1. Senior Researcher, Steel Structures Research Laboratory, Steel Research Laboratories, Nippon Steel and Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu-city, Chiba 293-8511, Japan (corresponding author).
2. Head, Steel Structures Research Laboratory, Steel Research Laboratories, Nippon Steel and Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu-city, Chiba 293-8511, Japan.
3. Associate Professor, Dept. of Architecture and Building Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550, Japan.
4. Researcher, Steel Structures Research Laboratory, Steel Research Laboratories, Nippon Steel and Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu-city, Chiba 293-8511, Japan.
5. Senior Researcher, Steel Structures Research Laboratory, Steel Research Laboratories, Nippon Steel and Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu-city, Chiba 293-8511, Japan.