Use our Flexible Pavement Structural Number Calculator to efficiently determine the required structural capacity for your pavement design. This tool assists engineers in applying AASHTO pavement design principles, considering layer coefficients and drainage, crucial for durable infrastructure projects.
Formula:
Formula for Structural Number (SN)
The Structural Number (SN) for flexible pavements is calculated using the following general formula, based on AASHTO principles:
SN = a1D1m1 + a2D2m2 + a3D3m3 + ... + anDnmn
- SN: Structural Number (unitless) - Represents the structural capacity of the pavement.
- ai: Layer coefficient for layer 'i' (unitless) - A measure of the relative ability of the material in layer 'i' to function as a structural component.
- Di: Thickness of layer 'i' (inches) - The physical depth of the pavement layer.
- mi: Drainage coefficient for layer 'i' (unitless) - Adjusts the structural capacity based on the quality of drainage and saturation level of the layer.
For this calculator, we consider three primary layers: Surface Course, Base Course, and Subbase Course.