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UG_20090206_Vantomme

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Contribution of the Royal Militay Academy to the IWT SBO project on fire safety and explosion safety in car parks.

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UG_20090206_Vantomme

  1. 1. IWT – SBO project Fire safety in Car Parks Kick-Off meeting 06 February 2009 Contribution of Royal Military Academy John VANTOMME Fermin PASCUALENA ZABALZA Royal Military Academy Dept Civil and Materials Engineering
  2. 2. Koninklijke Militaire School - Ecole Royale Militaire Royal Military Academy, Brussels, Belgium www.rma.ac.be Bachelor Master Ma after Ma (Defence college) PhD (with civil universities)
  3. 3. RMA Polytechnical Faculty Civil and Materials Engineering Dept Teaching – Scientific research – Case studies in the fields of - Civil and mechanical engineering - Materials and structures - Effects of explosions on structures
  4. 4. Blast waves in air from condensed high explosives DETONATION Gas expansion ⇓ Layer compressed air ⇓ blast wave Remark : overexpansion ⇓ reversal of flow
  5. 5. Blast wavefront parameters Free air explosion
  6. 6. Blast Trials with Fuel Air explosions (Canada) Defence R&D Canada – Suffield ♦ R&D pour la dēfense Canada - Suffield
  7. 7. TDM Blast Trials: 50 kg TBX Defence R&D Canada – Suffield ♦ R&D pour la dēfense Canada - Suffield
  8. 8. Structural response to blast load structural failure + dynamic problem
  9. 9. Resistance function represents the load necessary to cause deflection x x x x
  10. 10. Structural response regimes T td impulsive regime td < 0,4 . T dynamic regime 0,4 . T < td < 2 . T quasi-static regime td > 2 . T
  11. 11. Research topics for parametric analysis of structural members Loads on structural elements: - detonation or deflagration (duration of load and change of rise time) Structural response without /with fire - Material laws : dynamic strengthening or fire modified behaviour - Composite action for global response of RC elements : - modification of elastic vibration response - plastic hinge accumulation - damage mechanisms
  12. 12. Special feature (1) Internal explosions in car parks - venting ⇒ pressure relief - re – reflection of blast waves - heat, fire - gas pressure loading
  13. 13. Confined explosion = series of impulses + quasi-static pressure
  14. 14. Special feature (2) Near field explosions - local blast overpressures > 10 bar (1000 kPa) - transmission and reflection of shock waves in solids (heated RC)
  15. 15. Near field explosions: crushing of concrete on explosion side (spalling)
  16. 16. Near field explosions: scabbing effect on tensile side
  17. 17. Explosion testing of in fil walls made of cellular concrete blocs 28 Juin 2007
  18. 18. Spalling effect on front side of the wall
  19. 19. Scabbing effect on back side of the wall Structural stability of wall is put in danger
  20. 20. Assessment of structural elements Scaled RC column specimens for near field explosion testing
  21. 21. Tests on prototypes of mixed steel – concrete columns Installation : Standing position + Compression effect Cannot tumble down Allows limited reflections on ground Sensors : Copper-crush cylinder Strain gauges
  22. 22. Tests on prototypes mixed steel – concrete columns
  23. 23. Modelling of blast behaviour of RC and mixed steel – concrete columns AUTODYN version 4.2.02a Century Dynamics Incorporated Hydrocodes : HYDROdynamic computer CODES
  24. 24. 2D model: SPH processor (Smooth Particle Hydrodynamics)
  25. 25. Numerical analysis : hydro-dynamic behaviour of materials Experimental test and model (Autodyn) of a mixed steel – concrete column
  26. 26. Oklahoma-city : 2,4 Tons TNT equivalent
  27. 27. Failure in punching shear Importance of enhanced connections between slabs and columns
  28. 28. Conclusion : RMA contribution to IWT SBO Fire project WP 1 : design for minimising fire and explosion risk: - parametric analysis of cause – consequence WP 2.1 : parametric analysis of structural members - slab and column: structural behaviour - the combination blast – fire - gas pressure - Analytical models - Numerical models: hydrocode (impact of material behaviour laws) WP 2.2 : Connections – punching shear - Real scale tests : fire with blast

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