The present invention relates to a steel pipe pile head reinforcement structure in which a steel pipe pile is embedded in expanded foundation concrete to the length of the diameter of the steel pipe pile, and then an expanded foundation lower main reinforcement is installed in the longitudinal and transverse directions by penetrating a steel pipe pile through hole drilled to the height of the expanded foundation lower main reinforcement, and a horizontal reinforcing member is inserted and fastened into the through holes of two rows (layers) of steel pipe piles drilled between the cross-section of the steel pipe pile and the expanded foundation lower main reinforcement, thereby connecting the steel pipe pile and the expanded foundation to each other. More specifically, in the steel pipe pile head reinforcement structure for improved bending moment and uniform vertical load distribution, by inserting the steel pipe pile as much as the diameter of the steel pipe pile into the expanded foundation concrete, the bending moment and the transverse restraint effect of a steel pipe pile head joint are improved so that the joint between the steel pipe pile and the expanded foundation is completely fixed. In addition, by attaching the horizontal reinforcing member that is extended inside and outside the steel pipe pile, the composite effect and anti-slip bump (shear key) effect are maximized between the expanded foundation concrete surrounding the outer surface of the steel pipe pile and the steel pipe pile. The blocking effect (sum of the anti-slip effect and the composite effect) is maximized between a steel pipe pile body and the concrete filled inside a steel pipe pile cavity. In addition, the expanded foundation lower main reinforcement is completely integrated so that the vertical load of an upper structure can be evenly distributed to a steel pipe pile head and a steel pipe pile body.

본 발명은 강관말뚝 지름 길이만큼을 확대기초 콘크리트 속에 매입한 후, 확대기초 하부주철근 높이로 천공된 강관말뚝 관통홀을 관통하여 확대기초 하부주철근을 종방향 및 횡방향으로 설치하고, 강관말뚝 절단면과 확대기초 하부주철근 사이에 기 천공된 2열(층)의 강관말뚝의 관통홀에 수평보강재를 삽입 체결하여 강관말뚝과 확대기초를 서로 결합한 강관말뚝 두부보강 구조에 관한 것으로서, 보다 상세하게는, 강관말뚝 지름만큼을 확대기초 콘크리트 속에 삽입함으로써 강관말뚝 두부 결합부의 휨모멘트와 횡방향 구속효과가 향상되어 강관말뚝과 확대기초의 결합부가 완전 고정이 되고, 또한 강관말뚝 내/외부로 도출된 수평보강재를 부착함으로써 강관말뚝 외주면을 둘러싸고 있는 확대기초 콘크리트와 강관말뚝 사이에는 합성효과와 미끄럼방지턱(전단키) 효과가 극대화되고, 강관말뚝 본체와 강관말뚝 중공부 내부에 속채움한 콘크리트 사이에는 폐색효과(미끄럼방지턱효과와 합성효과의 합)가 극대화되며, 아울러 확대기초 하부주철근 배근이 완전히 일체화되어 상부구조물의 수직하중을 균등하게 강관말뚝 두부 및 강관말뚝 본체로 분포시킬 수 있는 구조로서 휨모멘트 향상과 균등한 수직하중분포를 위한 강관말뚝 두부보강구조에 관한 것이다.