Abstract
This paper describes the present situation of the use of high tensile strength steel in Japan for civil structures such as bridges, penstocks, water gates and storage tanks. In bridges where weight saving is especially needed, 490-570 N/mm2 class steel is used commonly and 690-780 N/mm2 class steel is used sometimes. On the other hand in energy facilities upon which high pressure acts, 780 N/mm2 class steel is used for penstocks and gas holders, 570 N/mm2 class steel for oil storage tanks, and 690 N/mm2 class (9% Ni) steel guaranteeing low temperature strength for liquefied natural gas storage tanks.