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Load Combination Calculator

Work out load combination instantly with clear inputs, formula shown and shareable results.

About Load Combination Calculator

Limit state design checks several factored combinations because different load patterns govern different members. The four evaluated here are 1.4 D, 1.2 D + 1.6 L, 1.2 D + 1.0 L + 1.0 W and 0.9 D + 1.0 W, the last of which matters for uplift and overturning where dead load is a stabilising rather than a destabilising effect.

Formula

Strength combinations

1.4 D; 1.2 D + 1.6 L; 1.2 D + 1.0 L + 1.0 W; 0.9 D + 1.0 W

Worked example

With the default values below, Load Combination Calculator returns Governing factored load of 440.0. Change any input above and every figure here is recalculated in your browser.

Inputs used

Dead load effectminimum 0 kN
200 kN
Live load effectminimum 0 kN
120 kN
Wind load effectminimum 0 kN
80 kN

Results

Governing factored load
440.0 kN
1.4 D
280.0 kN
1.2 D + 1.6 L
432.0 kN
Governing combination
1.2 D + 1.0 L + 1.0 W

Step by step

  1. 1Values used
  2. 2Strength combinations
  3. 3Governing factored load= 440.0 kN
  4. 41.4 D= 280.0 kN
  5. 51.2 D + 1.6 L= 432.0 kN
  6. 6Governing combination= 1.2 D + 1.0 L + 1.0 W

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or compounding frequency into account.
  • Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Preliminary estimate only. Load factors and combinations must be taken from the design code adopted for the project.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Load factors and combinations must be taken from the design code adopted for the project.

Frequently Asked Questions

How is the Load Combination figure worked out?

1.4 D; 1.2 D + 1.6 L; 1.2 D + 1.0 L + 1.0 W; 0.9 D + 1.0 W. Limit state design checks several factored combinations because different load patterns govern different members.

Why is the dead load factor sometimes 0.9?

When dead load resists the action being checked, using its full value would be unsafe if the real weight is lower than assumed. The 0.9 factor is the counterweight-minimum case.

What values do I need to enter?

This calculator takes 3 inputs: Dead load effect, Live load effect, Wind load effect. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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