structural / beams

Simply supported beam with partial UDL zones.

Combine one or two rectangular uniform-load zones anywhere on a simply supported span and screen the reactions, shear range, and governing positive bending moment.

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Build common partial-load variants from two zones.

Each zone is a downward UDL with intensity wi, start ai, and end bi. The zones may be central, at an end, at both ends, separated, touching, or overlapping.

Governing equations

For zone i, Wi = wi(bi - ai) and its centroid is x̄i = (ai + bi)/2. Equilibrium gives RA = ΣWi(L - x̄i)/L and RB = ΣWi - RA. Within each interval, shear changes linearly and the critical moment is checked at zone boundaries and zero-shear positions.

Classic variants covered

This parameterised page covers a central partial UDL, an end partial UDL, partial UDLs at both ends, two separated zones, and overlapping uniform-load zones. Overlap means the intensities are added.

Keep it as a statics load-case screen.

  • Use positive L; keep every ai and bi between the supports with bi ≥ ai.
  • Loads are downward and non-negative; a zero-intensity zone is ignored.
  • Deflection, stress, self-weight unless entered, load factors, stability, and code limits are not checked.
  • This is elastic-load analysis terminology, not member or connection design.