Pavement Design Excel Spreadsheet !link! — Aashto Flexible
variable appears on both sides of the equation, you cannot solve it directly. Engineers use iterative methods or Excel tools like to solve for SNcap S cap N Key Input Parameters for the Spreadsheet
To build a functional AASHTO 1993 Flexible Pavement Design spreadsheet, you need to implement the core empirical equation that relates traffic ($W_18$), reliability ($Z_R$), overall standard deviation ($S_o$), structural number ($SN$), and the change in serviceability ($\Delta PSI$).
A built-in VBA button that runs the iterative calculation automatically when inputs change. aashto flexible pavement design excel spreadsheet
A typical AASHTO design spreadsheet is structured into three distinct sections:
Sub SolveForSN() Range("A22").GoalSeek Goal:=0, ChangingCell:=Range("A20") MsgBox "Required SN = " & Round(Range("A20").Value, 3) End Sub variable appears on both sides of the equation,
The 1993 AASHTO method assumes:
Constraints for asphalt, base, and subbase layers. 3. Structuring Your AASHTO Flexible Pavement Spreadsheet A typical AASHTO design spreadsheet is structured into
| Feature | Must-Have? | | :--- | :--- | | AASHTO 1993 equation embedded correctly | ✔️ Absolute | | Units toggle (inches/mm, psi/MPa) | ✔️ Recommended | | ESAL input in millions or single values | ✔️ | | Drainage coefficient table | ✔️ | | Layer thickness rounding to construction standards (0.5 inch) | ✔️ | | Comparison chart (Required SN vs. Provided SN) | ✔️ | | No VBA required? (Goal Seek manual button okay) | Acceptable | | Password protection (to prevent accidental formula break) | Bonus |
Provided SN = 4.03 (>3.95). The spreadsheet also generated a cost comparison: using 6-inch asphalt with 8-inch base was $18,000 more per mile. The chosen design saved money.
Pavement damage is not calculated by the total number of vehicles, but by the cumulative damaging effect of axle loads converted into .