Inputs

Current units: SI — P in kN, B, L, z in m, stresses in kPa (≈ kN/m²).

Total load PkN

Footing width Bm

Footing length Lm

Depth range z (below footing centre)m

Start zmin

End zmax

Step Δz

Results

Enter P, B, L and a depth range (zmin to zmax with step Δz), then click Compute stress profile to see σz.

Assumes stress at depth is uniform within the enlarged area (B+z) × (L+z) and zero outside. Best suited to preliminary checks for shallow foundations.

Representative diagram

2V:1H approximate method diagram (B×L footing spreading to (B+z)×(L+z))

Theory, formulas & references

The 2V:1H method is a simplified stress distribution approach. It assumes the load spreads linearly with depth: for every 2 units vertical, it spreads 1 unit horizontally on each side (i.e., 2V:1H). Stress at depth is considered uniform over the enlarged area.

Formulas used

Given: P = total load B = footing width L = footing length z = depth below footing base (or below centre as used here) Contact pressure: q0 = P / (B · L) Approx. vertical stress at depth z: σz = P / ( (B + z) · (L + z) ) (Stress assumed uniform within (B+z)×(L+z), zero outside.)

Assumptions / limits

Approximate method (not elastic solution). Use for quick checks and preliminary design.
Uniform load on footing and symmetric spreading.
Does not capture stress concentration, rigidity effects, layered soils, or 3D elastic distribution.
For detailed design, compare with elastic solutions (Boussinesq/Fadum/Newmark) and/or numerical methods.

References (verification)

Bowles, J. E. Foundation Analysis and Design — approximate stress distribution methods.
Das, B. M. Principles of Foundation Engineering — stress distribution and approximate methods.
NAVFAC DM 7.2 (Foundations & Earth Structures) — stress distribution concepts and practical guidance.
For elastic comparison: Poulos & Davis (1974) Elastic Solutions for Soil and Rock Mechanics.

Reviewed by YourName

2V:1H Approximate Stress under Rectangular Footing