How to Prepare a Bar Bending Schedule for a Beam

Beams bring together more shape codes than any other common member — straight main bars, closed-link stirrups, and sometimes cranked bars, all in one schedule. This guide walks through identifying each bar type in a typical beam and a worked example showing how they're scheduled.

The bars in a typical beam

Not to scale — illustrative only

• Bottom (main) bars. Straight bars (shape code 00) running along the tension face of the beam, carrying the main bending load at mid-span.
• Top bars. Straight or single-bent bars over the supports, where a continuous beam needs tension reinforcement at the top rather than the bottom.
• Stirrups (links). Closed rectangular links (shape code 51) spaced along the beam's length, resisting shear and holding the main bars in position — the same shape used for column ties, just sized to the beam cross-section.
• Cranked bars (where used). Some designs use a bar that steps diagonally from the bottom near mid-span to the top near a support (shape codes in the 26–29 range), following where tension reinforcement is needed as bending moment changes along the beam.

Worked example

A simply supported beam, 6.0m span, 300mm × 500mm section, 3 no. 20mm bottom bars, 10mm stirrups at 150mm centres, 25mm cover.

1. Main bar length. Beam span plus a small anchorage allowance into the supports at each end — here, 6.0m span + 2 × 50mm ≈ 6.1m.
2. Stirrup cutting length. Applies the closed-link formula (shape code 51) using the beam's width and depth (300mm × 500mm) less cover on each face — see the shape codes guide for the formula.
3. Number of stirrups. Beam span ÷ stirrup spacing, plus one: 6.0m ÷ 0.15m + 1 = 41.
4. Total length and weight. Cutting length × number of bars for each mark, then apply the weight-per-metre for the bar size.

Beams with cranked bars or top steel over continuous supports add extra bar marks on top of this, but the underlying process — shape code, dimensions, quantity, weight — stays the same for every bar.

Frequently asked questions

What bars go into a beam bar bending schedule?

A beam schedule typically includes bottom (main) bars, top bars over supports, and stirrups (closed links) spaced along the beam to provide shear capacity and hold the main bars in position. Some beams also include cranked bars that move from bottom to top steel near a support.

What shape code is used for beam stirrups?

Beam stirrups are almost always a closed rectangular link, most commonly BS 8666 shape code 51, sized to the beam's width and depth with a deduction for cover on each face.

Why are some beam bars cranked instead of straight?

Cranked bars step from the bottom of a beam near mid-span up to the top near a support, following where bending moment (and therefore the need for tension steel) shifts along the beam, which in some designs allows one bar to do the job of separate bottom and top bars.

This is an illustrative worked example, not a substitute for a checked, engineer-approved bending schedule. Always take dimensions, stirrup spacing, crank positions and bar sizes from the actual structural design.