The design of rigid pavement in Australia has traditionally followed, albeit with modifications, the Portland Cement Association method. This method is based on limiting the concrete flexural stress under load and pavement distress caused by the erosion of the sub-base and/or subgrade at the joints. The design method is based on an iterative system which makes the design process tedious if the initial base thickness chosen in the calculations is not close to the actual required thickness. In 1988 the State Road Authority pavement engineers adopted, with the assistance of ARRB Transport Research, the PCA design methodology for the AUSTROADS Pavement Design Guide. In the Guide, modifications to the design tables in the PCA method were made to allow for Australian commercial vehicle axle configurations. This paper suggests a spreadsheet approach to the calculation of the total fatigue and erosion distress for each commercial vehicle axle group. The detailed algorithms in this paper also provide the pavement designer with greater efficiencies in the design procedure. The NSW RTA's Pavement Branch has also developed a sophisticated spreadsheet utilising the macro functions in Lotus 123. This program incorporates the stress ratio and erosion factor tables in the AUSTROADS Guide. The program's input and output parameters are detailed in this paper. (A)
Abstract