Uncoupled analysis of Rc-slabs under near-field air explosions: Examination of various empirical equations for simulating blast loads

Document Type : Article

Authors

Department of Civil Engineering, Razi University, Kermanshah, 7149-67346, Iran

Abstract

In an uncoupled analysis, blast loads can be evaluated by empirical models, and then applied to the structure in a separate response analysis. The literature includes a variety of empirical models. However, the potentials of these models may not be fully realized due to a wide variation that may exist in their outcomes, particularly at detonations with a relatively close standoff distances from the target. As such, the selection of an appropriate model should be made with special considerations. This paper investigates the efficiency of various empirical models in blast analysis of the RC-slabs that are subjected to near-field air-detonations. The blast loads resulted by the empirical models are employed in a set of nonlinear FEA-runs. Due to the proximity of detonations, the distribution of blast-overpressure across the concrete slab at any instant in time is nonuniform. A simplified approach that accounts for this nonuniform distribution has been developed and verified in this study. To examine the effectiveness of the empirical models, the FEA-results are compared with the observations made in a set of previous experimental studies. Based on this comparative study, the most effective empirical model is identified, and remarks are made on the performance of the other models.

Keywords

Main Subjects

References

References:
1. Chang, J.I. and Lin, C.C. "A study of storage tank accidents", Loss Prevention in the Process Industries, 19(1), pp. 51-59 (2006).
2. Zhou, X.Q., Kuznetsov, V.A., Hao, H., and Waschl, J. "Numerical prediction of concrete slab response to blast loading", Int. J. Impact. Eng., 35, pp. 1188-1200 (2008).
3. Tai, Y.S., Chu, T.L., Hu, H.T., and Wu, J.Y. "Dynamic response of a reinforced concrete slab subjected to air blast load", Theor. Appl. Fract. Mec., 56, pp. 140-147 (2011).
4. Zhao, C.F. and Chen, J.Y. "Damage mechanism and mode of square reinforced concrete slab subjected to blast loading", Theor. Appl. Fract. Mec., 63-64, pp. 54-62 (2013).
5. Wang, W., Zhang, D., Lu, F., Wang, S., and Tang, F. "Experimental study and numerical simulation of the damage mode of a square reinforced concrete slab under close-in explosion", Eng. Fail. Anal., 27, pp. 41- 51 (2013).
6. Li, J. and Hao, H. "Numerical study of concrete spall damage to blast loads", Int. J. Impact. Eng., 68, pp. 41-55 (2014).
7. Koneshwaran, S., Thambiratnam, D.P., and Gallage, C. "Response of segmented bored transit tunnels to surface blast", Adv. Eng. Softw., 89, pp. 77-89 (2015).
8. UFC 3-340-02 "Structures to resist the effects of accidental explosions", Unified Facilities Criteria, US Department of Defense, Washington DC (2009).
9. Mays, G.C. and Smith, P.D., Blast Effects on Buildings, Thomas Telford Services Ltd, 1 Heron Quay, London (1995).
10. Flynn, P.D. "Elastic response of simple structures to pulse loading", Ballistics Research Laboratory, Aberdeen Proving Ground, Maryland, USA, BRl Memo Report No. 525 (1950).
11. Brode, H.L. "Numerical solutions of spherical blast waves", J. App. Phys., 26(6), pp. 766-775 (1955).
12. Ethridge, N.M. "Blast effects on simple objects and military vehicles II operation SUN BEAM", US Army Armament Research and Development Center, Ballistics Research laboratory, Aberdeen Proving Ground, Maryland, USA, Project 1.3, POR-2261 (1964).
13. Dewe, J.M. "The air velocity in blast waves from T.N.T. explosions", Proc. Roy. Soc. Lond., A 279(1378), pp. 366-385 (1964).
14. Friedlander, F.G. "The diffraction of sound pulses. I. Diffraction by a semi-infinite plate", Proc. Roy. Soc. Lond., A 186(1006), pp. 322-344 (1946).
15. Baker, W., Explosions in Air, University of Texas Press, Austin, USA (1973).
16. Kinney, G.F. and Graham K.J., Explosive Shocks in Air, Springer, Berlin (1985).
17. Rankine, W.J.M. "On the thermodynamic theory of waves of finite longitudinal disturbance", Phil. Trans. Roy. Soc. Lond., 160, pp. 287-288 (1870).
18. Henrych, J., The Dynamics of Explosion and Its Use, Elsevier, Amsterdam (1979).
19. Sadovskiy, M.A. "Mechanical effects of air shock waves from explosions according to experiments", in: M.A. Sadovskiy Selected Works: Geophysics and Physics of Explosion, Nauka press, Moscow (2004).
20. Michael, M. and Swisdak, J.R., Simplified Kingery Air Blast Calculations, Naval Surface Warfare Center, Indian Head Division (1994).
21. Wu, C., Oehlersa, D.J. Rebentrostb, M. Leachc, J., and Whittakerd, A.S. "Blast testing of ultra-high performance fiber and FRP-retrofitted concrete slabs", Eng. Struct., 31, pp. 2060-2069 (2009).
22. Wang, W., Zhang, D., Lu, F., Wang, S., and Tang, F. "Experimental study on scaling the explosion resistance of a one-way square reinforced concrete slab under a close-in blast loading", Int. J. Impact. Eng., 49, pp. 158-164 (2012).
23. AUTODYN, Theory Manual, Century Dynamics (2006).
24. LS-DYNA V971, Keyword Manual, 1 and 2. Livermore, CA: Livermore Software Technology Corporations (2009).
25. Thiagarajan, G., Kadambi, A.V., Robert, S., and Johnson, C.F. "Experimental and finite element analysis of doubly reinforced concrete slabs subjected to blast loads", Int. J. Impact. Eng., 75, pp. 162-173 (2015).
26. Riedel, W., Thoma, K., and Hiermaier, S. "Numerical analysis using a new macroscopic concrete model for hydro codes", In Proc. of 9th International Symposium on Interaction of the Effects of Munitions with Structures, Berlin, Germany, pp. 315-322 (1999).
27. Herrmann, W. "Constitutive equation for the dynamic compaction of ductile porous materials", J. Appl. Phys., 40, pp. 2490-2499 (1969).
28. Tu, Z.G. and Lu, Y. "Evaluation of typical concrete material models used in hydro codes for high dynamic response simulations", Int. J. Impact. Eng., 36(1), pp. 132-146 (2009).
29. Johnson, G.R. and Cook, W.H. "A constitutive model and data for metals subjected to large strains, high strain rates and high  temperatures", In Proc. of the Seventh International Symposium on Ballistics, Hague, Netherlands, pp. 541-548 (1983).
30. Newmark, N.M. and Hansen, R.J. "Design of blast resistant structures", Shock and Vibration Handbook, 3, Harris and Crede, Eds. McGraw-Hill, New York, USA (1961). 
31. Held, M. "Blast waves in free air", Propellants, Explosives, Pyrotechnics, 8(1), pp. 1-8 (1983).
32. Mills, C.A. "The design of concrete structure to resist explosions and weapon effects", In Proc. the 1st Int. Conference on Concrete for Hazard Protections, Edinburgh, UK, pp. 61-73 (1987).
33. Bajic, Z. "Determination of TNT equivalent for various explosives", Master's Thesis, University of Belgrade, Belgrade (2007).
Scientia Iranica
Volume 26, Issue 2 - Serial Number 2
Transactions on Civil Engineering (A)
March and April 2019
Pages 650-666

Files

Share

How to cite

Statistics