1. Design Engineer, Olsson Associates, 2111 South 67th Street, Suite 200, Omaha, NE 68106.
2. Assistant Professor, Dept. of Civil Engineering, New Mexico State Univ., Las Cruces, NM 88003 (corresponding author).
3. Professor, Dept. of Civil Engineering, New Mexico State Univ., Las Cruces, NM 88003.
4. Associate Professor, Dept. of Civil Engineering, New Mexico State Univ., Las Cruces, NM 88003.