Rischio
Start free

Footing design software

Describe the footing. Rischio sizes it, calculates it, and shows its work.

Column and strip footings under vertical, horizontal and eccentric loads, checked for bearing capacity, eccentricity and settlement, with the calculation report ready to hand in. Describe the footing to the agent, or enter it yourself.

Design a footing, freeHow it calculates

Free, no card needed.

Your agent is working on this model
your agent · rischio

›

Or draw it yourself.

The same editor the agent works in. Pick a model, change a number and calculate: the engine answers right here.

What it checks.

Every check with its rule and its limit, Rischio's defaults. In the studio, each result opens into its equation, with your numbers in it.

How it calculates, step by step
CheckLimit

Bearing capacity

The ground under the footing giving way

FS=quqmaxFS = \frac{q_u}{q_{max}}

≥3.0\ge 3.0

Eccentricity along the width

The load inside the middle third, across the width

eBe_B

≤B6\le \frac{B}{6}

Eccentricity along the length

The load inside the middle third, along the length

eLe_L

≤L6\le \frac{L}{6}

Settlement

The footing's elastic settlement, at its centre

SeS_e

≤25 mm\le 25 \text{ mm}

What you can model

  • Square, rectangular and strip footings
  • Vertical and horizontal load
  • Moments in both directions
  • Layered soil
  • Water table at any depth
  • Embedment depth

How it's calculated

  • Bearing capacity by the general equation, with shape, depth and inclination factors
  • The effective area B′ × L′ for an eccentric load
  • Linear contact pressure from the load and both moments
  • Elastic settlement at the centre, with the strata's averaged stiffness

The calculation report, ready to sign.

This is the one for the model the editor opens on, as the studio makes it. Read through it.

  • The checks' summary first, each with its margin
  • Every section with its equations and the values they take
  • The assumptions and warnings at the end, no small print

As PDF and Word, with your letterhead, in Professional.

Your engineering firmYour address · your license number

Calculation report

Model
Column footing
Analysis
Footing
Date
15 October 2026
Units
SI · kN, m, kPa

1Summary

The model satisfies all 4 checks.

CheckValueLimitMarginResult
Bearing capacity6.77 ≥ 3.00 +126 %OK
Eccentricity along the width0.000 m≤ 0.208 m+100 %OK
Eccentricity along the length0.000 m≤ 0.333 m+100 %OK
Settlement0.005 m≤ 0.025 m+79 %OK

Limits are Rischio's defaults.

2Model

V = 93.9 kN
Figure 1. Section of the model.

Footing

FootingFooting · Rectangular

Shape Rectangular
Width BB1.25 m
Embedment depth DD0.700 m
Length LL2.00 m

Soil

γ\gammakN/m³γsat\gamma_\mathrm{sat}kN/m³c′c'kPaφ′\varphi'°EEkPaν\nu
Silty clay17.5018.505.0020.008000.00.350

γ\gamma Unit weight · γsat\gamma_\mathrm{sat} Saturated unit weight · c′c' Cohesion · φ′\varphi' Friction angle · EE Elastic modulus · ν\nu Poisson's ratio

Water

Water tableWater table · depth below ground

Depth zwz_\mathrm{w}1.00 m

Loads

Column loadLoad · on the footing

Vertical load VV93.90 kN
Horizontal load HH0.000 kN
Moment along the width MBM_B0.000 kN·m
Moment along the length MLM_L0.000 kN·m

3Loads and geometry

Vertical load

VV = 93.90 kN

Horizontal load

HH = 0.000 kN

Eccentricity along the width

eB=MB/V=0.000  m\begin{aligned} e_B &= M_B / V \\ &= 0.000\;\text{m} \end{aligned}

where VV = 93.90 kN

Effective width

B′=min⁡(B−2eB,  L−2eL)=1.25  m\begin{aligned} B' &= \min(B - 2 e_B,\; L - 2 e_L) \\ &= 1.25\;\text{m} \end{aligned}

