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Seminar on STRESS RIBBON BRIDGE

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Presentation on theme: "Seminar on STRESS RIBBON BRIDGE"— Presentation transcript:

1 Seminar on STRESS RIBBON BRIDGE
Shreya Thusoo 10403EN006 IDD Part IV Department of Civil Engineering IIT (BHU), Varanasi

2 INTRODUCTION

3 Stress ribbon bridge: Modern analogy of ROPE BRIDGE

4 Stress Ribbon Bridge 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

5 STRUCTURE

6 Stress Ribbon Bridge Supports:

7 Stress Ribbon Bridge 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

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 Stress Ribbon Bridge 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.

10 Stress Ribbon Bridge Deck: Lake Hodges Bridge, USA

11 FABRICATION

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

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

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

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

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

17 Multi-spanned Bridges

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

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

20 Concluding notes

21 Stress Ribbon Bridge 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:

22 Stress Ribbon Bridge 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

23 World's longest stress ribbon bridge in Cuenca, Spain
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% World's longest stress ribbon bridge in Cuenca, Spain

24 Stress Ribbon Bridge Some important bridges in this category: Name
Country Main Span Rio Colorado Bridge Costa Rica 146 m Lake Hodges Bridge USA 100.9 m East Golf Cart Bridge 86.9 m Rogue River Pedestrian Bridge  84.73 m Aaresteg Mülimatt Switzerland 78 m Glacis Bridge  Germany 76 m Aaresteg Rupperswil 74.05 m Phyllis J. Tilley Memorial Bridge  49.5 m Kent Messenger Millennium Bridge United Kingdom 48 m Pùnt da Suransuns  40 m 1) 2) 3) 4) 5) 6) 7) 8) 9) 10)

25 Stress Ribbon Bridge Jiri Strasky Rogue River Pedestrian Bridge
Lake Hodges Bridge McLoughlin Boulevard Pedestrian Bridge West Golf Cart Bridge Jiri Strasky Sacramento River Trail Pedestrian Bridge West Golf Cart Bridge

26 Stress Ribbon Bridge References:
1) Strasky,J.- Stress-ribbon pedestrian bridges supported or suspended on arches. Brijuni Islands, 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

27 THANK YOU


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