Project Profile Duplication, WA

CLIENT Main Roads WA YEAR 2014 SCOPE OF WORK • Geotechnical investigation • Interpretive analyses and reporting • Bridge foundation advice • Existing pavement assessment • Pavement design

Investigation for the new bridge in progress.

Traffic volumes on Reid Highway were significantly greater than the capacity of the two lane road between Duffy Road and . Douglas Partners provided geotechnical and pavement advice for a second carriageway through this stretch of highway, incorporating a new bridge crossing both and the Butler railway line.

Reid Highway forms the northern loop bridge included boreholes and test pits for the bridge footings, earthworks, of ’s Metropolitan Strategic Outer for the abutments beside the Mitchell assessment of the adequacy of the Ring Road. The objective of the project Freeway. A foundation of the bridge existing pavements and design of the was to increase the traffic capacity Reid had previously been constructed within new pavements. Highway, which regularly experienced the rail reserve. Ground The field works required considerable traffic congestion, by adding a second penetrating radar (GPR) was used to logistical planning, including traffic 2 km long carriageway between confirm the location of this footing. management plans for works beside the Erindale Road and Duffy Road. Douglas The GPR was extended to include Mitchell Freeway. Rail safety plans were Partners was engaged by Main Roads the abutment locations to seek to mandatory to work within the rail reserve WA to undertake the geotechnical identify potential karst features in the and obtaining timely approval for these investigation works for the project, limestone. Buried utilities were identified was key to delivering the project within which is located in an area underlain by and potholed using vacuum drilling the tight timeframe. The project was Tamala limestone. for accurate survey to inform detailed delivered on time, the significant driver design. Investigations for the client, and within budget. for the The remaining areas of new carriageway new required test pits and, where site “Close liaison and cooperation with constraints required, hand augers our project partners and Main Roads to identify and sample the underling soils. Test pits were excavated within WA was essential to deliver this the existing carriageway to assess complex investigation on time, and the existing pavement and underlying to provide all the necessary advice.” subgrade. Additionally, falling weight deflectometer (FWD) testing and a Paul Hutchinson surface condition survey using an Project Manager Automatic Road Analyser (ARAN) were conducted. The findings of the field works were used to provide recommendations

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