where BB = 1.25 m, eBe_B = 0.000 m, LL = 2.00 m, eLe_L = 0.000 m

Eccentricity length

eL=ML/V=0.000  m\begin{aligned} e_L &= M_L / V \\ &= 0.000\;\text{m} \end{aligned}

where VV = 93.90 kN

Effective length

L′=max⁡(B−2eB,  L−2eL)=2.00  m\begin{aligned} L' &= \max(B - 2 e_B,\; L - 2 e_L) \\ &= 2.00\;\text{m} \end{aligned}

where BB = 1.25 m, eBe_B = 0.000 m, LL = 2.00 m, eLe_L = 0.000 m

Load inclination

β=arctan⁡(∣H∣/V)=0.000  °\begin{aligned} \beta &= \arctan(|H| / V) \\ &= 0.000\;\text{°} \end{aligned}

where HH = 0.000 kN, VV = 93.90 kN

4Bearing capacity

37.6 kPa37.6 kPa
Figure 2. Contact pressure under the footing.

Overburden at the base

q=σv′(Df)=12.25  kPa\begin{aligned} q &= \sigma'_v(D_f) \\ &= 12.25\;\text{kPa} \end{aligned}

Effective unit weight under the base

γ′ (average from Df to Df+B, B the shorter side)=10.80  kN/m3\begin{aligned} &\gamma' \text{ (average from } D_f \text{ to } D_f + B \text{, } B \text{ the shorter side)} \\ &= 10.80\;\text{kN/m}^{3}\text{} \end{aligned}

Ultimate bearing capacity

qu=cNcFcsFcdFci+qNqFqsFqdFqi+12γ′B′NγFγsFγdFγi=254.4  kPa\begin{aligned} q_u &= c N_c F_{cs} F_{cd} F_{ci} + q N_q F_{qs} F_{qd} F_{qi} + \tfrac{1}{2} \gamma' B' N_\gamma F_{\gamma s} F_{\gamma d} F_{\gamma i} \\ &= 254.4\;\text{kPa} \end{aligned}

where qq = 12.25 kPa, γ′\gamma' = 10.80 kN/m³, B′B' = 1.25 m, NcN_c = 14.83 , NqN_q = 6.40 , NγN_\gamma = 5.39 , FcsF_{cs} = 1.27 , FqsF_{qs} = 1.23 , FγsF_{\gamma s} = 0.750 , FcdF_{cd} = 1.21 , FqdF_{qd} = 1.18 , FγdF_{\gamma d} = 1.00 , FciF_{ci} = 1.00 , FqiF_{qi} = 1.00 , FγiF_{\gamma i} = 1.00

Maximum contact pressure

qmax=VA(1+6eBB+6eLL)=37.56  kPa\begin{aligned} q_{max} &= \frac{V}{A} \left(1 + \frac{6 e_B}{B} + \frac{6 e_L}{L}\right) \\ &= 37.56\;\text{kPa} \end{aligned}

where VV = 93.90 kN, BB = 1.25 m, eBe_B = 0.000 m, LL = 2.00 m, eLe_L = 0.000 m

Minimum contact pressure

qmin=VA(1−6eBB−6eLL)=37.56  kPa\begin{aligned} q_{min} &= \frac{V}{A} \left(1 - \frac{6 e_B}{B} - \frac{6 e_L}{L}\right) \\ &= 37.56\;\text{kPa} \end{aligned}

where VV = 93.90 kN, BB = 1.25 m, eBe_B = 0.000 m, LL = 2.00 m, eLe_L = 0.000 m

Check · Bearing capacity

FS=quqmax=6.77   ≥3.00 \begin{aligned} FS &= \frac{q_u}{q_{max}} \\ &= 6.77\,\text{} \; \ge 3.00\,\text{} \end{aligned}

margin +126 %

where quq_u = 254.4 kPa, qmaxq_{max} = 37.56 kPa

OK

5Eccentricity

Check · Eccentricity along the width

eB≤B6eB=0.000 m  ≤0.208 m\begin{aligned} e_B &\le \frac{B}{6} \\ e_B &= 0.000\,\text{m} \; \le 0.208\,\text{m} \end{aligned}

