Abstract
This paper describes a bearing capacity formula for steel pipe pile with four helical wings. The pile can be possessed high bearing capacity because of being screwed in with lateral soil displacement. 21 vertical loading tests, in which a new measuring system for axial strain of the pile was devised, were performed to evaluate the bearing capacity of these piles in various fields. A convenient bearing capacity formula, which is considered as a sum of end bearing capacity of the pile tip and four wings, is proposed based on the test results.
