? Economy: Widened range of construction materials increased competition Aesthetics: New possibilities in design and shaping Environment: - Low energy consumption - CO2-bonding not emission - Renewable material

18 Keywords in the Design of Norwegian Timber Bridges: Simplicity Robustness Durability Aesthetics

19 Confidence in wood as a bridge construction material: Loadbearing structure in glulam Bridge deck in stress laminated timber and beyond that: > Wood where wood is advantageous > Steel where steel is advantageous > Concrete where concrete is advantageous

20 Typical construction elements

21 Typical construction elements in modern Norwegian timber bridges Glued laminated members Stress laminated timber decks Slotted-in steel plates Steel cross girders

22 Three typical construction elements Steel cross girders Stress laminated timber deck

23 Typical construction elements Stress laminated timber deck with prestressing rods

24 Example of slotted-in steel plates Truss with glulam members jointed with slotted-in steel plates

25 Example of slotted-in steel plates Truss with glulam members jointed with slotted-in steel plates

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27 Protection measures

28 Protection measures when aiming at 100 years service life Pressure treatment with Creosote Copper cladding on exposed surfaces Liquid bitumen membrane on stress laminated timber deck Careful detailing with respect to water traps

29 Cross section of pressure treated glulam Light creosote treatment with sapwood not fully penetrated

30 Protection of exposed surfaces by copper cladding Tynset Bridge (2001)

31 Protection of exposed surfaces by copper cladding Tynset Bridge (2001)

32 Weather protection of large arches Louvre of wood Horne Bridge (2002)

33 Louvre of wood

34 Protected by the bridge deck

35 Protected by a roof

36 Possibilities in design and shaping

37 New possibilities in design and shaping Leonardo da Vinci Bridge (2001)

38 Glulam arch cross-section before grinding Leonardo da Vinci Bridge (2001)

39 Grinding of glulam arches Leonardo da Vinci Bridge (2001)

40 Erection of glulam arches Leonardo da Vinci Bridge (2001)

41 Assembly completed Leonardo da Vinci Bridge (2001)

42 Curved, stress laminated decks Deck built up of two by two lamellas, glued together in bent condition

43 Monitoring of timber bridges

44 Objects of the instrumentation Wood moisture content (MC): - stress laminated deck - load bearing structure Prestressing force: - stress laminated deck Structural dilatation: - stress laminated deck - load bearing structure 44

45 Typical instrumentation layout 45

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47 Instruments Vaisala Humitter 223 mm 20 mm 120 mm Rubber sealant Plastic tube Connection box

48 Instruments Load cell Hottinger CR 6

49 120 kn 115 Bar forces Bar 15 Bar 16 Bar Restressing Apr May Jul Aug Oct Sep Aug Jun May Apr Mar Feb Dec Nov Oct Sep 2003 Date 19 Nov 2004

50 Ambient climate at Evenstad Bridge 50

51 Evenstad Bridge MC trend 51

52 Examples of footbridges

53 Os Footbridge (1996) Covered truss bridge, spans 2 x 40 m

54 Sellikdalen Footbridge (2009) Covered truss bridge Spans m Total length 102 m

55 Klemetsrud Footbridge (2005) Main span 45,0 m total length 158,1 m

56

57 Nesoddveien Footbridge (1999) Truss bridge with span 24 m

58 Måna Footbridge (1999) King post bridge with span 24,1 m

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60 Kjærra Footbridge (1996) Footbridge with main span 92 m Polonceau truss in the middle part

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62 Leonardo Pedestrian Bridge (2001) Architects: Leonardo da Vinci and Vebjørn Sand

63 The Leonardo Bridge

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65 Examples of road bridges

66 Evenstad Bridge (1996) 5 spans of 36 m overall length 180 m

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70 Fønhus Bridge (1998) Span 35 m

71 Beston Bridge (1999) Span 20 m

72 Mattisdammen Bridge (2000) Span 7,2 m stress laminated slab made up of glulam beams

73 Tynset Bridge (2001) Main span 70 m overall length 124 m

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76 Daleråsen Bridge (2001) Spans 33 m and 27 m

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79 The old Flisa Bridge

80 The new Flisa Bridge concept Three span, Gerber system truss 7,3 53,6 16,7 16,7 38,4 7,3 70,3 56,0 55,2 196,0

81 Flisa Bridge (2003) Main span 70,3 m overall length 196 m

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85 Nybergsund Bridge (2005) 3 spans of 38,4 m total length 117 m

86 Nybergsund Bridge (2005)

87 Måsør Bridge (2005) Curved, span 50 m total length 83 m

88 Måsør Bridge (2005)

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90 Ner-Hole Bridge (2007)

91 Railway crossover bridge

92 Borlaug Bridge

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94 Finsveen Bridge (2006) Spans 6,9+9,0+6,9 m Total length 23,0 m

95 Kjøllsæter Bridge (2005) Combat vehicle bridge at Rena military camp Main span 45,0 m Total length 158,1 m

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99 Sletta Bridge (2011) Two spans of 23,0 m overall length 47,7 m

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101 Fjell-leet Bridge (2011) Span 44,4 m overall length 48,6 m

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103 Sundbyvegen Bridge (2011) Main span 42,0 m overall length 61,4 m

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105 Tretten Bridge (2012) Length 150 m

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107 Råde Bridge (Railway station) Span 19 m

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109 Future directions

110 Network arch bridge

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112 Timber bridge across lake Mjøsa Total length 1600 m

113 Large threaded rods New possibilities for effective joints

114 Project «Creosub» New protection technology to substitute creosote for protection of railway sleepers, timber bridges and utility poles Consortium from Norway, Germany, Finland and United Kingdom Duration: Industries, universities and institutes

115 Thanks to representatives from: Norwegian Public Roads Administration Norwegian consulting companies Norwegian architects Norwegian timber industries for their contributions to this presentation!

116 Thank you for your attention!