Table 1 - Partial List of Layer Moduli Backcalculation Programs [Rada et al]
| Program Name | Developed By |
Forward Calculation Method | Forward
Calculation Subroutine |
Back- calculation Method |
Non-Linear Analysis | Rigid Layer Analysis | Layer Interface Analysis | Maximum Number of Layers | Seed Moduli | Range of Acceptable Modulus | Ability to Fix Modulus | Convergence Routine | Error Convergence Function | ||
| BISDEF | USACE-WES | Multi-Layer Elastic Theory |
BISAR(Proprietary) | Iterative | No | Yes | Variable | Cannot Exceed No. of
Deflec., Works Best For 3 Unknowns |
Required | Required | Yes | Sum of Squares of Absolute Error | Yes | ||
| BOUSDEF | ZHOU, et.al. OREGON STATE UNIV. |
Odemark- Boussinesq |
Odemark- Boussinesq |
Iterative | Yes | Yes | Fixed(Rough) | 5, Works Best for 3 Unknowns | Required | Required | Yes | Sum of Percent Errors | Yes | ||
| CHEVDEF | USACE-WES | Multi-Layer Elastic Theory |
CHEVRON | Iterative | No | Yes | Fixed(Rough) | Cannot Exceed No. of
Deflec., Works Best For 3 Unknowns |
Required | Required | Yes | Sum of Squares of Absolute Error | Yes | ||
| ELMOD/ ELCON |
P. ULLIDTZ DYNATEST | Odemark- Boussinesq |
Odemark- Boussinesq |
Iterative | Yes(Subgrade Only) | Yes(variable) | Fixed(Rough) | Up to 4, Exclusive of Rigid Layer | None | No | Yes | Relative Error on 5 Sensors | No | ||
| ELSDEF | TEXAS A&M UNIV.,USACE-WES | Multi-Layer Elastic Theory |
ELSYM5 | Iterative | No | Yes | Fixed(Rough) | Cannot Exceed No. of Deflec., Works Best For 3 Unknowns | Required | Required | Yes | Sum of Squares of Absolute Error | Yes | ||
| EMOD | PCS/LAW | Multi-Layer Elastic Theory |
CHEVRON | Iterative | Yes(Subgrade Only) | No | Fixed(Rough) | 3 | Required | Required | Yes | Sum of Relative Squared Error | No | ||
| EVERCALC | J. MAHONEY, et.al. | Multi-Layer Elastic Theory |
CHEVRON | Iterative | Yes | Yes | Fixed(Rough) | 3 Exclusive of Rigid Layer | Required | Required | Yes | Sum of Absolute Error | No | ||
| FPEDDI | W. UDDIN | Multi-Layer Elastic Theory |
BASINPT | Iterative | Yes | Yes(Variable) | Fixed(Rough) | Unknown | Program Generated | Unknown | Unknown | Unknown | No | ||
| ISSEM4 | R. STUBSTAD | Multi-Layer Elastic Theory |
ELSYM5 | Iterative | Yes(Finite Cylinder Concept) | No | Fixed(Rough) | 4 | Required | Required | Yes | Relative Deflec. Error |
No | ||
| MODCOMP3 | L. IRWIN, SZEBENYI | Multi-Layer Elastic Theory |
CHEVRON | Iterative | Yes | Yes | Fixed(Rough) | 2 to 15 layers, Max 5 Unknown Layers | Required | Required | Yes | Relative Deflec. Error at Sensors | No | ||
| MODULUS | TEXAS TRANS. INSTITUTE | Multi-Layer Elastic Theory |
WESLEA | Data Base | No | Yes(Variable) | Fixed? | Up to 4 Unknown plus Stiff Layer | Required | Required | Yes | Sum of Relative Squared Error | Yes | ||
| PADAL | S.F. BROWN, et. al. |
Multi-Layer Elastic Theory |
UNKNOWN | Iterative | Yes(Subgrade Only) | Unknown | Fixed? | Unknown | Required | Unknown | Unknown | Sum of Relative Squared Error | Unknown | ||
| WESDEF | USACE-WES | Multi-Layer Elastic Theory |
WESLEA | Iterative | No | Yes | Variable | Up to 5 Layers | Required | Required | Yes | Sum of Squares of Absolute Error | Yes | ||
| MICHBAK | MICHIGAN STATE | Multi-Layer Elastic Theory |
CHEVRON | Iterative | No | Yes | Fixed | Up to 4 Unknown plus Stiff Layer | Required | Optional | Yes | Sum of Relative Squared Error | Yes |