ABSTRACT
In recent years, the steel pipe pile with extended spiral plate (hereinafter referred as the steel spiral pile) is one of typical pile foundation systems in several construction fields in Japan. First in the late 1970’, it has been developed as a small sized pile system mainly for housing or residential buildings. Now this kind of pile system has developed its size variation (100 mm to over 1500 mm) and the pile installation technique, came to be the indispensable option for the selection of foundation specifications.
