FITT Resources Taking an Innovative Approach to Manhole Repair and Refurbishment

At FITT Resources, we have been continually growing our capabilities in the areas of manhole replacement and refurbishment for both local councils and water industry operators across Australia. As part of this expansion, we are now utilising the Cretex Pro-Ring™ Manhole Grade Adjustment System, an innovative new process that reduces both costs and the time required to carry out manhole installation, repair and replacement in all types of locations.

How does the Pro-Ring™ System Work?

The Pro-Ring™ system features interlocking riser rings manufactured from Expanded Polypropylene (EPP) which are used to raise manhole frames to their final elevation. These rings, which can be either round or rectangular and are available in a variety of sizes, can be employed in place of traditional construction methods and materials, and have exceptional durability.

Different types of rings — Grade Rings, Finish Rings and Angle Rings — are used in a variety of configurations to meet the required manhole grade precisely, and this can be achieved without the need to use shims or packers, which can create weak points that cause leaks and early failure.

Pro-Ring™ manhole adjusters have an excellent strength-to-weight ratio and are watertight, yet at the same time the system is easy to assemble and install. This means that when manhole repairs are taking place in busy urban areas, disruption to traffic and pedestrian flow is kept to a minimum.

EPP is also chemical resistant and able to withstand repeated and heavy traffic impacts, meaning the Pro-Ring™ system provides long, cost-effective operating life.

Benefits of the Pro-Ring™ System for manhole replacement and installation

The Pro-Ring™ Manhole Grade Adjustment System delivers a number of significant benefits to Australian water industry operators.

The time required to refurbish or replace existing manholes, or to install new ones, is significantly reduced when employing the Pro-Ring™ system when compared to using concrete or other masonry materials. In addition, EPP does not deteriorate at the same rate as these conventional materials, and so it provides a longer operating life and reduces ongoing costs.

The costs of installing a new or replacement manhole are also significantly reduced when using the Pro-Ring™ manhole riser system. Less time and heavy duty equipment are required, meaning that a complete manhole replacement can in some cases be completed in a matter of hours. This reduces costs across the board, including those associated with having to restrict or redirect traffic flow in busy city and urban centres.

Pro-Ring™ meets Water Services Association of Australia standards

Independent testing has shown that Cretex Pro-Ring™ meets the new Water Services Association of Australia standard WSA-PS 345 pertaining to Polymeric Make-Up Rings for Sewerage Maintenance Holes, as well as the Class D load capacities set out in AS3996:2019 Access Covers and Grates.

Key Points:

• Testing performed on 36-24-600 Grade and Finish Rings
• Ultimate limit testing to 240kN (equivalent to 24,473 kg)
• Serviceability load testing to 160kN (equivalent to 16,315 kg)
• Fatigue testing over 300,000 cycles at 80kN (equivalent to 8,157 kg)
• Water tight and gas tight testing passed, both before and after load testing
• Ultimate limit and serviceability load tests were also repeated after fatigue testing and passed

Case Study : FITT Resources using Pro-Ring™ in Parkes, NSW

FITT Resources recently undertook the repair of 43 damaged sewer manholes for Parkes Shire Council in New South Wales. There were a variety of issues associated with these manholes, including the need to raise many of them back to surface level, old and damaged concrete lids that needed to be replaced, damaged frames, and water infiltration of low lying manholes.

28 of the manholes were located in roads and 15 off roads, and they typically needed to be raised by between 19mm (¾”) and 50mm (2”). Varying slopes and cambers also needed to be accommodated.

FITT Resources was able quickly and cost effectively to raise the lids to surface level, immediately backfill, reinstate the road surface, and then reopen the road to normal traffic with minimal disruption.

Firstly, existing lids and frames were removed using the Mr Manhole tool, which provides a clean, circular cut and complete removal of old or damaged components.

The Cretex Pro-Ring™ system then enabled our team to achieve the precise adjustments required without having to employ shims or packers, eliminating the possibility of these creating leaks. This was accomplished using a combination of Grade Rings, Finish Rings and Angle Rings. This was then followed by the installation of the new frame and lid, backfilling, and reinstatement of the road surface.

Roads where we undertook this work were able to be immediately re-opened, meaning the entire process was completed with minimal time required on site and less associated disruption of traffic than would otherwise have been the case.

Why did we choose Pro-Ring™?

FITT Resources selected the Cretex Pro-Ring™ manhole grade adjustment system supplied by ISC Services because it’s strong, yet lightweight and easy to install. When combined with the fact that it is able to withstand the high demands of traffic while providing a definite seal against infiltration, Crete Pro-Ring™ provides a more cost effective, long term solution to adjusting assets to meet grade for both new and rehabilitating structures.

Furthermore, Cretex Pro-Ring™ has been proof load tested to 50,000 lbs (22,679kg) and passes AASHTO M306 H25.

Find out more about Pro-Ring™

To find out more about the benefits of using Pro-Ring™ for manhole installation, repair and replacement, contact Richard Arthur in our Water Industry Services Division on 0404 993 806, or email r.arthur@fittresources.com.au. You can also see more of our complete range of services for the Australian water industry here.