Assessment of the perforation limit of a composite RC barrier with a rear steel liner to impact of a non-deforming projectile

An important aspect in the design of protective structures is minimization of the spalling phenomena at the protected faces of its walls. One way to solve this design aspect is to attach a protective sheet, commonly made of steel, to the rear face of a protective barrier. This paper proposes a model to assess the perforation resistance of a composite RC barrier with a rear steel liner to impact of a non-deforming projectile. The model uses an integration of existing perforation models for steel and for concrete and it shows very good agreement with available experimental results. The proposed calculation procedure enables evaluation of a concrete thickness reduction factor of a composite barrier compared to a bare RC barrier. It also enables examination of alternative design solutions according to the various resistance levels that are predicted by the model. For example, it is also shown that the thickness ratio, with-to-without steel liner, is hardly influenced by the concrete strength (which does affect the absolute perforation thickness).