Composite concrete and plastic manhole system

摘要: A composite manhole unit comprising a plastic inner element and an outer skeletal frame made of structural material is provided. The fitted within the frame, leaving large sections exposed. exposed can be readily cut in field as necessary for attaching inlet outlet pipes. plurality units may combined assembled stacked manner to form system. pipe are sealed or connected each other water-tight while respective rest upon other. provides support excessive weight system reduced by using combination with element. protects from corrosive atmosphere within, example, sewer