Punching of high strength concrete flat slabs without shear reinforcement

• The use of a HSC (fc = 130 MPa) resulted in a punching capacity increase of 42%.
• MC2010 provides better punching capacity predictions using the real aggregate size.
• EC2 provides predicted punching capacity close to those obtained experimentally.

The experimental research carried out to study the punching behavior of high strength concrete (HSC) flat slabs is reported in the present work. Three flat slab specimens were cast using HSC and another one with normal strength concrete (NSC), to be used as a reference slab. The HSC mix presented a compressive strength of about 130 MPa, with a basalt coarse aggregate. The tested specimens were square with 1650 mm side and 125 mm thickness. The longitudinal reinforcement ratio varied between 0.94% and 1.48%.The experimental results show that the use of HSC led to a significant load capacity increase when compared with the reference model made with NSC. Furthermore, the experimental results also indicated that as the longitudinal reinforcement ratio increased, the punching capacity also increased. The results obtained in this set of experimental tests and others collected from the literature were compared with the code provisions by EC2, MC2010 and ACI 318-11.