AASHTO 1993 Flexible Pavement Structural Number Calculator

Quick Answer

Calculate AASHTO 1993 Flexible Pavement Structural Number Calculator

Result Interpretation

AASHTO 1993 Flexible Pavement Structural Number Calculator computes Structural Number in dimensionless using the defined engineering formula and the input values provided.

Worked Example

Verified calculation

Given:

Log base 10 of subgrade CBR = 1
Log base 10 of cumulative 18-kip equivalent single axle loads (ESALs) = 6

Expected Result:

Structural Number = 148.13684248844

Engineering Interpretation:

Under the given input conditions, the calculated result is: Structural Number = 148.13684248844 dimensionless.

The actual numerical result is computed by the Runtime engine using the persisted tool definition. The values shown here come from automatically validated test cases.

Formula / Method

structural number = 0.42 * pow(10, (ESALs - 0.67 * log base 10 of subgrade cbr + 0.58) / 2.32)

Formula family: formula_roads_subgrade_cbr_traffic_volume_design_life_structural_number_calculator

Variables

Symbol	Label	Role	Description
log10_axle_loads	Log base 10 of cumulative 18-kip equivalent single axle loads (ESALs)	INPUT	Log base 10 of cumulative 18-kip equivalent single axle loads (ESALs)
log10_cbr	Log base 10 of subgrade CBR	INPUT	Log base 10 of subgrade CBR
structural_number	Structural Number	OUTPUT	Structural Number

Calculation Steps

Enter the log base 10 of cumulative 18-kip equivalent single axle loads (esals) in dimensionless.
Enter the log base 10 of subgrade cbr in dimensionless.
Step 1: Compute structural number.
Read the structural number (dimensionless) from the results.

Engineering Summary

Calculate AASHTO 1993 Flexible Pavement Structural Number Calculator

Frequently Asked Questions

What does this calculator calculate?

The AASHTO 1993 Flexible Pavement Structural Number Calculator estimates Structural Number based on the input parameters you provide

Why is log base 10 of cumulative 18-kip equivalent single axle loads (esals) important in this calculation?

log base 10 of cumulative 18-kip equivalent single axle loads (esals) is directly proportional to structural number. When you enter log base 10 of cumulative 18-kip equivalent single axle loads (esals) in dimensionless, the calculator uses it in the engineering formula to compute the output

How should I interpret the result structural number?

The calculator outputs structural number in dimensionless. The result is computed directly from the input values using the defined engineering formula

What units should I use for the inputs?

Enter each value in the units shown next to the input field: Log base 10 of cumulative 18-kip equivalent single axle loads (ESALs) (dimensionless), Log base 10 of subgrade CBR (dimensionless). Make sure all inputs use the specified units for consistent results

What assumptions does this calculator use?

This calculator uses automatically validated engineering formulas. Results are approximate and should be validated against site-specific conditions, applicable codes, and professional engineering judgment