Isolated Foundation — Soil Pressure Calculator

1 — Applied Loads at Column Base

ULS factored loads. Working loads for soil pressure are derived with EN 1990 Annex A1, Table A1.2 Set C (γ_G,sup = 1.0).

NkNaxial force (compression)

MkN·mbending moment at column base

FkNhorizontal shear at column base

γ_G,sup—EN 1990 A1.2 Set C

2 — Foundation Geometry

Footing Base

Lmbase length (along moment)

Wmbase width

tmbase slab thickness

fmdepth to top of base slab

Pier / Column Pedestal

lmpier length (along X)

wmpier width (along Z)

hmpier height

3 — Material Properties

γ_fillkN/m³unit weight of fill

γ_conckN/m³unit weight of concrete

4 — Self-Weight Calculation

V_fill = (L × W − l × w) × f —m³

G_fill = V_fill × γ_fill —kN

V_conc = L × W × t + l × w × h —m³

G_conc = V_conc × γ_conc —kN

Resultant Loads at Foundation Base

N_base = γ_G × (G_fill + G_conc) + N —kN

M_base = M + F × (t + h) —kN·m

5 — Eccentricity Check

e = M_base / N_base —m

L/6 = (core limit) —m

L/2 = (half-length) —m

6 — Overturning Check

M_stab = N_base × L/2 —kN·m

OTR = M_stab / M_base —— —

7 — Maximum Soil Pressure

Small Eccentricity (e ≤ L/6) — Trapezoidal Distribution

q_max = N_base/(L·W) + 6·M_base/(W·L²) —kPa

q_min = N_base/(L·W) − 6·M_base/(W·L²) —kPa

Large Eccentricity (e > L/6) — Triangular Distribution with Uplift

Y = 3 × (L/2 − e) active base length —m

q_max = 2·N_base / (W × Y) —kPa

q_min = 0 (uplift / tension — not resisted) 0.00kPa

q_max — Max Soil Pressure

—

kPa

q_min — Min Soil Pressure

—

kPa

OTR — Overturning Ratio

—

M_stab / M_base (min ≥ 2.0)

Reference: EN 1997-1:2004 — Eurocode 7: Geotechnical design — Part 1: General rules | EN 1990:2002 — Eurocode: Basis of structural design — Annex A1, Table A1.2 (Set C)

A — Foundation Cross-Section & Geometry

Figure 1 — Foundation cross-section (elevation view along moment direction) — interactive, redraws on input change

B — Soil Pressure Diagram

Figure 2 — Soil contact pressure distribution at base — interactive, redraws on input change

Reference: EN 1997-1:2004 — Eurocode 7: Geotechnical design — Part 1: General rules

EVO DESIGN

EVO DESIGN