Transurban identified fourteen (14) pavement failures that occurred on the Logan Motorway eastbound carriageway where corrective maintenance was required to ensure safe lane availability. Maintenance records from the 5th October 2016 detail repairs consisting of asphalt (AC) patch repairs ranging from a depth of 100mm to 200mm. These repairs were constructed to replace the defective pavement layer with new pavement material and act as a holding treatment until more substantial pavement rehabilitation occurs.
Considering the unexpected frequency of pavement failures particularly post rain events, The Principal engaged the services of an external engineering consultant to undertake a pavement and drainage review and root cause analysis into the pavement failures. Following the preliminary assessment of pavement failures and drainage issues Transurban engaged GHD to prepare Detailed Design Tender documents for necessary drainage improvements and pavement rehabilitation for a 2.4 km section of the Logan Motorway Eastbound between the Centenary Highway and Stapylton Road. The preliminary assessment has identified various drainage issue for the entire section and pavement failures along a 500m section requiring improvements and rehabilitation respectively.
Transurban required Bellwether to assist with GHD to effectively develop a cost-effective value for money design solution.
Bellwether provided Cost Estimates (in conformance with TMR’s Project Cost Estimating Manual) and Basis of Estimate Reports for two options and a category 5 cost estimate for the preferred option.
These estimates provided certainty which allowed the project to progress.