AASHTO 1993 Pavement Design Spreadsheet

AASHTO 1993 Pavement Design

Flexible pavement design according to the AASHTO 1993 guide can be very time consuming. The AASHTO 1993 method is based on an empirical equation developed from road performance information gathered from the AASHTO Road Test. This empirical equation is used to determine the total structural strength required to resist the proposed traffic loads. This takes the form of an overall Structural Number.

The AASHTO 1993 method evaluates the structural strength contribution of each layer in the pavement system based on its thickness and stiffness. 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.

Completing the Structural Number calculations can be tedious, particularly where the loading conditions are uncertain or where the pavement design must be optimised. 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. 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 CivilWeb AASHTO 1993 Pavement Design Spreadsheet also includes a unique design graph showing the total Structural Number required to accommodate any loading conditions. This allows the designer to optimise the design at a glance, showing exactly how many load repetitions  relate to a particular Structural Number.

Using the CivilWeb AASHTO 1993 Pavement Design Spreadsheet will save the designer hours on every single flexible road design. The optimisation of the design will also save time and money on the construction phase of the project.

AASHTO 1993 Pavement Design - Design Inputs

As described above, first the spreadsheet calculates the required Structural Number to suit the 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. The AASHTO flexible pavement design excel spreadsheet takes these inputs and instantly calculates the total required Structural Number to suit these loading conditions.

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 suite also includes additional spreadsheets which can be used to estimate traffic loadings from traffic distribution and survey data.

Next the designer must input a proposed pavement design which the spreadsheet will evaluate for suitability. Typically a flexible road system will include 3 or 4 different layers of material. The designer must input the thickness, stiffness and material coefficients for each layer in the proposed pavement design.  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 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 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 CivilWeb AASHTO 1993 Pavement Design Spreadsheet

The CivilWeb AASHTO 1993 Pavement Design Spreadsheet Suite includes a number of additional spreadsheets allowing the designer to complete any of the calculations required for a fully compliant AASHTO1993 pavement design.  The suite includes;

1. AASHTO 1993 Structural Pavement Design Spreadsheet - The main structural design spreadsheet as described above.
2. AASHTO 1993 Traffic Loading Distribution Spreadsheet - This spreadsheet calculates the estimated design traffic loading from traffic distribution data.
3. AASHTO 1993 Traffic Loading Survey Spreadsheet - This spreadsheet calculates the number of standard axles expected over the design life of the road from traffic survey data.
4. AASHTO Resilient Modulus Correlations Spreadsheet - This spreadsheet uses published correlations with CBR, LBR and R value to estimate the resilient modulus of soils.
5. AASHTO Resilient Modulus from Soil Data Spreadsheet - This spreadsheet estimates the resilient modulus of soils from soils data.
6. AASHTO Sub-Base Resilient Modulus Spreadsheet - This spreadsheet estimates the resilient modulus of sub-base materials from stress data.
7. AASHTO Effective Resilient Modulus Spreadsheet - This spreadsheet calculates the effective resilient modulus of materials which are affected by the weather at different times of the year, for example soils which freeze and are very stiff over the winter and then thaw and are soft in the spring.
8. AASHTO Layer Coefficient from Resilient Modulus Spreadsheet - This spreadsheet calculates the structural coefficient of sub-base and granular materials from the resilient modulus.
9. AASHTO PSI Spreadsheet - This spreadsheet can be used to calculate a roads existing PSI based on a site inspection of damage. This is essential for the evaluation of the structural capacity of existing roads.

The CivilWeb AASHTO 1993 Pavement Design Spreadsheet Suite includes unique analysis tools allowing the designer to complete and optimise a fully compliant flexible pavement design in accordance with the AASHTO 1993 method in minutes. Buy now for only £10.