Skip to content
Pavement
Interactive
Reference Desk
Tools
Glossary
For educators
Sign in
Menu
Home
Tools
Structural number from layers
Structural number from layers
1993 AASHTO Guide
Explained in
Structural Number
Calculator
Structural number from layers
1993 AASHTO Guide
Units
US customary
SI (metric)
Surface
Surface thickness, D
1
, in.
Layer coefficient, a
1
Base
Base thickness, D
2
, in.
Layer coefficient, a
2
Drainage coefficient, m
2
Subbase
Subbase thickness, D
3
, in.
Layer coefficient, a
3
Drainage coefficient, m
3
Calculate
Example values. Set a thickness to 0 for a layer you don’t have.
All tools