Design certification by RH Consulting Pty Ltd
Mascot Engineering Glass Reinforced Concrete (GRC) Pits, Risers, Channel and Covers
Mascot Engineering Group has been manufacturing their Glass Reinforced Concrete (GRC) range since 1984. Up until 2005, design and certification was provided by Rickard and Partners Pty Ltd, under the supervision of Principal Charles Rickard. Since 2005, that support has continued from Mr Rickard practising as RH Consulting Engineers (see website for reference). We make the following comments regarding the product range.
Method of Manufacture
Mascot Engineering use a vibration, wet cast premix GRC technique for all their product range. This technique was originally developed by Pilkington Bros in the 1950s.
Mascot Engineering GRC pits and risers range are applicable to be installed in trafficable areas (roads and driveways), garden beds / parks, service access roads, sporting venues, rail corridors, shopping centres, water treatment plants, power stations and any other application where a pit chamber is required. All applications are supported by installation instructions and methodology.
Characteristic MOR GRC Strength at 28days
- Vertical bending; 7.5MPa
- Horizontal bending; 16.5MPa
The very high cement content in Mascot Engineering’s GRC ensures that it is equivalent to 80MPa concrete and therefore has very high resistance to corrosion. The fire resistance / surface burning rating, chemical resistance and water absorption details are attached. Refer to Characteristics of GRC.
Lateral Impact and Live Load Surcharges
In reference to the live load surcharges on pit walls, we consider that Mascot GRC pit chambers are suitable to withstand the lateral earth pressures in excess of 20KPa.
Mascot GRC pits and risers have been designed and manufactured to endure the vertical and horizontal forces due to the live loading delivered by heavy articular vehicles and rail carriages.
From tests conducted relating to GRC curing and strength over a period of time, the MPa rating of Mascot GRC reached 60 Mpa over 28 days (Refer to Mascot GRC GR Concrete Facts sheet).
Mascot GRC Covers
Should the Engineers specification require non conductive covers, Mascot manufactures a GRC lightweight pedestrian duty cover for their pit chamber range.
Pipe / Conduit Penetrations
Pipe / Conduit penetrations are made possible in an endless variety of geometrics so as to not compromise the installation. This includes the scenario where a conduit penetrates a pit wall through the strength rib.
In strict accordance with specification, reinstatement of structural integrity is achieved in that case by ‘bonding’ the pipe to the pit wall with Mascot’s Epoxy Resin Compound. This allows the crush strength of the pipe to be called upon.
Specification and Installation
Refer to the standard specification sheet for Mascot GRC pit chambers and installation instructions to satisfy Class A to Class D load ratings in various surface applications and in accordance with AS 3996:2019.
In addition to their standard installation methods, also available are;
- RTA Class D load rating special installation instruction for Mascot pit chambers to be installed within, or on an RTA roadway and motorway.
- Installation instructions for a Class G load rating ideally for Airports and Container handling yards.
- Installation instructions for Pit Chambers to be installed in excess of 1800mm in depth.
Where the Design Engineers Specification for installation varies to the Mascot Engineering Installation instructions, installers should seek further advice. To ensure maximum value from the product design calculations and test load results, it is strongly advised that the contractor familiarise themselves with the recommended method of installation to cater for the correct loads to be superimposed. This issue of care during installation will most certainly be the determining factor as to the quality, longevity and service life of the product.
Charles Rickard FIEAust, FIStructE, MICE, CEng, MIPENZ, NPR-3
RH Consulting Pty Ltd