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Lythos Bearing

Bearing capacity of shallow foundations, driven from your browser. A rectangular, square, strip or circular footing on a layered soil profile, under a vertical load, horizontal loads and moments, is checked by every method an engineer is likely to be asked for, side by side:

1. The general bearing capacity equation with the factor sets of Terzaghi (1943), Meyerhof (1963), Brinch Hansen (1970), Vesić (1973) and EN 1997-1 Annex D, and Skempton's (1951) undrained Nc — each with its own shape, depth, load inclination, base tilt, ground slope and (Vesić) compressibility factors; drained, undrained, or whichever governs; general or local shear.
2. Eccentric and inclined loads — Meyerhof's effective area, the contact pressure under the base and the middle-third rule.
3. Layered ground — the strength averaged over the Prandtl failure zone, or the two-layer punching check of Meyerhof & Hanna and the load-spread check for a strong layer over a weak one.
4. In-situ tests — Meyerhof's SPT and CPT rules and Ménard's pressuremeter rule.
5. Rock — Hoek–Brown turned into an equivalent c′, φ′, and the CFEM discontinuity-spacing method.
6. Earthquake — pseudo-static inertia of the structure, and Paolucci & Pecker's reduction for the inertia of the soil.
7. Checks — bearing, sliding and eccentricity against a factor of safety, or EN 1997-1 Design Approaches 1, 2 and 3, and the width the foundation needs.

On top of it, a parametric or reliability study sweeps any input — a range, or a distribution — and reports sensitivities and the probability of failure in bearing, sliding and eccentricity, with a confidence interval and the reliability index β.

The whole program — every label, result text, figure and report — is bilingual in English and Turkish, switchable while it runs.

The interface is a small HTTP server on your own machine, driven from a browser. That keeps the program usable over a remote session or inside a container, where a desktop toolkit would need a display it does not have, and it costs no dependency beyond the standard library.

This is the sibling of LythosFEA, Lythos Settle, Lythos Kinematic, Lythos SPWA and LythosLE, and follows the same architecture, theme and fonts.

Screenshots

Results summary	Comparison of the methods

Section and failure mechanism, dark theme, Turkish	Capacity against width

V–H failure envelope	Reliability study

Install & run

From a clone, with nothing installed but the scientific stack:

pip install numpy matplotlib reportlab
python main.py

or install it and use the command:

pip install .
lythos-bearing                     # opens the interface in your browser

main.py puts its own directory first on the import path, so the clone's code is what runs even when lythosbearing is also installed.

Python 3.10+ is required. Word reports need python-docx and the spreadsheet export of a study needs openpyxl; both are extras (pip install ".[docx,xlsx]").

Command line

lythos-bearing                                  # web interface (the default)
lythos-bearing web --port 9000 --lang tr --no-browser
lythos-bearing example -o project.bearing       # a starter project file
lythos-bearing run project.bearing -o report.pdf  # analyse, print the results, write a report
lythos-bearing study project.bearing -o samples.csv

run and study read the same .bearing file the interface saves, so a case set up in the browser can be re-run unattended. The interface listens on port 8781 by default.

Inputs

• Foundation: shape (rectangle, square, strip, circle), B (diameter of a circle), L, depth Df, base tilt η, ground slope β.
• Actions at the base: V, horizontal loads along B and L, moments about both axes, and the variable share of the actions (for the Eurocode's partial factors).
• Groundwater: depth of the water table, γw.
• Soil profile, from the surface down, one row per layer: thickness, granular or cohesive, γ, γsat, c′, φ′, cu, E, ν.
• Method: the factor set, drained / undrained / whichever governs, general or local shear, and each correction switched on or off, the effective area included.
• Layered ground: averaging over the failure zone (with a depth factor), or the two-layer punching (Ks, ca/c₁) or load-spread (angle) check.
• Earthquake: kh, kv, soil inertia on or off.
• In-situ test: SPT N60, CPT qc, or pressuremeter pl, p0 and soil category; the tolerable settlement of the SPT / CPT rules.
• Rock: σci, GSI, mi, D and the rock mass unit weight; or discontinuity spacing and aperture.
• Verification: factor of safety, or EN 1997-1 DA1 / DA2 / DA3; required FS against sliding; allowable eccentricity; base friction δ/φ′.

What it computes

The expressions, their sources and their limits are in docs/theory.md.

Figures

Section with the Prandtl failure mechanism · bearing capacity factors against φ′ for every method · comparison of the methods (ultimate and allowable against the applied pressure) · the cohesion, surcharge and self-weight terms · contact pressure and effective area · capacity and factor of safety against width and against depth · the V–H failure envelope. Study figures: one-at-a-time sweep, histogram, scatter, tornado.

Reports

Choose PDF, self-contained HTML or Word in the header and press Export report…. The report carries the inputs, the geometry and stresses, the capacity of every method, the factors and terms of the governing one, the other methods, the checks, the Eurocode verification, the required width, the figures, the warnings, the method notes and — if one was run — the study, in whichever language the interface is in. All three formats are assembled from one place, so they say the same thing.

Project files (.bearing)

JSON. Save writes the inputs and the study definition; Open… reads them back. Missing entries keep their defaults.

Modules

Development

pip install -e ".[dev]"
pytest -q                 # factors against the published tables, the equation by hand, methods, engine, study, report, web, packaging
ruff check .

The tests check the factors against the published tables, the equation against hand calculations (Prandtl's 5.14·cu, a Vesić square footing term by term, the contact pressure trapezoid and triangle), each auxiliary method against its expression, the engine's checks and refusals, the report in all three formats, the input schema and its round trips, and the interface itself — the session and the HTTP layer both, so the browser is exercised without a browser.

Releasing to PyPI is described in docs/releasing.md; tools/upload_to_pypi.py does it from an editor, without a terminal.

License

MIT © 2026 Hasan Deniz Altuntaş