Cover

The lid at the top of the manhole which can be removed when access to the interior of the manhole is required.

Cracks

Fracture lines visible around the circumference and/or along the length of a sewer.

Cradle

A structure constructed from concrete or masonry that provides structural support to a sewer. It typically surrounds the bottom and sides of a sewer up to the springing line.

Cradle Machine

A boring machine typically carried by another machine that uses winches to advance the casing.

Creep

The dimensional change, with time, of a material under continuously applied stress after the initial elastic deformation.