Abstract: A bell and spigot joint of reinforced concrete manhole risers, or pipes, or abutting joints therein are improved by precasting the same, free or pre-cast grooves in the exterior faces intended for seating sealing rings. After pre-casting and curing in the kiln, the hardened, cured surfaces are machined to form a sealing ring groove proximate the ends thereof, for example around the spigot of a bell and spigot joint. The inside of the bell is also machined to hone the same to a smooth finish. The grooving apparatus is precisely centered on the axis of the member to produce a groove of uniform radius relative thereto.

Abstract: A pre-cast, reinforced concrete manhole riser is provided with a precisely aligned porthole for a sewer pipe, by cutting the hole on the site, the resulting smooth-faced, unobstructed porthole being sealed by a flexible collar having one end clamped on the pipe and having a flange at the other end adhered to the riser around the cut hole. Apparatus for cutting the hole, on the site, clamps on the upper rim of the riser, there being a cutter and carriage which move relative to a clamped frame.

Abstract: An underground joint between sewer pipe and reinforced concrete manhole riser is tightly sealed, and resistant to breakage caused by settling or frost heaving by a tapered, elastomeric, tubular connector boot, capable of flexing and yielding under lateral shift. A smooth faced hole is core drilled in the riser wall. The large end of the boot is expanded radially, by an expandable metal band, to a permanently enlarged diameter and internally clamped within the hole which compresses the material of the boot against the hole surface at 1000 psi, or more. The band is expanded and clamped in a direction normal to the central longitudinal axis of the sleeve by hydraulic jack means. The pipe end is inserted in the boot, up to the inside wall of the manhole, but is yieldable in any direction without leakage or breakage.