1. Postdoctoral Researcher, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706; Postdoctoral Researcher, Institute of Advanced Study, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka 8190395, Japan (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706.
3. Deceased March 1, 2013; formerly, Professor, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706.
4. Assistant Professor, Institute of Advanced Study, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.