These slides present an introduction to Stress-Ribbon Bridges, an innovative bridge design which is aesthetic and easy to fabricate.

1. Shreya Thusoo
10403EN006
IDD Part IV
Department of Civil Engineering
IIT (BHU), Varanasi

3. Stress ribbon bridge: Modern analogy of ROPE BRIDGE

4. Features:
• Pedestrian bridges
• Highly stressed freely suspended pre-stressed tendons
• Precast or cast in situ deck slab
• Characterized by successive and complementary smooth curves
• Catenary shape or funicular shape
Stress Ribbon Bridge

6. Supports:
Stress Ribbon Bridge

7. Supports:
• Cables are pre-tensioned by anchoring into support structure, hence this
region is highly stressed.
• Performance may be improved by construction of:
i) flexible saddle
ii) parabolic haunch
iii) intermediate arch support
Stress Ribbon Bridge

8. Stress Ribbon Bridge
Simple support with constant section
Flexible saddle arrangement at support
Parabolic hunch arrangement at support
Stress ribbon supported by arch

9. Deck:
• Might be pre-fabricated or cast in-situ
• Stressed only by normal forces hence might be reduced by
waffles
• Integrated with end and intermediate supporting construction
so as to work as a composite structure.
Stress Ribbon Bridge

10. Deck:
Stress Ribbon Bridge
Lake Hodges Bridge, USA

12. Stress Ribbon Bridge
Leviation Stage:
I. Cables are hanged from supports
II. Pre cast segments are slided over the bearing tendons to desired position
III. Segments are jointed by cast in-situ composite slabs

13. Stress Ribbon Bridge
Leviation Stage:
Typical precast segment on bearing cables

14. Stress Ribbon Bridge
Leviation Stage:
Shifting of precast segment on bearing cables

15. Stress Ribbon Bridge
Basic Stage:
I. Static analysis is done at this stage.
II. After sufficient hardening of joints, post tensioning is done by pre-stressing
tendons.
III. Effect of dead load, creep, shrinkage, temperature and pre-stressing are
determined.
IV. Shape at this stage determines the final sag in the bridge.

16. Stress Ribbon Bridge
Service /Ultimate Stage:
Analysis of structure for all service loads is done

18. Stress Ribbon Bridge
These can be of following types:
(1)
Concrete or steel columns as intermediate supports

19. Stress Ribbon Bridge
(2)
Concrete arch as intermediate supports

21. Advantages:
• Minimal environmental and visual impact
• Can be erected without falsework or shoring
• Minimal long-term maintenance is required
• Are highly desirable at place as shown below:
Stress Ribbon Bridge

22. Disadvantages:
• Large horizontal forces at the end and intermediate which
determines economy of bridge.
Remedy- i) construction of flexible member close to
supports
ii) widening of deck at the ends
iii) having an arch shaped intermediate support
• Danger of overturning and oscillations due to high span to width
ratio.
Remedy- i) increasing sag
ii) proper dynamic analysis
Stress Ribbon Bridge

23. Recent advances:
Innovative design uses unidirectional
solid carbon fibre cables (TSC).
• Unsupported spans were
significantly increased
• Supporting structure was
reduced
• Installation time and cost
were reduced by over 80%
Stress Ribbon Bridge
World's longest stress ribbon bridge in
Cuenca, Spain

24. Some important bridges in this category:
Stress Ribbon Bridge
Name Country Main Span
Rio Colorado Bridge Costa Rica 146 m
Lake Hodges Bridge USA 100.9 m
East Golf Cart Bridge USA 86.9 m
Rogue River Pedestrian Bridge USA 84.73 m
Aaresteg Mülimatt Switzerland 78 m
Glacis Bridge Germany 76 m
Aaresteg Rupperswil Switzerland 74.05 m
Phyllis J. Tilley Memorial Bridge USA 49.5 m
Kent Messenger Millennium Bridge United Kingdom 48 m
Pùnt da Suransuns Switzerland 40 m
1)
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25. Stress Ribbon Bridge
Jiri Strasky
West Golf Cart Bridge
West Golf Cart Bridge
Sacramento River Trail
Pedestrian Bridge
Rogue River
Pedestrian Bridge
McLoughlin Boulevard
Pedestrian Bridge
Lake Hodges Bridge

26. Stress Ribbon Bridge
References:
1) Strasky,J.- Stress-ribbon pedestrian bridges supported or suspended on arches.
Brijuni Islands, 10-14 July 2008.
2) Strasky,J.: Precast stress ribbon pedestrian bridges in Czechoslovakia. PCI
JOURNAL, May-June 1987.
3) Strasky,J.: Stress-ribbon pedestrian bridges. International Bridge Conference.
Pittsburgh 1999.
4) Nakazawa, Tsutsumi, Yokota- Experimental study on dynamic characteristics of
Stress-Ribbon bridge. Ninth world Conference on Earthquake Engineering, JAPAN,
Aug 2-9, 1988.
5) Strasky,J.: Stress ribbon and cable supported Pedestrian bridges