What is a bar bending schedule?
A bar bending schedule lists every bar in a concrete member: its diameter, number, cut length and bending shape. It is prepared with the reinforcement shop drawings and submitted to the consultant with them.
The columns
- Member and bar mark: such as footing F1 or column C3, and the bar number as on the drawing.
- Diameter: in millimetres, such as 12, 16 or 20.
- Number: bars per member multiplied by the number of repeated members.
- Cut length: the straight length before bending, including bends and laps.
- Shape: the shape code and its dimensions, to the standard adopted on the project.
- Weight: total length multiplied by the weight per metre for the diameter.
How weight is calculated
Weight per metre (kg) = diameter² ÷ 162
Example: a 16 mm bar weighs 16 × 16 ÷ 162 = about 1.58 kg per metre. With 40 bars of 6 m cut length in a member, the weight is 40 × 6 × 1.58 = about 379 kg.
Why consultants ask for it
- To check the reinforcement against the structural drawings before cutting.
- To control order quantities and reduce waste.
- To review lap and anchorage lengths and splice locations.
Mistakes we often see
- A cut length that ignores bend allowances, so the bar is short on site.
- Repeated similar members missing from the count.
- A schedule that no longer matches the drawing after the last revision.
We prepare reinforcement drawings with bar schedules in our structural shop drawing packages. See also the shop drawing checklist.
Frequently asked questions
What is a bar bending schedule (BBS)?
A list of every bar in a concrete member with its diameter, number, cut length, bending shape and weight, prepared with the reinforcement drawings and used to cut and order the steel.
How do I calculate steel weight from a BBS?
Weight per metre in kilograms equals the bar diameter in millimetres squared divided by 162, multiplied by the total bar length.
Is the BBS submitted to the consultant?
Yes, usually with the reinforcement drawings in the structural shop drawings, so it can be checked against the drawings before cutting.
