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

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. 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. 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. Blast waves in air from
condensed high explosives
DETONATION
Gas expansion
⇓
Layer compressed air
⇓
blast wave
Remark :
overexpansion
⇓
reversal of flow

5. Blast wavefront parameters
Free air explosion

6. Blast Trials with Fuel Air explosions (Canada)
Defence R&D Canada – Suffield ♦ R&D pour la dēfense Canada - Suffield

7. TDM Blast Trials: 50 kg TBX
Defence R&D Canada – Suffield ♦ R&D pour la dēfense Canada - Suffield

8. Structural response to blast load
structural failure + dynamic problem

9. Resistance function
represents the load necessary to cause deflection
x x x x

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. 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. Special feature (1)
Internal explosions in car parks
- venting ⇒ pressure relief
- re – reflection of blast waves
- heat, fire
- gas pressure loading

13. Confined explosion
= series of impulses
+ quasi-static pressure

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. Near field explosions: crushing of concrete on
explosion side (spalling)

16. Near field explosions: scabbing effect on
tensile side

17. Explosion testing of in fil walls made of
cellular concrete blocs
28 Juin 2007

18. Spalling effect
on front side of
the wall

19. Scabbing effect on back side of the wall
Structural stability of wall is put in danger

20. Assessment of
structural
elements
Scaled RC
column
specimens for
near field
explosion testing

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. Tests on prototypes mixed steel
– concrete columns

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. 2D model: SPH processor
(Smooth Particle Hydrodynamics)

25. Numerical analysis :
hydro-dynamic behaviour of materials
Experimental test and model (Autodyn) of a mixed
steel – concrete column

26. Oklahoma-city : 2,4 Tons TNT
equivalent

27. Failure in punching shear
Importance of enhanced connections
between slabs and columns

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