Lake Margaret Hilltop Pipeline Replacement 2008/09
The Lake Margaret Hydro-Electric Power Scheme was built between 1912 to 1914, and included a woodstave pipeline to connect the dam to the pressure penstock feeding the power station. The original woodstave pipeline was replaced in 1937 by another constructed from locally sourced King Billy Pine. That pipeline remained in service until 2006, when safety concerns caused it to be taken out of service. Community pressure lead to the scheme being heritage listed in 2006. Hydro Tasmania committed to keeping the power station in service in its original form, including construction of a replacement woodstave pipeline.
The Project
Hazell Bros Group, teamed with JMG Engineers and Planners, won the D&C contract for the new woodstave pipeline, with materials for the woodstave pipeline being supplied by International Tank & Pipe Co. of Portland, Oregon, USA.
Key Issues
The design reuses the 1937 concrete footings wherever possible. The steel substructure that supports the pipe doubles as a track for an innovative trolley system that is used to handle materials and provide a safe work platform for the construction crew in the remote and difficult terrain. The trolley system meant that any error in design, fabrication of construction would lead to extensive delays, as the steelwork was all fabricated off site and galvanised before being transported to site. There were over 600 different trestles and rail spans which were all separately detailed. JMG also designed lightweight trusses to span several unstable areas to support the pipe and trolley loads, these were designed to allow placement on site by helicopter as there is no vehicle access to the site.
The Project received a prestigious Engineering Excellence Award at the 2009 Tasmanian Division Awards for Engineering Australia.
For more information about JMG’s structural engineering services, contact Grant Atherton on (03) 62312555 or email contact.hbt@jmg.net.au.
For the project sheet on this project, click here.