High strength geosynthetics for bridge foundations along Queensland’s Bruce Highway

ACETex® high strength geosynthetic is being used to reinforce the foundations of new flood-immune bridges at Saltwater Creek and Deadmans Gully along the Bruce Highway in Aldershot, Queensland.

Project snapshot

The Department of Transport and Main Roads (TMR) has contracted Georgiou Group to construct two new high-level bridges on a new alignment west of the existing highway, as part of a safety improvement and flood immunity project.

Located at Aldershot on the Bruce Highway between Maryborough and Torbanlea, the project has received funding from the State and Federal governments, and will improve road safety and flood tolerance by upgrading the two main waterway crossings and other nearby floodways to provide a one in 100 year flood event immunity.

The project includes two new bridges traversing Saltwater Creek and Deadmans Gully on this section of road, as part of the Bruce Highway Upgrade program.

The upgrading will improve safety along this section of the Bruce Highway and provide less traffic disruption due to flooding in the future.

The challenges

The new concrete bridges will be founded on piles, and the approaches will be constructed with compacted fill over a low strength subgrade.

The design, conducted by Jacobs, required this area to be consolidated with preload and reinforced with high strength geosynthetic complying with TMR's MRTS100 specification. The design indicated that reinforcement should be placed horizontally under the embankment preload, controlling stability during the preload phase.

High strength geosynthetic reinforcement can be manufactured as either a geogrid or a woven geotextile and is commonly used where long-term static loads need to be reinforced or retained. Reinforcement ranges in strength from around 100kN/m to more than 1000kN/m ultimate tensile strength.

Note: When designing with high strength geosynthetic reinforcement materials, the designer must nominate a required design or working load at a required level of strain at some time in the future to allow the appropriate product grade to be selected. An annexure is provided in TMR's MRTS100 with these details. 

Our solution

Global Synthetics was contacted by Georgiou Group to assist in selecting an appropriate geosynthetic reinforcement.

The technical engineering team at Global Synthetics selected two products to meet the project requirements: ACETex GT800/50 for the Deadmans Gully site, and ACETex GT400/50 for the Saltwater Creek site. These solutions satisfied the necessary reinforcement stress, strain, and design life requirements.

ACETex GT800/50 offers an ultimate tensile strength of more than 800kN/m, and ACETex GT400/50 offers 400kN/m, both at less than 10 per cent strain over long project design periods.

Global Synthetics successfully supplied this required material in a timely manner to meet the Georgiou construction program.

Our engineers are always here to provide advice, technical support and selections for our customers. For further information or to enquire about geosynthetic solutions for your next project, contact Jason Crase at jason@globalsynthetics.com.au.