1. Research Fellow, Dept. of Structural Engineering, Building Research Institute, 1 Tachihara, Tsukuba City, Ibaraki 305-0802, Japan. E-mail: gongfa@kenken.go.jp
2. Dean, Faculty of Engineering and Surveying, The Univ. of Southern Queensland, Toowoomba QLD 4350, Australia. E-mail: bakerg@usq.edu.au