1. Members, ASCE
2. Student Member, ASCE
3. IMPACT Lab., DRB 101, Univ. of Southern California, Los Angeles, CA 91101.
4. U.S. Army Constr. Engrg. Res. Lab., P.O Box 9005, Champaign, IL 61820.
5. Dept. of Mech. and Aerospace Engrg., Univ. of California, Irvine, CA.