1. Postdoctoral Scholar, Dept. of Mechanical and Civil Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125; formerly, Ph.D. Candidate, Dept. of Structural Engineering, Univ. of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0085.
2. Assistant Professor, Faculty of Engineering and Applied Sciences, Univ. of Los Andes, Mons. Alvaro del Portillo, Las Condes 12455, Santiago, Chile; formerly, Ph.D. Candidate, Dept. of Structural Engineering, Univ. of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0085.
3. Professor, Dept. of Structural Engineering, Univ. of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0085 (corresponding author).
4. Professor, Dept. of Structural Engineering, Univ. of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0085.