Beam Design

Bending, shear, deflection & bearing per NDS Ch. 3-4.

✓ Validated4 independent tests · PDF

Design diagram — updates live with your inputs

Member & Material

Material typei

Speciesi Sawn lumber only

Gradei Sawn lumber only

Standard sectioni Pick a standard size (filtered to the chosen material type) to fill b/d, or Custom to enter them manually

Width b (in)i Actual (dressed) width

Depth d (in)i Actual (dressed) depth

Number of pliesi Repetitive members for Cr

Member spacing (in)i For repetitive-member Cr

Geometry & Supports

Span L (ft)i Clear/effective span

Supportsi Managed by the supports editor; add reaction points for a continuous beam (entries x_ft,pin|fixed). Two end supports = simple span.

Left end conditioni Pinned/Roller give a vertical reaction only; Fixed resists moment; Free makes a cantilever (other end must be Fixed)

Right end conditioni

Unbraced length l_u (ft)i 0 = continuously braced (CL=1.0)

Loads

Loadsi Managed by the loads editor; entries P,lb,x,D|L|S or U,plf,x0,x1,D|L|S

Dead load w_D (plf)i

Live load w_L (plf)i Floor/occupancy live

Snow load w_S (plf)i Roof snow (CD=1.15)

Design methodi ASD (service combos, CD) or LRFD (factored combos, phi*KF*lambda)

Load durationi Sets CD

Design Assumptions

Service conditioni Sets CM

Temperaturei Sets Ct

Live defl. limit L/i

Total defl. limit L/i

Incised lumberi Yes Sets Ci

NDS 2018 / SDPWS 2015

Validation, assumptions & limitations Download validation report (PDF) ↗

This calculator is verified by 4 independent tests comparing its output against closed-form statics, NDS/SDPWS design-standard values and published worked examples. Full case-by-case results are in the PDF report.

Assumptions

Simply supported single span, uniform load, ASD combination envelope.
Sawn dimension lumber; reference values from NDS Supplement Table 4A.
Dry service (CM=1.0), normal temperature (Ct=1.0), CL=1.0 (lu=0).
CD follows the shortest-duration load in the governing combination.

Limitations

Single span only; for end fixity, point loads or load classes use the general-analysis mode (validated separately by the cantilever/fixed cases).
Deflection uses E' (creep factor Kcr not applied to the live case).
Lateral-torsional CL is exercised by the general beam validation, not here.

Results are for preliminary design and must be confirmed by a licensed engineer against the current adopted code and project-specific conditions.