DONG Guo-chao1, ZHANG Jian-ren1, CAI Chun-sheng1,2, HAN Yan1,LI Chun-guang1
(1. School of Civil Engineering and Architecture,Changsha Univ of Science and Technology, Changsha, Hunan410114,China;2. Dept of Civil and Environmental Engineering, Louisiana State Univ,Baton Rouge, USA LA70803)