Composite concrete and plastic manhole system

A manhole system comprised of a plurality of manhole units stacked upon one another;

• wherein each of the manhole units comprises:
• a rigid, skeletal, exterior frame having an inner surface;
• and
• an inner element comprising a corrosion resistant material and having an outer surface;
• wherein the inner element is positioned within the exterior frame such that the inner surface is adjacent to the outer surface.

A manhole unit, comprising:

• a rigid, skeletal, concrete, exterior frame having an inner surface;
• an inner element comprising a corrosion resistant material and having an outer surface;
• and
• wherein the inner element is positioned within the exterior frame such that the inner surface faces toward the outer surface.

A manhole unit, comprising:

• a rigid, skeletal, exterior frame having an inner surface, the exterior frame comprising a material selected from the group consisting of concrete, metal and combinations thereof;
• an inner element comprising a first corrosion resistant material and having an outer surface, the first corrosion resistant material comprising plastic;
• and
• wherein the inner element is positioned within the exterior frame such that the inner surface faces toward the outer surface.

A manhole unit, comprising:

• a rigid, skeletal, exterior frame having an inner surface;
• an inner element comprising a corrosion resistant material and having an outer surface;
• wherein the exterior frame includes a plurality of girders encircling the inner element and a plurality of columns connecting the plurality of girders, the plurality of girders comprising a top girder with a first joint protrusion and a bottom girder with a first mating joint, wherein the first mating joint is shaped to receive a second joint protrusion of a first adjacent manhole unit and the first joint protrusion is shaped to receive a second mating joint of a second adjacent manhole unit;
• and
• wherein the inner element is positioned within the exterior frame such that the inner surface faces toward the outer surface.

A manhole unit, comprising:

• a rigid, skeletal, exterior frame having an inner surface;
• an inner element comprising a first corrosion resistant material and having an outer surface;
• wherein the inner element is positioned within the exterior frame such that the inner surface faces toward the outer surface;
• and
• wherein the exterior frame is coated with a second corrosion resistant material.

A manhole unit, comprising:

• a rigid, skeletal, exterior frame having an inner surface;
• an inner element comprising a corrosion resistant material and having an outer surface;
• a locking system having a plurality of hollow protuberances projecting from the outer surface of the inner element and wherein the exterior frame at least partially fills the plurality of hollow protuberances;
• and
• wherein the inner element is positioned within the exterior frame such that the inner surface faces toward the outer surface.

A manhole system, comprising:

• a plurality of rigid, skeletal, exterior frames, each having an inner surface;
• an inner element comprising a corrosion resistant material and having an outer surface;
• wherein each of the plurality of rigid, exterior, skeletal, exterior frames includes a plurality of girders encircling the inner element and a plurality of columns connecting the plurality of girders, the plurality of girders comprising a top girder with a first joint protrusion and a bottom girder with a first mating joint, wherein the first mating joint is shaped to receive a second joint protrusion of a first adjacent manhole unit and the first joint protrusion is shaped to receive a second mating joint of a second adjacent manhole unit;
• and
• wherein the inner element is positioned within the plurality of rigid, skeletal, exterior frames such that the inner surface of each of the plurality of rigid, skeletal, exterior frames faces toward the outer surface of the inner element.

A manhole unit, comprising:

• a rigid, skeletal, exterior frame having a skeletal base and an inner surface;
• an inner element comprising a corrosion resistant material and having a base and an outer surface;
• wherein the exterior frame comprises a plurality of girders encircling the inner element and a plurality of columns connecting the plurality of girders, one of the plurality of girders being a top girder having a joint protrusion;
• and
• wherein the inner element is positioned within the exterior frame such that the inner surface faces toward the outer surface and the base of the inner element is adjacent to the skeletal base of the exterior frame.

A manhole unit, comprising:

• a rigid, skeletal, exterior frame having a skeletal base and an inner surface;
• an inner element comprising a corrosion resistant material and having a base and an outer surface;
• wherein the exterior frame comprises a plurality of girders encircling the inner element and a plurality of columns connecting the plurality of girders, one of the plurality of girders being a top girder having a mating joint;
• and
• wherein the inner element is positioned within the exterior frame such that the inner surface faces toward the outer surface and the base of the inner element is adjacent to the skeletal base of the exterior frame.