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Calcs.com
IBC 2009-2024, IRC 2009-2024, ASCE 7-10 - 7-22United States

Beam Analysis with Load Combinations (LRFD)

Enter unfactored dead, live, snow, wind, and seismic loads and the calculator automatically generates all governing LRFD combinations per IBC and ASCE 7-10 through 7-22, delivering factored Mu and Vu for every combination. Support reactions from the governing combination link to connected column and footing calculations so the whole load path updates when you change any input.

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What it calculates

Enter unfactored loads and the calculator generates all governing LRFD combinations per IBC/ASCE 7, then runs FEA to produce factored demands for strength-level checks. Identify the governing combination instantly without manual load factor work.

Code standards

  • IBC 2009-2024, IRC 2009-2024, ASCE 7-10 - 7-22

How it calculates

The LRFD Beam Analysis calculator passes all typed loads through the FEA solver against all ASCE 7 LRFD strength combinations, returning envelope factored demands for each result type.

Load input and combination generation

Loads are entered by type: D, L, Lr, S, R, W,dn, W,up, Ev, and Eh. The calculator applies LRFD strength-level factors from ASCE 7 Section 2.3 to each load type and generates 16 strength combinations. For example:

  • 1.4D
  • 1.2D + 1.6L + 0.5Lr (or S or R)
  • 1.2D + 1.6S + f1·L + 0.5Lr
  • 1.2D + 1.0W,dn + f1·L + 0.5Lr
  • 0.9D + 1.0W,up
  • 0.9D - 1.0Ev + 1.0Eh

The companion factor f1 on live load is 1.0 for most occupancies, reduced when LLR is enabled.

Strength envelope

The FEA solver runs each combination and envelopes to find:

  • Mu+ = max factored positive moment across all strength combinations
  • Mu- = max factored negative moment (hogging)
  • Vu = max factored |shear|
  • Max factored reaction at any support

The governing combination label is reported alongside each demand.

Serviceability demands

Service-level deflections are tracked separately under unfactored or partially factored service combinations: short-term (live/snow/wind), long-term (D + L + Lr with creep), and simplified DL+(LL or SL). Deflection span ratios are reported.

The calculator does not perform member capacity checks - it delivers LRFD factored demands for direct use in steel, concrete, or CFS design calculators.

Related calculators

Beam Analysis→Beam Analysis→Beam Analysis with Load Combinations (ASD)→

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Frequently asked questions

What load combinations does the LRFD Beam Analysis calculator use?
All LRFD strength combinations from ASCE 7-10 through 7-22, Section 2.3. The standard set includes 1.4D, 1.2D + 1.6L + 0.5Lr, 1.2D + 1.6S + f1·L, 1.2D + 1.0W,dn + f1·L + 0.5Lr, 0.9D + 1.0W,up, and seismic combinations such as 0.9D - 1.0Ev + 1.0Eh. The companion live load factor f1 is 1.0 or the LLR-reduced value.
What are the key inputs?
Beam geometry and support configuration, plus unfactored load magnitudes by type - dead (D), live floor (L), roof live (Lr), snow (S), rain (R), wind (W), and seismic (Ev, Eh). Distributed loads are entered as area intensities (psf) with a tributary width; point loads are entered in kips.
What results does it output?
Governing factored positive moment Mu+ and negative moment Mu- (kip·ft), governing factored shear Vu (kip), maximum factored reaction (kip), and three serviceability deflection demands: short-term, long-term, and simplified DL+(LL or SL). A full combination table shows which combination governs each result.
What is the difference between this calculator and the ASD version?
LRFD combinations (ASCE 7 Section 2.3) apply strength-level load factors (1.2D, 1.6L, etc.) to produce ultimate factored demands Mu and Vu, which are compared to reduced nominal capacities φMn and φVn. ASD combinations (Section 2.4) produce lower combined demand values for comparison against allowable capacities. Choose LRFD when your member design calculator (steel, concrete, CFS) uses LRFD.
Does the calculator support live load reduction?
Yes - live load reduction per ASCE 7-16 Cl 4.7 is an optional toggle. The companion live load factor f1 is automatically adjusted to the LLR-reduced value when enabled.
Does this calculator support load linking with column and footing calculations?
Yes - support reactions from the governing LRFD combination link directly to connected column or footing calculations in the same project. Change any unfactored load and all linked calculations update automatically - no manual reaction re-entry.

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