GRP Maintenance Shafts (PermaManhole)
GRP maintenance shafts and manhole liners with faster installation, superior corrosion resistance and significantly longer service life than concrete.
For decades, concrete was the default. Today, RPC’s GRP (Glass Reinforced Polymer) maintenance shafts are transforming the industry with faster installation, superior corrosion resistance, and significantly longer service life.
At RPC, we’ve been leading this shift for over 20 years. These GRP shaft structures can be installed in days rather than weeks, reducing traffic disruption, labour costs, and on-site safety risks. Their corrosion-resistant laminate construction performs far better than concrete in aggressive sewer environments, while remaining lightweight and structurally robust for deep installations. Factory-controlled manufacturing ensures consistent quality, with integrated vortex structures, drop pipes, and structural liners delivered ready to install.
Designed for a 100+ year asset life, our Australian-engineered GRP solutions offer a durable, low-maintenance, and future-proof alternative to traditional construction.
Designed exclusively by RPC engineers, the RPC PermaManhole is a semi-structural GRP manhole liner with an integrated channel liner with an O-ring seal. Eliminating the need for in-situ placement of reinforced steel in mass concrete encasement, the RPC solution minimises man-entry requirements and work in confined spaces.
Once the channel liner is installed and the joint tested, the GRP manhole liner can be installed, supported by a steel support frame at ground level.
Working with you to properly define the scope of your requirements, RPC can design, manufacture and deliver the PermaManhole structure that will present the easiest installation method. Our factory installs manhole liner ancillaries such as vortex structures, drop pipes, support clamps and ladders, so the complete assembly only needs to be dropped into place once delivered to site.
One-piece delivery minimises public interruption and significantly reduces installation time. Work health and safety risk is also minimised by avoiding the need for site personnel to access the manhole cavity during installation.
Our liners provide structural formwork that is capable of being placed into the excavations as a single or multi-piece segment and continuously concrete-encased in a single pour process.
Specifications
Customer story
Most people never think about maintenance shafts, yet they're some of the most critical structures in our sewer networks. They enable safe access for maintenance, ventilation, and inspection and they must withstand decades of chemical exposure, groundwater pressure, and structural loads.
Most people never think about maintenance shafts, yet they’re some of the most critical structures in our sewer networks.
Tell us about your project and we’ll connect you with the right sector team.