1. Assistant Professor, Dept. of Civil and Environmental Engineering, Louisiana State Univ. and A&M College, 3531 Patrick F. Taylor Hall, Nicholson Extension, Baton Rouge, LA 70803.
2. Associate Professor, School of Architecture and Civil Engineering, Xiamen Univ., Xiamen, Fujian, People's Republic of China; formerly, Postdoctoral Researcher, Dept. of Structural Engineering, Univ. of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0085 (corresponding author).
3. Professor, Dept. of Structural Engineering, Univ. of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0085.