Punching shear failure in blast-loaded RC slabs and panels

Abstract Reinforced concrete (RC) slabs and panels are commonly encountered in critical infrastructure and industrial facilities with a high risk of close-range explosions due to accidents or terrorist attacks. Close-in detonations lead to high intensity concentrated loads which can cause a premature brittle punching failure of the member. The assessment of such type of failure mode is challenging since the loading source varies its magnitude in space and time. This paper proposes an analytical method by which the occurrence of punching (or otherwise) is assessed by comparing the dynamic shear demand and capacity (supply). An exponentially decaying distribution of reflected overpressures on the RC surface is presented for this analysis. The punching shear demand is estimated from the pressure and inertial forces acting in the free-body diagram. The dynamic punching shear capacity is obtained using the Critical Shear Crack Theory with small slab deformations which are predicted from an equivalent single-degree-of-freedom model. The proposed approach takes into account the impulsive behaviour of the member leading to a higher punching capacity and provides better predictions than using existing formulae for punching which are based on tests with quasi-static loading and deformations. The proposed analytical equations are further supported by numerical explicit finite element models providing useful information of crack development, dynamic reactions and deflections. The application of the proposed method has been illustrated and validated by comparison with various tests with scale distances from 0.2 to 1.5 m/kg 1/3 . A practical example is presented to illustrate the applicability of the proposed method.

[1]  R. Clough,et al.  Dynamics Of Structures , 1975 .

[2]  A. Razaqpur,et al.  Blast loading response of reinforced concrete panels reinforced with externally bonded GFRP laminates , 2007 .

[3]  Gabi Ben-Dor,et al.  Full-scale field tests of concrete slabs subjected to blast loads , 2008 .

[4]  Tae-Hyung Lee,et al.  Probabilistic fiber element modeling of reinforced concrete structures , 2004 .

[5]  Andrew S. Whittaker,et al.  Air-Blast Effects on Structural Shapes of Finite Width , 2010 .

[6]  Colin M. Morison,et al.  Dynamic response of walls and slabs by single-degree-of-freedom analysis—a critical review and revision , 2006 .

[7]  Josef Hegger,et al.  Punching shear design of footings: critical review of different code provisions , 2014 .

[8]  Flavio Stochino,et al.  SDOF models for reinforced concrete beams under impulsive loads accounting for strain rate effects , 2014 .

[9]  Aurelio Muttoni,et al.  Non-axis-symmetrical punching shear around internal columns of RC slabs without transverse reinforcement , 2011 .

[10]  Pedro F. Silva,et al.  Improving the blast resistance capacity of RC slabs with innovative composite materials , 2007 .

[11]  Stephen R Reid,et al.  Inertia-sensitive impact energy-absorbing structures part II: Effect of strain rate , 1995 .

[12]  Jack P. Moehle,et al.  "BUILDING CODE REQUIREMENTS FOR STRUCTURAL CONCRETE (ACI 318-11) AND COMMENTARY" , 2011 .

[13]  Aurelio Muttoni,et al.  Punching shear strength of reinforced concrete slabs without transverse reinforcement , 2008 .

[14]  Wael W. El-Dakhakhni,et al.  Validity of SDOF Models for Analyzing Two-Way Reinforced Concrete Panels under Blast Loading , 2010 .

[15]  A. S. Fallah,et al.  On dimensionless loading parameters for close-in blasts , 2015 .

[16]  Sam D. Clarke,et al.  Experimental Studies of Blast Wave Development and Target Loading from Near-Field Spherical PETN Explosive Charges , 2015 .

[17]  Klaus Fischer,et al.  SDOF response model parameters from dynamic blast loading experiments , 2009 .

[18]  Gerald Nurick,et al.  The influence of boundary conditions on the loading of rectangular plates subjected to localised blast loading – Importance in numerical simulations , 2009 .

[19]  Wei Wang,et al.  Pressure-impulse diagram with multiple failure modes of one-way reinforced concrete slab under blast loading using SDOF method , 2013 .

[20]  Aurelio Muttoni,et al.  Punching shear strength of steel fibre reinforced concrete slabs , 2012 .

[21]  Anastasio P. Santos,et al.  Air blast resistance of full-scale slabs with different compositions: Numerical modeling and field validation , 2015 .

[22]  Franco Bontempi,et al.  Blast Resistance Assessment of Concrete Wall Panels: Experimental and Numerical Investigations , 2014 .

[23]  Pedro F. Silva,et al.  Retrofit for Blast-Resistant RC Slabs with Composite Materials , 2005 .

[24]  Andrew Tyas,et al.  Prediction of clearing effects in far-field blast loading of finite targets , 2011 .

[25]  Sam E. Rigby,et al.  Blast wave clearing effects on finite-sized targets subjected to explosive loads , 2014 .

[26]  Aurelio Muttoni,et al.  Applications of Critical Shear Crack Theory to Punching of Reinforced Concrete Slabs with Transverse Reinforcement , 2009 .

[27]  John M. Biggs,et al.  Introduction to Structural Dynamics , 1964 .

[28]  Andreas Leemann,et al.  Recycled aggregate concrete: Experimental shear resistance of slabs without shear reinforcement , 2012 .

[29]  Genevieve Langdon,et al.  Simulation of the response of fibre–metal laminates to localised blast loading , 2010 .

[30]  K. Prz.,et al.  Lehrhuch der Ballistik , 1912 .

[31]  J. Y. Chen,et al.  Damage mechanism and mode of square reinforced concrete slab subjected to blast loading , 2013 .

[32]  Gert Heshe,et al.  DS/ENV 1992-1-1 NAD. National Application Document for Eurocode 2: Design of Concrete Structures, Part 1-1: General Rules and Rules for Buildings , 1993 .

[33]  Guowei Ma,et al.  Influence of overall structural response on perforation of concrete targets , 2007 .

[34]  John Hetherington,et al.  Blast and ballistic loading of structures , 1994 .

[35]  Wei Wang,et al.  Experimental study on scaling the explosion resistance of a one-way square reinforced concrete slab under a close-in blast loading , 2012 .

[36]  Patrick F. Acosta,et al.  OVERVIEW OF UFC 3-340-02, STRUCTURES TO RESIST THE EFFECTS OF ACCIDENTAL EXPLOSIONS , 2011 .

[37]  Wei Wang,et al.  Experimental study and numerical simulation of the damage mode of a square reinforced concrete slab under close-in explosion , 2013 .

[38]  G. Nurick,et al.  The air-blast response of sandwich panels with composite face sheets and polymer foam cores: Experiments and predictions , 2013 .

[39]  Aurelio Muttoni,et al.  Assessing punching shear failure in reinforced concrete flat slabs subjected to localised impact loading , 2014 .

[40]  David Cormie,et al.  Blast Effects on Buildings , 2019 .

[41]  Duarte M. V. Faria,et al.  Strength of reinforced concrete footings without transverse reinforcement according to limit analysis , 2016 .

[42]  Jason Baird,et al.  Experimental and numerical analyses of long carbon fiber reinforced concrete panels exposed to blast loading , 2013 .

[43]  J. Mander,et al.  Theoretical stress strain model for confined concrete , 1988 .

[44]  Pedro F. Silva,et al.  Blast Resistance Capacity of Reinforced Concrete Slabs , 2009 .