# Example 8-1 · Strip footing on a c–φ soil

Example 8-1 of Samtani & Nowatzki (2006), Soils and Foundations Reference Manual, Volume II, solved in Rischio and compared with the source's answers.

SourceManual

Samtani, N. C., & Nowatzki, E. A. (2006). Soils and Foundations Reference Manual, Volume II (FHWA-NHI-06-089). Federal Highway Administration. Example 8-1, p. 8-21.

ID `fhwa-nhi-06-089-8-1`

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The model as the editor draws it, with what governs its result.

## Source vs Rischio

|  | Source | Rischio | Difference |
| --- | --- | --- | --- |
| Bearing capacity factor Nc | 14.8 | 14.8 | +0.2 % |
| Bearing capacity factor Nq | 6.4 | 6.40 | 0.0 % |
| Bearing capacity factor Nγ | 5.4 | 5.39 | −0.3 % |
| Cohesion term, c Nc | 354.31 kPa | 355.14 kPa | +0.2 % |
| Surcharge term, γ Df Nq | 191.52 kPa | 191.50 kPa | 0.0 % |
| Weight term, ½ γ B Nγ | 96.96 kPa | 96.71 kPa | −0.3 % |

AASHTO's 10th edition puts a depth factor dq on the surcharge term, which the 2006 example's equation doesn't carry: the surcharge term is shown without it.

## How it's calculated

-   [Method and assumptions → What the engine does, and what it assumes.](https://rischio.io/docs/shallow-foundation/theory/)
-   [Equations → Every step of the calculation, in order.](https://rischio.io/docs/shallow-foundation/equations/)
-   [Inputs → Every field of the model, with its units.](https://rischio.io/docs/shallow-foundation/inputs/)

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Source: https://rischio.io/docs/examples/fhwa-nhi-06-089-8-1/