If there are cable supports in joint lift manholes, what type of movement must be allowed?

The correct answer identifies that cable movement without stress must be allowed in joint lift manholes that have cable supports. This is crucial because cables need the ability to move freely to accommodate shifts caused by various factors, such as thermal expansion or ground settlement. If movement is restricted or if the cables are under stress, it could lead to damage or failure of the cables and the supporting structures.

Allowing movement without stress ensures that the cables can adjust to changes in their environment without experiencing tension or compression that could affect their integrity. This is particularly important in heavy highway construction, where equipment and heavy loads are subject to constant movement and environmental changes.

The other options would not be suitable in this context; allowing cable movement with stress could lead to problems under load, fixed movement would prevent necessary adjustments, and restricted movement would not provide the necessary flexibility to accommodate dynamic conditions, ultimately compromising safety and functionality.