TABLE I.* Empirical formulas for local response evaluation of reinforced
concrete targets (see Note 1).
(See Note 2)
50% of Rigid
- Modified NDRC
60% of Rigid
- Stone &
- Modified NDRC
70% of Rigid
- CEA - EDF
For a typical example using these empirical formulas and a discussion of their relative merits, please refer to
Section 3 of the technical support document (Reference 1) and Table A-1 therein. These formulas are not
applicable to unreinforced concrete or masonry structures.
The reduction factors for deformable missiles acknowledge the fact that they produce relatively less local
damage, and the impact forces do not exceed the crushing strength of these missiles. They are based on
recent aircraft engine missile tests and comparison of various empirical formulas and their agreement with the
actual test results, as reported by Sugano (Reference 5).
Penetration (x) is computed to determine t s and tp (Modified NDRC and Degen formulas only).
To prevent scabbing, minimum required thickness t
should be > 1.1 ts.
To prevent perforation, minimum required thickness t
should be > 1.2 tp.
Punching shear considerations for small nondeformable missiles are implicit in the formulas for penetration and
Recommended formula (see Section 126.96.36.199). References for all other formulas are given in Appendix C.
*All of the formulas presented in this table are based on data for lightly reinforced (0.3 percent - 1.5 percent each way)
concrete targets. Application to heavily reinforced targets would give a conservative estimate of local response.