This is an abridged presentation of a keynote talk delivered at IABSE conference, Istanbul, April 2023. My involvement in proposals for cutting edge, innovative structures and the need to regularly keep up to date and relevant for teaching and research means I am constantly looking at what is happening with major bridges worldwide. This has led to some thoughts on the future of major long span bridges, and asking the question ‘where next with long span bridges?’ This keynote paper condenses some past data on suspension and cables stay bridges, current influential bridges, and relevant data on other similar or relevant types of structure to start to answer this question from a practical viewpoint. It reviews the materials we use and looks at some recently proposed spans, it then looks at theoretical limits to spans and the forms these give to develop an answer to the question from an academic point of view. The consideration of long span bridges would not be complete without examining the effects of aerodynamics so some data is outlined with likely limits for future bridges. New considerations such as sustainability and carbon footprints are also considered to attempt to answer the question.

1. 10 May 2023
© Arcadis 2020 1
Dr David Collings
ARCADIS
University of Surrey

2. 10 May 2023
© Arcadis 2020 2
Where next with long
span bridges?
Dr David Collings
ARCADIS
University of Surrey

3. 10 May 2023
© Arcadis 2020 3
Where next with long
span bridges?
1.Past & Current Bridge data
2.Other Structures
3.Proposed Bridges
4.Theoretical Data
5.Aerodynamic Data
6.Carbon Emissions
7.Summary & Discussion

4. 1.Past & Current Data

5. Suspension bridges

6. 10 May 2023
© Arcadis 2020 6
Akashi Kaikyo Bridge 2005 1991m
明石海峡大橋

7. 10 May 2023
© Arcadis 2020 7
1915Çanakkale Bridge 2022 2023m
Currently the longest bridge span in the world

8. The growth is not smooth but jumps up
in steps and is related to:
Technology,
Failure,
Affordability,
Politics.

10. Cable stay bridges

11. 10 May 2023
© Arcadis 2020 11
Russky Bridge 2012 1104m

12. 10 May 2023
© Arcadis 2020 12
Changtai Yangtze Bridge 2021 1176m
长泰长江大桥

13. 10 May 2023
© Arcadis 2020 13
Currently the longest cable stay bridge span

15. By 2100 cable stay and
suspension bridges
could be similar spans

16. 10 May 2023
© Arcadis 2020 16
Brooklyn Bridge 1883 486m
Uses stays

17. 10 May 2023
© Arcadis 2020 17
Yavuz Sultan Selim Bridge 2016 1408m
Uses stays

18. 10 May 2023
© Arcadis 2020 18
This hybrid cable stay-suspension form may be
a possible way forward for increased spans.

19. 10 May 2023
© Arcadis 2020 19
Oakland Bay Bridge, 1933 3x700m
Multi span bridges

20. © Arcadis 2015
Rion Antirion Bridge 2004 3x560m

21. © Arcadis 2015
Tai Zhou Bridge 台州大橋 2012 2x1080m

22. © Arcadis 2015
The multiple span bridges also show a possible
direction for long span bridges.

23. 10 May 2023
© Arcadis 2020 23
2.Other Data

24. 10 May 2023
© Arcadis 2020 24
Skyline 721
Longest Footbridge

25. 10 May 2023
© Arcadis 2020 25
Jais Flight - the longest zipline at 2,83km

26. 10 May 2023
© Arcadis 2020 26
Ameralik Fjord Powerline, 5.4km span

27. 10 May 2023
© Arcadis 2020 27
These other cable structures indicate
possible practical limits for long span
bridges.

