The paper extends the range of application of recently proposed criteria for the shear types of failure exhibited by reinforced concrete beams to the case of punching of flat slabs without shear reinforcement. Assuming that resistance to punching is mainly provided by two notional slab strips extending along the flexural reinforcement and intersecting each other at the head of the supporting column, the above failure criteria for reinforced concrete beams, which were derived within the context of the compressive force path theory from first principles without the need of calibration through the use of test data, are complemented with an expression defining the strip width. It is shown that through this addition, not only do the proposed criteria produce a closer fit to a wide range of test data than the formulae incorporated in current codes of practice, but also provide a better indication of the causes and location of punching initiation.
Gerasimos M. Kotsovos, Dipl Eng MSc PhD CEng
Michael D. Kotsovos, Dipl Eng DIC PhD DSc CEng