1. Department of Civil & Environmental Engineering, University of Yamanashi, 4-3-11, Takeda, Kofu, Yamanashi, 400-8511, Japan.
2. Department of Civil Engineering, Niigata University, 8050, Ikarashi Ninocho, Nishiku, Niigata, 950-2181, Japan.
3. Civil Engineering Research Laboratory, Central Research Institute of Electric Power Industry, 1646, Abiko, Chiba, 270-1194, Japan.