MULTI-DIRECTIONAL X-SHAPED BAR ARRANGEMENT REINFORCED CAST-IN-PLACE CONCRETE PILE PARTIALLY COATED WITH STEEL PIPE

摘要

PROBLEM TO BE SOLVED: To provide a multi-directional X-shaped bar arrangement reinforced cast-in-place concrete pile partially coated with a steel pipe by promoting the ductility of the cast-in-place concrete pile to give an excellent earthquake resistance and, at the same time, having good construction efficiency capable of maintaining bearing strength of vertical load even in a limited state. SOLUTION: A multi-directional X-shaped bar arrangement core body 2 having the length H of an X-shaped plane of structure longer than 3/4 of the length L up to a first inflection point in a shear distribution of the pile head calculated by study of pile body stress to horizontal force in the case of earthquake and set under the length L up to the first inflection point is buried in a concrete 1 of the pile head section in a cast-in-place concrete pile. A thin steel pipe 3 with smooth inside and outside surfaces and having an axial length (h) shorter than the length H of the X-shaped plane of structure is buried in a place with large bending moment caused by horizontal force in the case of earthquake to constituted a multi-directional X-shaped bar arrangement reinforced cast-in-place concrete pile partially coated with the steel pipe.