[1] Department of Civil Engineering, Faculty of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
[2] Nagasaki Shipyard and Machinery Works, Mitsubishi Heavy Industries, Ltd., 180 Akunoura-cho, Nagasaki, Japan
[3] Road Construction Division, Public Works Department, Nagasaki Prefectural Government, 2-13 Edo-machi, Nagasaki, Japan