1. Ph.D. Candidate, College of Civil Engineering, Tongji Univ., 1239 Siping Rd., Shanghai 200092, China; Visiting Scholar, Univ. of Texas at Austin, 10100 Burnet Rd., Austin, TX 78758.
2. Professor, Associate Chair, and J. Neils Thompson Centennial Teaching Fellowship in Civil Engineering, Dept. of Civil, Architectural, and Environmental Engineering, Univ. of Texas at Austin, 10100 Burnet Rd., Austin, TX 78758 (corresponding author).