Ipswich Motorway is the principal corridor between Ipswich and Brisbane. The Rocklea to Darra section of the motorway connects directly to the Brisbane Urban Corridor at Rocklea and the Centenary Motorway/Ipswich Motorway interchange at Darra. The Department of Transport and Main Roads (TMR) has decided on the staged delivery of a series of road projects to complete the overall Ipswich Motorway upgrade, with the first package between Granard and Oxley Road, delivering the following outcomes:

• Improved traffic flow and reduced congestion creating more reliable travel times
• Upgraded road safety on the motorway with improved sight distances and safer access to and from the motorway
• Enhanced local connectivity for all road users, pedestrians and cyclists with new service road connectors reducing the need for local trips on the motorway
• Improved flood immunity through construction of higher bridges over the Oxley and Little Doris Creeks

HDR completed the tender design for this project as part of a Design Joint Venture with GHD working for the BMD John Holland Joint Venture.

Significant challenges included the Oxley Creek floodplain presenting hydraulic challenges including raising the motorway alignment several metres along with the poor ground conditioning evident, resulting in preloading and rigid inclusions on the bridge approaches. In addition the traffic management had to be cognizant of the needs of local business owners and access to local and service roads.

Some of the innovations incorporated into the tender design included:

• Combining the Oxley Creek and overflow bridges into a single structure to minimise the risk associated with poor ground conditions
• Designing the Service Roads including structures to accommodate motorway traffic diversions to assist traffic management
• Providing a cost effective alternative at-grade interchange at Granard Road in lieu of the ultimate grade separated interchange