CIVILKITengineering toolsOpen beam tool

structural / field note

What does a beam quick check actually tell you?

A beam result becomes useful when the reader can tell which load case produced it, which response is being measured, and what still needs a proper design check.

Field note / structural beams

Moment, shear, and deflection are different questions.

Maximum bending moment describes the peak internal bending action for the idealised load case. Maximum shear describes the peak transverse action near the supports. Elastic deflection describes how much the beam moves under the selected stiffness assumptions.

Why the load case must stay visible

A single number without its load case is difficult to audit. A simply supported beam with a full-span UDL behaves differently from the same beam with a central point load, and a cantilever is a different boundary condition again.

The quick equations

For a full-span UDL w and central point load P over span L: Mmax = wL²/8 + PL/4 and Vmax = wL/2 + P/2. With constant E and I, the elastic midspan deflection is 5wL⁴/(384EI) + PL³/(48EI).

What remains outside the screen

  • Load combinations, self-weight, lateral stability, shear capacity, vibration, and connection behaviour.
  • Actual support stiffness and restraint, which may not be perfectly simple or fixed.
  • Material non-linearity, cracking, local buckling, fatigue, and code-specific serviceability limits.

Run the simply supported beam check