28. 10 May 2023
© Arcadis 2020 28
1915Çanakkale Bridge Caisson

29. 10 May 2023
© Arcadis 2020 29
Changtai Bridge 45m 长泰长江大桥
1915Çanakkale Bridge 45m
Akashi Kaikyo Bridge 60m 明石海峡大橋
Rion Antirion Bridge 65m
Oakland Bay Bridge 74m
Tai Zhou Bridge 76m 台州大橋
Other Bridge Caissons

30. 10 May 2023
© Arcadis 2020 30
Troll A Platform 2014 300m

31. © Arcadis 2015
300m ………….
800m……..
1400m ……..
These deep-water structures show the depth
possible for the foundations of long span bridges.

32. 10 May 2023
© Arcadis 2020 32
Burj Khalifa 830m
哈里发塔
Towers

33. © Arcadis 2015
Buildings 高塔
Bridges 桥塔

34. © Arcadis 2015
These tower structures indicate possible practical
limits for long span bridge towers.

35. © Arcadis 2015
3. Proposed Spans 拟建大桥梁

36. © Arcadis 2015
Zhang Gao 张家港大橋 2.3km span

37. 10 May 2023
© Arcadis 2020 37
Messina Straights 3.3km span
墨西拿海峡大橋

38. 10 May 2023
© Arcadis 2020 38
Vartdalsfjorden, Sulafjorden and Sognefjord Fjords 2.2 to 3.7km span

39. © Arcadis 2015
Caspian crossing multiple 1.75km spans
里海大橋

40. © Arcadis 2015
These proposed bridges indicate possibilities for long
span bridges in the next decades.

41. © Arcadis 2015
4.Theoretical Data 理论桥梁结构

42. © Arcadis 2015
Radial 径向结构
Cable stay 斜拉桥 Suspension 悬索桥

43. © Arcadis 2015
Theoretical span limits: Span to height ratio
Radial 20km 2:1
Suspension 18km Tower height
Cable stay 15km 10km !

44. © Arcadis 2015
There are many assumptions used in the
theoretical calculations.

45. © Arcadis 2015
In practice many of the assumptions are not fully
met which can significantly affect the optimum
structural form and the span to height ratio.

46. Material quantities standard assumptions

47. © Arcadis 2015
Material quantities revised assumptions

48. © Arcadis 2015
The theoretical studies show possible directions and
limits for long span bridges

49. © Arcadis 2015
5.Aerodynamic Data
空气动力学

50. © Arcadis 2015
Truss or Box?
桁架桥还是箱梁桥？

51. © Arcadis 2015
Span to width
ratio important
Aerodynamically unstable
Aerodynamically stable

52. 10 May 2023
© Arcadis 2020 52
The effects of aerodynamics and in particular the
bridge width will remain a key influence on the
future development of long span bridges.

53. © Arcadis 2015
6.Carbon Emissions Data 碳足印

54. © Arcadis 2015
54
Data for normal bridges

55. © Arcadis 2015
The carbon content of a bridge increases
significantly as span increases.
Data for long span bridges

56. © Arcadis 2015
The carbon content of major bridges is likely to
be an important parameter for future bridges.

57. © Arcadis 2015
The hybrid cable stay-suspension form may be
a possible way forward for increased spans.
The multiple span bridges also show a possible
direction for long span bridges.
Truss or Box?
In Summary

58. © Arcadis 2015
Other cable structures indicate possible practical
limits for long span bridges.
.
Deep-water structures show the depth possible
for the foundations of long span bridges.
Tower structures indicate possible practical
limits for long span bridges.
The effects of aerodynamics and in particular
the bridge width will remain a key influence on
the future development of long span bridges.
In Summary

59. © Arcadis 2015
Theoretical studies show possible directions
and limits for long span bridges
The carbon content of major bridges is likely to
be an important parameter for future bridges.
These proposed bridges indicate possibilities for
long span bridges in the next decades.
In Summary

60. 10 May 2023
© Arcadis 2020 60
My thoughts based on
this data?
Cable stay and Suspension bridges similar spans before 2100.
Multi span bridges on deepwater foundations rather than extreme spans.

61. 10 May 2023
© Arcadis 2020 61
What are your thoughts?