1. Dept. of Civil Engineering, Tianjin Univ., Tianjin 300072, China. E-mail: jwliang@tj.cnuninet.net
2. Postdoctoral Researcher, Dept. of Civil Engineering, Univ. of California, Irvine, CA 92697-2175. E-mail: samit@uci.edu
3. Distinguished Professor and Chair, Dept. of Civil and Environmental Engineering, Univ. of California, Irvine, CA 92697-2175. E-mail: shino@uci.edu