Drainage structure forming method

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