Pipe Management Australia (PMA) was engaged by Unitywater to rehabilitate a maintenance hole located on a critical sewer rising main. Due to its function and exposure to continuous high-flow conditions, the structure had experienced concrete degradation and was assessed as requiring rehabilitation.
Client: Unitywater
Location: South East Queensland
Asset Type: Sewer Maintenance Hole (DN1500)
Solution: Panel Lok Maintenance Hole Lining System
Project Background
This maintenance hole formed part of a broader program of rehabilitation works delivered collaboratively between PMA and Unitywater, focused on extending asset life through innovative and trenchless solutions.
The Challenge
Maintenance holes located on rising mains are subject to constant hydraulic forces, turbulence and long-term exposure to aggressive sewer environments. Over time, this can result in severe concrete degradation and loss of structural integrity.
Key challenges on this project included:
- Critical asset location on a live rising main, requiring active monitoring of upstream pump station
- Large diameter structure (DN1500)
- Busy roadside environment, multiple roads meeting at a roundabout, requiring traffic control and night works
- Significant depth, requiring confined space and working at heights procedures
- Weather impacts, including periods of heavy rain
- Existing fence constructed over the maintenance hole, requiring removal and reinstatement
Unitywater required a solution that could be delivered safely, efficiently, and with minimal disruption to surrounding infrastructure.
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The PMA Solution
PMA was awarded the project based on its innovative approach and collaborative engagement with the asset owner to develop improved methodologies for maintenance hole rehabilitation.
PMA proposed the use of its Panel Lok maintenance hole lining system, a structural lining solution designed to restore integrity and extend the service life of deteriorated structures.
Because the top of the maintenance hole was fully accessible, PMA was able to pre-construct the Panel Lok liner at its depot, allowing for rapid installation during planned night works and reducing time spent in confined space conditions on site.
Project Delivery
The works were delivered over five consecutive night shifts to minimise disruption and manage site constraints:
- Night 1 – Cleaning: High-pressure cleaning and surface preparation, utilising one of PMA’s advanced recycler units.
- Night 2 – Installation: Installation of the prefabricated Panel Lok liner.
- Night 3 – Grouting: Grouting of the annular space to achieve full structural rehabilitation.
- Night 4 – Benching: Benching was reformed and the cover slab applied.
- Night 5 – Fencing: Reinstatement of fencing around the maintenance hole and laying of turf.
Traffic control was implemented to manage the busy roadside location, with lighting used to safely support night operations. PMA crews adjusted work sequencing to accommodate periods of heavy rainfall while maintaining safety and quality outcomes.
Working at heights and confined space trained personnel and procedures were employed due to the depth of the maintenance hole.
The Outcome
Once the Panel Lok liner was installed, grout was injected to fill the annular space between the liner and the host asset, creating a structurally rehabilitated maintenance hole capable of withstanding ongoing rising main conditions.
PMA also coordinated the removal and reinstatement of the fence that had originally been constructed over the asset, ensuring the site was returned to its pre-works condition prior to project completion.
The project was delivered safely, efficiently and in close collaboration with Unitywater, demonstrating PMA’s ability to provide innovative rehabilitation solutions for complex, high-risk assets.
Key Benefits
The key benefits from this project include:
- Structural rehabilitation of a critical rising main maintenance hole
- Reduced time on site through off-site liner fabrication
- Improved safety by minimising working at heights and confined space exposure
- Minimal disruption through planned night works
- Collaborative delivery focused on innovation and asset longevity
By combining innovation, collaboration and proven rehabilitation systems, PMA delivered a safe, efficient and long-lasting outcome for Unitywater. The project reinforces PMA’s position as a trusted partner for the rehabilitation of critical sewer infrastructure.
Going Further with Maintenance Hole Rehab
PMA presented a White Paper called the Future is Fitted at No Dig 2025 in Melbourne. To explore more about the methodology, material selection considerations and project insights presented at No Dig 2025, download our Maintenance Hole Rehabilitation White Paper.
The paper unpacks the practical challenges facing ageing sewer and stormwater networks and outlines proven rehabilitation approaches delivered by Pipe Management Australia across the East Coast. Simply complete the short form above to have the white paper emailed directly to you.
