1. Associate Professor, Dept. of Architecture and Building Engineering, Tokyo Institute of Technology, M1-29, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan. E-mail: ttoru@arch.titech.ac.jp
2. Graduate Student, Dept. of Architecture and Building Engineering, Tokyo Institute of Technology, M1-29, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan.
3. Associate Professor, Structural Engineering Research Center, Tokyo Institute of Technology, 4259 Nagatsuda, Midori-ku, Yokohama-shi, Kanagawa 226-8503, Japan.
4. Manager, Building Materials and Engineering Service Dept., Nippon Steel Corporation, Ohtemachi 2-6-3, Chiyoda-ku, Tokyo 100-8071, Japan.