Patent ID: 6484451
Filing Date: 2002-11-26
Classification: E02D

Abstract:
A stackable riser forming a passageway there through, comprising:a continuous side wall having an open first end portion facing in a first direction, an open second end portion facing in a second direction opposite from said first direction, an intermediate portion interconnecting said first and second end portions, and an inner surface and an outer surface; a shoulder on the outer surface of said side wall, said shoulder facing in said first direction and being spaced from said first end portion, wherein said outer surface includes a recess between said shoulder and said first end portion, said shoulder and said recess being shaped to receive the side wall of the second end portion of another riser; a channel on said second end portion, said channel being defined by said side wall and a middle wall member attached to said side wall, said middle wall member being spaced from said inner surface of said side wall, and said channel being shaped to receive a first end portion of another riser; and an anchor tab detachably attached to said outer surface of said side wall, said anchor tab protruding outwardly away from the riser and being adapted for being embedded in surrounding material.