Lythos Bearing

Foundations

Bearing capacity of shallow foundations

Terzaghi, Meyerhof, Hansen, Vesić, EN 1997-1 and Skempton side by side; eccentric and inclined loads, layered ground, SPT/CPT/pressuremeter, rock, earthquake and reliability studies.

$ pip install lythosbearing

Run

lythos-bearing

Default port

8781

Python

3.10+

Version

0.1.0

Licence

AGPL-3.0

See the examples →ReferenceSource ↗

A rectangular, square, strip or circular footing on a layered soil profile, under a vertical load, horizontal loads in two directions and moments, is checked by every method an engineer is likely to be asked for, side by side. The governing method is marked; the others stay in the table for comparison.

What it computes

1. The general bearing capacity equation — the factor sets of Terzaghi (1943), Meyerhof (1963), Brinch Hansen (1970), Vesić (1973) and EN 1997-1 Annex D, and Skempton's (1951) undrained N_c; 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 B′ × L′, the contact pressure (trapezoid in the middle third, triangle outside it).
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 (as revised by Bowles) and Ménard's pressuremeter rule.
5. Rock — Hoek–Brown turned into an equivalent c′, φ′, and the CFEM discontinuity-spacing method.
6. Earthquake — the 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; the width the foundation needs.

On top of it, a parametric or reliability study sweeps any input as a range or a distribution and reports the probability of failure in bearing, sliding and eccentricity with a 95 % confidence interval and the reliability index β.

Screenshots

Results summary: six methods, the checks and the width required

Comparison of the methods: ultimate and allowable pressure

Section and Prandtl mechanism — dark theme, Turkish

Capacity and factor of safety against width

V–H failure envelope

Reliability study

Quick start

pip install lythosbearing
lythos-bearing                               # interface: http://127.0.0.1:8781/

In the 1 · Foundation and soil tab enter the footing, the actions, the water table and the soil profile, and press Analyse. Results appear under Summary, Results and Figures; the 2 · Study tab runs parametric and reliability studies. Export report… in the header writes PDF, HTML or Word.

The same from the command line:

lythos-bearing example -o project.bearing    # a starter project
lythos-bearing run project.bearing -o report.pdf
lythos-bearing study project.bearing -o samples.csv

Figures

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

Next steps

• Examples — the starter project, a width sweep, EN 1997-1 and a reliability study.
• Reference — every input, the methods, the modules and the validation.
• The same factors are used by Lythos MSEW for the bearing capacity under the wall.