The CivilWeb AASHTO 1993 Pavement Design Spreadsheet The AASHTO flexible pavement design spreadsheet then compares the required Structural Number with the Structural Number of the proposed pavement design and returns whether the pavement design is valid or not in accordance with the AASHTO 1993 method. The designer can instantly see the contribution of each layer making it easy to optimise the design by adjusting the thicknesses of each layer. The AASHTO flexible pavement design spreadsheet automatically calculates the Structural Number of each layer and adds them together to get the total Structural Number of the pavement. The designer must input the thickness, stiffness and material coefficients for each layer in the proposed pavement design. Typically a flexible road system will include 3 or 4 different layers of material. Next the designer must input a proposed pavement design which the spreadsheet will evaluate for suitability. The suite also includes additional spreadsheets which can be used to estimate traffic loadings from traffic distribution and survey data. The CivilWeb AASHTO 1993 Pavement Design Spreadsheet Suite includes a number of additional spreadsheets which can be used to estimate the resilient modulus of sub-base, granular and underlying soils.

The AASHTO flexible pavement design excel spreadsheet takes these inputs and instantly calculates the total required Structural Number to suit these loading conditions. The designer first must input the loading conditions which include the number of standard axles the road will need to take, the support offered to the road by the underlying ground, the amount of damage expected to be inflicted on the road during its design life and the reliability of the design. AASHTO 1993 Pavement Design - Design InputsĪs described above, first the spreadsheet calculates the required Structural Number to suit the loading conditions. The optimisation of the design will also save time and money on the construction phase of the project. Using the CivilWeb AASHTO 1993 Pavement Design Spreadsheet will save the designer hours on every single flexible road design. This allows the designer to optimise the design at a glance, showing exactly how many load repetitions relate to a particular Structural Number. The CivilWeb AASHTO 1993 Pavement Design Spreadsheet also includes a unique design graph showing the total Structural Number required to accommodate any loading conditions.

The AASHTO flexible pavement design excel spreadsheet completes the Structural Number calculations instantly, allowing the designer to complete dozens of different design iterations in minutes. The whole process must be repeated several times in order to optimise the thicknesses of each layer and this may need to be repeated to investigate different pavement types. Each layer is given a Structural Number, and the total of the Structural Numbers of each layer in the system must exceed the required Structural Number derived from the loading conditions.Ĭompleting the Structural Number calculations can be tedious, particularly where the loading conditions are uncertain or where the pavement design must be optimised. The AASHTO 1993 method evaluates the structural strength contribution of each layer in the pavement system based on its thickness and stiffness. This takes the form of an overall Structural Number. This empirical equation is used to determine the total structural strength required to resist the proposed traffic loads. The AASHTO 1993 method is based on an empirical equation developed from road performance information gathered from the AASHTO Road Test. Flexible pavement design according to the AASHTO 1993 guide can be very time consuming.

Flexible pavement design software