📐 Influence Lines Builder

Build the influence line for any response on a statically determinate beam — a support reaction, a fixing moment, shear at a section, or bending moment at a section. Get the beam sketch, the IL diagram with shaded areas and peak ordinates, and a key-ordinate table. Then flip to the Müller-Breslau guide.

⭐ Build an influence line for 5 EP · this is a solve-only tool (no scan) · Balance … EP

Edit

Units

Switching converts your lengths so the beam stays the same — positions in m. (IL ordinates are per unit load; a moment IL reads in m.)

Supports & Conditions

Support / Hinge

Pin + Roller = simple / overhang span · one Fixed alone = cantilever · add an Internal hinge for a compound (Gerber) beam. Keep it statically determinate — the check above confirms it. Place a support at x > 0 or set L past the right support for an overhang.

Beam

Total length L (m) — blank = fit to the right support

The beam runs from x = 0 (left end) to L; all locations are measured from the left end.

Response (what the IL is for)

Which reaction

Loads (optional)

Add loads to turn the per-unit IL into the real design effect. Leave blank to skip. Live loads are auto-placed for the worst case; dead loads stay where you set them.

Live load — moving

Concentrated P (kN)

Uniform w (kN/m)

P sits at the peak ordinate · w covers the +/− area — both the max (+) and max (−) are reported.

Dead load — fixed

Uniform w over the whole span (kN/m)

Concentrated dead loads

Influence line & results

🪵 Beam — as given updates as you type

Add two supports — the beam draws here as you type.

📈

Set the supports and pick a response on the left, then tap Build influence line for the IL diagram, key ordinates, and the maximum effect of a moving load.

📐 Influence Lines Builder

🪵 Beam — as given updates as you type

📈 Influence line

Key ordinates

Peak ordinates & areas

🏋️ Detailed solution — design effect of loads