[en] New penetration, scabbing and perforation formulae are derived for use in the deisgn of reinforced concrete barriers to withstand impact by hard missiles. This is done by using dimensional analysis together with physical theories for the various impact processes. This leads to impact formulae with unknown coefficients which are then determined by an analysis of all available test data. The new formulae so derived are simple and, because of their parametric formulation, have a range of applicability easily definable in terms of impact parameters. The analysis indicates that some recently proposed impact formulae are not safe from the point of view of barrier because the test data used for their derivation was affected by global movement of the barriers which reduced the measured local damage. (orig.)