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Failures PowerPoint Presentation

Failures

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Failures

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  1. Failures

  2. The Ramsgate Walkway Collapse 1964 1994 6 killed 4 people died

  3. The Ramsgate Walkway Collapse

  4. The Ronan Point Collapse 1968 4 people killed Code of practice used : CP114 Structural Design of Reinforced Concrete Buildings

  5. Stability and robustness Buildings of this type can be very robust

  6. The Cleddau (Milford Haven) Bridge Collapse 1970 4 people died when the bridge collapsed under construction. The diaphragm above the pier buckled causing the then cantilevering section of the deck to collapse.

  7. The Cleddau (Milford Haven) Bridge Collapse 1970 At that time the use of finite element analysis was not well developed. Doing a shell element model with non-linear geometry and non-linear material behaviour would have been a major achievement. Nowadays it would be quite feasible and would certainly give warnings of the problem.

  8. Failures 4 deaths Charles de Gaulle Airport 2004 Main reason for the collapse: lack of ductility to resist dynamic punching shear

  9. Punching shear failure

  10. Failures Millennium Footbridge, London 2000 Synchronous lateral excitation

  11. Happened at night - no deaths The Hartford Connecticut Civic Center Roof Collapse 1978

  12. The Hartford Connecticut Civic Center Collapse Two major modelling errors were the main sources of this collapse. Second order effects (non-linear geometry) were important but not included in the model resulting in lower stiffness and higher internal forces than predicted.

  13. The Hartford Connecticut Civic Center Collapse Secondly the centroidal axes of the members were not coincident at the joints. This caused significant underestimates of moments in the members.

  14. Sleipner Platform before collapse - 1991 No deaths but very high financial loss

  15. Sleipner - Plan

  16. Sleipner - Mesh at Tricell

  17. Sleipner - Detail of Mesh at Tricell Junction

  18. Plan of tricell

  19. Pressure at 67 m depth: p = gh = 1000 x 9.81 x 67 = 66x 104 N/m Load on 1.0 m strip at 67 m depth: W = p x area = 66x 104 x 4.5 x 1.0 = 3000 x 103 N 3000 x 103 /2 = 1500 x 103 N Max shear:V = W/2 = Shear stress in concrete: vc = V/(bd) = 1500x103/(500x 1000) = 3 N/mm2 Maximum design shear stress (BS 8110 for unreinforced section): vc(BS8110) = 0.91 N/mm2 Calculation (checking model) for shear stress in tricell wall of Sleipner Platform Operating Conditions:Span of Wall - 4.5 m Effective depth - 500 mm, Pressure head 67.0 m

  20. Sleipner Collapse The collapse was due to the choice of an inadequate mesh of 3D elements for the walls of the tricells. The estimate of shear stress in the wall was about 1/3 of a realistic value. The computational model was not valid

  21. Hyatt Regency walkway collapse 1981 - 114 dead

  22. Hyatt Regency Error in understanding the load path for the hangers - Modelling error Fault in designer/contractor relationship Lack of robustness

  23. The Tay Bridge Disaster 1879 • Completed in February 1878. • Longest bridge in the world at time - 2 miles.

  24. View showing collapsed spans. 77 people killled • To date - worst structural accident in the British Isles.

  25. Pier No. 5 Looking North Lifting of windward column. (Dundee City Council, Central Library, Photographic Collection)

  26. THE END