Telescopic Cast Iron Frame Mean?
A telescopic cast iron frame is an installation in the manhole or storm drain that fits into its concrete structure. This frame makes adjustment to final asphalt easier, and less disruptive to the road surface. Trenchless rehabilitation techniques are non-disruptive to the road surface because the need to dig is eliminated.
However; for the purpose of rehabilitating manholes. the pavement around the manhole may be disrupted. A telescopic cast iron frame can eliminate that problem.
Trenchlesspedia Explains Telescopic Cast Iron Frame
A telescopic cast iron frame has an upper section with a riser assembly and a lower section with an inverted conical part and a vertical member with external threads that can screw on to a stationary threaded collar.
When a road has to be resurfaced, excavation around the riser is not required before it is elevated. The elevation is accomplished by means of a tool which engages mating receptors provided inside the riser. When the tool is rotated, the riser assembly rotates within the threaded collar until it reaches the desired elevation.
For non-circular upper sections, the riser is made of separate upper and lower sections with a sliding joint structure in between.