MAN-HOLE Russian patent published in 2000 - IPC

FIELD: construction engineering. SUBSTANCE: this preferably relates to construction of water-supply and sewer man-holes. Man-hole has body, cover, and head-piece in the form of reinforced concrete slab with central through-hole and recesses in lower supporting surface. Slab rests on ground beyond body of man-hole. Recesses are made with internal surface in the form of truncated cone with its large base turned towards ground. Angle of incline of generating line towards lower base is 25-65 deg. Recesses are located in plan discretely over concentrically closed lines with their contour corresponding to external contour of lower surface of slab with distances L between axes of lines and distances f between axes of adjacent recesses on one line which are determined according to following relations: L = (1/8-1/4)r and f = (1/8-1/4)r, where r - minimal distance between external and internal contours of slab in plane of its lower surface. Height h of recesses is not larger than half of minimal height of slab. Application of aforesaid embodiment of man-hole allows for improving collaboration of system "slab - ground base", also strength and shear characteristics are improved with simultaneous simplification of production. EFFECT: higher efficiency. 6 dwg