1. Ph.D. Candidate, Civil and Environmental Engineering Dept., Univ. of California, Los Angeles, 5731 Boelter Hall, Los Angeles, CA 90095 (corresponding author).
2. Engineer, Exponent, 320 Goddard, Ste. 200, Irvine, CA 92618.
3. Researcher, Civil and Environmental Engineering Dept., Univ. of California, Los Angeles, 6679 Boelter Hall, Los Angeles, CA 90095.
4. Senior Bridge Engineer, Office of Earthquake Engineering, California Dept. of Transportation, 1801 30th St., Sacramento, CA 95816.
5. Professor, Civil and Environmental Engineering Dept., Univ. of California, Los Angeles, 5731 Boelter Hall, Los Angeles, CA 90095.