1. Senior Engineer, IDS Group Inc., 1 Peters Canyon Rd., Suite 140, Irvine, CA 92606.
2. Bruce G. Johnson Professor of Structural Engineering, ATLSS Center, Dept. of Civil and Environmental Engineering, Lehigh Univ., Bethlehem, PA 18015 (corresponding author).
3. Joseph T. Stuart Professor of Structural Engineering, ATLSS Center, Dept. of Civil and Environmental Engineering, Lehigh Univ., Bethlehem, PA 18015.