Abstract: An improved manhole concrete blockout for forming sewer pipe openings in the cast-concrete wall of a manhole where a hole is dug in the ground and at least one vertical hollow form is positioned within the hole and spaced apart from the surface which defines the hole and concrete is poured between the surface defining the hole and the form for forming a manhole wall. A plurality of form sections are connected together so that their outer surfaces can be positioned to become a longitudinal extension of the outer surface of the form. A blockout member is connected to the outer surface of at least one of the sections for forming an opening in the manhole wall, the end adjacent to the section being shaped to engage and conform to the outer surface of the section and the other end being shaped to conform to and engage the corresponding portion of the surface defining the hole so that an opening in the shape of the blockout member will extend through the wall when it is formed.

Abstract: A new and improved method for forming a drainage structure, such as a manhole for a subterranean sewer pipe. In a first embodiment, a removable outer form is positioned in an excavation in the earth extending to the sewer pipe so that the earth surrounding the sewer may be undercut and removed through the removable outer form. Concrete is poured into the undercut area surrounding the sewer pipe to a height adjacent the lower edge of the outer form and a second cylindrical inner form is positioned within the outer form so that concrete may be poured into the space between the forms to form upwardly extending wall portions to the surface. In a second embodiment, the outer form is positioned in an excavation at a predetermined location and a concrete base portion is formed. The inner form is positioned in the outer form and predetermined quantities of sand are poured into the space between the forms for facilitating connection with sewer pipes.