1. Assistant Professor, Dept. of Civil Engineering, California State Univ., Chico, CA 95929 (corresponding author).
2. Assistant Professor, Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado, Boulder, CO 80309.
3. Professor, Dept. of Civil and Environmental Engineering, Stanford Univ., Stanford, CA 94305.
4. Engineer, Walter P. Moore and Associates, Inc., San Francisco, CA 94105.
5. Engineer, Quincy Engineering, Inc., Sacramento, CA 95827.