Research at structural concrete laboratory

Punching of concrete slabs

Research on punching shear is crucial, as it often controls the choice of the plate thickness in the design of flat slabs. Furthermore, the concequences of a punching failure are catastrophic, as demontrated by several accidents.
 
An important experimental research has been performed by the Structural Concrete Laboratory of EPFL, with more than 200 punching tests on full-size specimens since the year 2000. A mechanical model, the Critical Shear Crack Theory, has been developed. Initially applicable to symmetrical cases for slabs without transverse reinforcement, it has been expanded since and gives excellent results for all kinds of practical cases : slabs with transverse reinforcement, edge and corner columns, prestressed and post-tensioned slabs, fiber-reinforced concrete, strengthening of slabs, ...
 
Consequently, this model has been adopted by the Swiss Concrete Code SIA 262 (2003 and 2013) and by the fib 2010 Model-Code.
 

Reference publications

Theoretical model for symmetrical punching of slabs without transverse reinforcement

  • Muttoni A., Punching shear strength of reinforced concrete slabs without transverse reinforcement, ACI Structural Journal, Excel sheet, Vol. 106 N° 4, Farmington Hills, USA, 2008, pp. 485-494.
  • Theoretical model for symmetrical punching of slabs with transverse reinforcement

  • Fernández Ruiz M., Muttoni A. Applications of the critical shear crack theory to punching of R/C slabs with transverse reinforcement, ACI Structural Journal, Vol. 106 N° 4, Farmington Hills, USA, 2009, pp. 485-494.
  • Experimental investigation of slabs without punching reinforcement

  • Guandalini S., Burdet O., Muttoni A., Punching tests of slabs with low reinforcement ratios, ACI Structural Journal, V. 106, N°1, USA, 2009, pp. 87-95.
  • Experimental investigation of slabs with punching reinforcement

  • Einpaul J., Brantschen F., Fernández Ruiz M., Muttoni A., Performance of Punching Shear Reinforcement under Gravity Loading: Influence of Type and Detailing, ACI Structural Journal, V. 113, Farmington Hills, USA, 2016, pp. 827-838.
  • Lips S., Fernández Ruiz M., Muttoni A., Experimental Investigation on Punching Strength and Deformation Capacity of Shear-Reinforced Slabs, ACI Structural Journal, Vol. 109, USA, 2012, pp. 889-900.
  • Strengthening methods of slabs against punching

  • Fernández Ruiz M., Muttoni A., Kunz J., Strengthening of flat slabs against punching shear using post-installed shear reinforcement, ACI Structural Journal, V. 107 N° 4, USA, 2010, pp. 434-442.
  • Faria D. M. V., Einpaul J., P. Ramos A. M., Fernández Ruiz M., Muttoni A., On the efficiency of flat slabs strengthening against punching using externally bonded fibre reinforced polymers, Construction and Building Materials, Vol. 73, 2014, pp. 366-377.
  • Nonsymmetrical punching

  • Sagaseta J., Muttoni A., Fernández Ruiz M., Tassinari L., Non-axis-symmetrical punching shear around internal columns of RC slabs without transverse reinforcement, Magazine of Concrete Research, Paper 1000098, UK, 2011, 17 p.
  • Sagaseta J., Tassinari L., Fernández Ruiz M., Muttoni A., Punching of flat slabs supported on rectangular columns, Engineering Structures, 77, 2014, pp. 17-33.
  • Punching by seismic action

  • Drakatos I., Muttoni A., Beyer K. Internal slab-column connections under monotonic and cyclic imposed rotations, Engineering Structures, 123, 2016, pp. 501-516.
  • Influence of column size and slab slenderness

  • Einpaul J., Bujnak J, Fernández Ruiz M., Muttoni A., Study on Influence of Column Size and Slab Slenderness on Punching Strength, ACI Structural Journal, V. 113, Farmington Hills, USA, 2016, pp. 135-145.
  • Punching of fiber-reinforced concrete slabs

  • Maya Duque L. F., Fernández Ruiz M., Muttoni A., Foster S. J., Punching shear strength of steel fibre reinforced concrete slabs, Engineering Structures, Vol. 40, UK, 2012, pp. 93-94.
  • Punching of prestressed concrete slabs

  • Clément T., Pinho Ramos A., Fernández Ruiz M., Muttoni A, Influence of prestressing on the punching strength of post-tensionned slabs, Engineering Structures, Vol. 72, 2014, pp. 59-69
  • Clément T., Pinho Ramos A., Fernández Ruiz M., Muttoni A, Design for punching of prestressed concrete slabs, Structural Concrete 14 (2013), No. 2, pp. 157-167
  • Punching of continuous slabs

  • Einpaul J., Fernández Ruiz M., Muttoni A, Influence of moment redistribution and compressive membrane action on punching strength of flat slabs, Engineering Structures, Vol. 86, 2014, pp. 43-57
  • Einpaul J., Ospina C. E., Fernández Ruiz M., Muttoni A., Punching shear capacity of continuous slabs, ACI Structural Journal, Farmington Hills, USA, 2016, pp. 861-872
  • Punching of footings

  • Simoős J. T., Faria D. M. V., Fernández Ruiz M., Muttoni A., Strength of reinforced concrete footings without transverse reinforcement according to limit analysis, Engineering Structures, Vol. 112, 2016, pp. 146-161
  • Simőes J. T., Bujnak J., Fernández Ruiz M., Muttoni A., Punching shear tests on compact footings with uniform soil pressure, Structural Concrete, n° 4, 2016, pp. 603-617
  • Punching and slab-column connections subjected to very high column loads

  • Guidotti R., Fernández Ruiz M., Muttoni A., Crushing and Flexural Strength of Slab-Column Joints, Engineering structures, Vol. 33 n° 3, 2011, pp. 855-867.
  • Guidotti R., Fernández Ruiz M., Muttoni A., Durchstanzen von Flachdecken bei hohen Stützenlasten, Beton- und Stahlbetonbau, 105, Berlin, Germany, 2010, 19-26.
  • Slabs with concentrated loads in the vicinity of linear supports

  • Natário F., Fernández Ruiz M., Muttoni A., Shear strength of RC slabs under concentrated loads near clamped linear supports, Engineering structures 76, Vol. 72, 2014, pp. 10-23.
  • Vaz Rodrigues R., Fernández Ruiz M., Muttoni A., Shear strength of R/C bridge cantilever slabs, Engineering structures, Vol. 30, Netherlands, 2008, pp. 3024-3033.
  • Punching due to impact loading

  • Micallef K., Sagaseta J., Fernández Ruiz M., Muttoni A., Assessing punching shear failure in reinforced concrete flat slabs subjected to localised impact loading, International Journal of Impact Engineering, Vol. 71, 2014, pp. 17-33.
  • Codes

  • Muttoni A., Fernández Ruiz M., Bentz E. C., Foster S. J., Sigrist V., Background to the Model Code 2010 Shear Provisions - Part II Punching Shear, Structural Concrete, 2013.