Cretex Pro-Ring™ Manhole Grade Adjustment Ring System

Project: MidCoast Council, Pro-Ring™ Installation in heavy traffic area, July 2022
Location: Whitbread St, located in road adjacent to Browns Creek Bridge, Taree NSW

The Problem, Failing MH and pavement

The Solution, Pro-Ring™ Grade adjustment rings

Background
This MH is located in the western side (North bound) lane in an industrial estate and is regularly impacted by heavy vehicles including large trucks and buses. The road had subsided approximately 50mm on the eastern side of the MH with the road surface and MH edge damaged and posing a safety hazard.
MidCoast Council selected ISC Services Pro-Ring™, a light weight, high strength grade adjustment ring manufactured from Expanded Polypropylene (ARPRO) that are specifically manufactured to raise manholes to surface level and are designed to withstand traffic loadings.

The failing pavement was saw cut and removed, exposing the manhole frame and pavers used to originally raise the MH to surface level. The frame and pavers were removed providing a clean and solid surface for the Pro-Ring™.

After checking the heights needed to match the road, council selected a single 4” Finish Ring which was installed using the M1 adhesive. A bead of M1 adhesive was also placed on top of the Finish Ring and a new heavy duty cover and frame was placed on top of the Pro-Ring™. Back filling and compaction was done prior to a cover of cold mix asphalt being placed and compacted with a plate compactor.

The road was opened immediately with heavy vehicles able to drive over the MH without delay.