margin +100 %

where eBe_B = 0.000 m, BB = 1.25 m

OK

Check · Eccentricity along the length

eL≤L6eL=0.000 m  ≤0.333 m\begin{aligned} e_L &\le \frac{L}{6} \\ e_L &= 0.000\,\text{m} \; \le 0.333\,\text{m} \end{aligned}

margin +100 %

where eLe_L = 0.000 m, LL = 2.00 m

OK

6Settlement

Depth of influence

H=min⁡(Df+5B,profile)=6.95  m\begin{aligned} H &= \min(D_f + 5B, \text{profile}) \\ &= 6.95\;\text{m} \end{aligned}

Average elastic modulus

Es=ΣEihi/Σhi=8000.0  kPa\begin{aligned} E_s &= \Sigma E_i h_i / \Sigma h_i \\ &= 8000.0\;\text{kPa} \end{aligned}

Average Poisson's ratio

μs=Σμihi/Σhi=0.350  \begin{aligned} \mu_s &= \Sigma \mu_i h_i / \Sigma h_i \\ &= 0.350\;\text{} \end{aligned}

Shape factor

IsI_s = 0.618

Depth factor

IfI_f = 0.807

Elastic settlement

Se=q0(αB′)1−μs2EsIsIf=0.005  m\begin{aligned} S_e &= q_0 (\alpha B') \frac{1 - \mu_s^2}{E_s} I_s I_f \\ &= 0.005\;\text{m} \end{aligned}

where EsE_s = 8000.0 kPa, μs\mu_s = 0.350 , IsI_s = 0.618 , IfI_f = 0.807

Check · Settlement

Se≤25 mmS=0.005 m  ≤0.025 m\begin{aligned} S_e &\le 25 \text{ mm} \\ S &= 0.005\,\text{m} \; \le 0.025\,\text{m} \end{aligned}

margin +79 %

where SeS_e = 0.005 m

OK

7Notes

  1. Settlement is the immediate (elastic) component only; consolidation settlement of clays is not included.

Validated against recognized references.

Rischio is checked against worked examples from recognized engineering references. The same inputs give the same answers, and where they differ, it says why.

ExampleReferenceRischioDifference
Strip footing →
Allowable load per metre, FS 3621 kN/m622 kN/m+0.1 %
Square footing, water table →
Allowable load, FS 3667.2 kN666.9 kN0.0 %
Eccentric strip footing →
Ultimate load per metre5 260 kN/m5 261 kN/m0.0 %
Elastic settlement →
Settlement at the centre12.4 mm12.6 mm+1.6 %

Learn more.

Questions, answered.

Which footings can it check?

Square, rectangular and strip footings, with a vertical and a horizontal load and moments in both directions, on layered soil with the water table at any depth.

Which safety factors does it use?

Bearing capacity ≥ 3.0 against the maximum contact pressure, the load inside the middle third both ways (e ≤ B/6, e ≤ L/6) and settlement ≤ 25 mm. They are Rischio's defaults, each result with its margin.

How is the bearing capacity calculated?

With the general bearing capacity equation: the factors Nc, Nq and Nγ with shape, depth and inclination factors, on the effective width and length when the load is eccentric. The strength is the stratum the footing rests on; the strata above add their weight.

Does it include consolidation settlement?

No: it calculates the elastic settlement, and the report says consolidation isn't included.

Does it design the concrete?

No. It checks the ground under the footing; punching shear and reinforcement are outside it.

What does the agent do, and what does the engine do?

The agent turns your words into a model and edits it. The engine, the same one behind the editor, does every calculation: no number comes from the agent. You review the model, open every equation and sign the report.

Is it free?

The Free plan has all four tools and up to 3 models. Professional, $49 a month, adds unlimited models, the report as PDF and Word with your letterhead, and your own agent through MCP. Every account starts with 14 days of Professional, no card needed.

What will you design today?

Describe it in a sentence. Rischio builds it, calculates it, and shows you every step.

›Size a strip footing for 180 kN/m on medium dense sand.

Start designing, free14 days of Professional, no card needed