From the magazine

Making it big with GRP

The Woolloongabba Sewer was one of Australia’s largest and most challenging projects of its kind.

Constructed by John Holland for Queensland Urban Utilities, the 4.5 km long DN1400 sewer was originally designed in a rigid pipe material.

After many discussions between contractor, designer and asset owner, it was decided that the lowest risk pipe material for this high-risk project was HOBAS centrifugally cast (CC) glass reinforced (GRP) jacking pipe.

The pipe grades were 1 in 800, so dimensional accuracy was imperative.

This tricky project on the fringe of the Brisbane CBD presented some challenges with traffic management.

Even though pipe was installed up to 15 m below the surface of the city streets, the installation was still a resounding success. Additionally, with curved drives over 440 m in length, new benchmarks were set.

Intermediate jacking stations were allowed for in the longer drives, but in most cases not required.

In 2014, Edge Underground worked with Fulton Hogan to complete the third stage of the Warragul Sewer for Gippsland Water.

The design called for GRP pipe and a lot of this was to be tunnelled due to very poor ground conditions including gravel, boulders, wet clay and wet sand with a very high degree of saturation.

The total of 1.4 km of jacking pipe ranged from OD427 up to OD718.

Given the wet sandy ground, the lowest risk option was favoured by all, and there was no hesitation from anyone involved to choose HOBAS pipe for the project.

Edge Underground installed pipe without issue in bores up to 7 m deep and including drives of 148 m.

The HOBAS-Global Pipe partnership

HOBAS is the international leader in the supply of GRP high performance pipe systems for jacking applications.

Over the past decade, Global Pipe has established a strong reputation as a supplier of premium quality pipe and installation solutions within both the Australian and New Zealand markets.

Through the combined resources of Global Pipe and HOBAS, an unparalleled range of pipe systems and associated services is provided. Such services include:

  • Pipe systems and solutions for all project types, be they large or small;
  • Resources and support in project design including design calculators, 3D CAD pipe and fitting designs along with static load calculations and hydraulic calculations;
  • “÷On the ground’ technical advice, site supervision and support;
  • The guarantee of an “÷on time on spec’ outcome for any project undertaken.

A HOBAS history

Established for more than 50 years, HOBAS CC GRP pipe products are based on patented production technologies resulting in optimal performance characteristics not found in other GRP pipe products.

Class-leading internal hydraulics, light-weight, smooth exterior finish for lower jacking loads, high corrosion resistance along with a successful track record with curved jacks and inter-jack stations combine with the practical benefits of:

  • Smaller external diameters for reduced tunnel bore size and associated savings in bore excavation costs;
  • The lighter weight of HOBAS pipe products, enabling longer drives and an overall reduction in project footprint;
  • Extensive long-term testing and durability studies, which reveal that HOBAS jacking pipe has a design life of more than 100 years
  • .

HOBAS’s proven product strengths, along with a comprehensive range of pipe sizes (from 200-3,600 mm) provides a class-leading solution for any “÷no-dig’ project.

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