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Civil & Environmental

Beam Lab

Statics, made visible. Slide a point load along the span (or switch on a uniformly-distributed load) and the reactions, the shear-force diagram, the bending-moment diagram and the exaggerated deflected shape all respond in real time. The reaction → shear → moment → deflection chain is exactly where statics students get lost — here you can watch the moment diagram move as you drag the load.

Shear VBending moment M

50.0

Reaction A

50.0

Reaction B

250.0

Max moment

50.0

Max shear

The method, with your numbers

Simply-supported beam statics

  1. 1

    Take moments about A to find R_B

    ΣM_A = 0 ⇒ R_B = P·a / L

    R_B = 100·5 / 10 = 50 kN

    Summing moments about A makes R_A vanish — one equation, one unknown.

  2. 2

    Vertical equilibrium gives R_A

    ΣF_y = 0 ⇒ R_A = P − R_B

    R_A = 100 − 50 = 50 kN

    The nearer support takes the bigger share — slide the load and watch the split change.

  3. 3

    Peak shear is the larger reaction

    V_max = max(R_A, R_B)

    V_max = max(50, 50) = 50 kN

    V is constant between loads and drops by P as you cross the load point.

  4. 4

    Peak bending moment (under the load)

    M_max = R_A·a = P·a·b / L

    M_max = 50·5 = 250 kN·m

    Load at midspan — this is the classic P·L/4 result, the biggest moment this load can make.

Drag any control above — every number here recalculates. Want this method for any problem? Step Sheets →

Span10 m
Point load P100 kN
Load position5 m

Slide the load across the span and watch the moment diagram and the deflected shape (dashed) respond. Max moment is at 5.0 m.

How to use this simulation

Statics, made visible. Slide a point load along the span (or switch on a uniformly-distributed load) and the reactions, the shear-force diagram, the bending-moment diagram and the exaggerated deflected shape all respond in real time. The reaction → shear → moment → deflection chain is exactly where statics students get lost — here you can watch the moment diagram move as you drag the load.

Everything runs in your browser — no sign-up, no download. Change a value and the result updates instantly, so you can build a feel for how each input shapes the outcome. It pairs with Crameleon's practice exams and step sheets when you want to go from intuition to working the problems.