Bar Bending Schedule of Column: Worked Example
A column bar bending schedule lists the vertical bars, laps, ties and crossties by mark, each with count, cutting length and weight. In this worked 350 × 350 mm column, four 20 mm vertical bars are 4,000 mm each (3,000 mm height + 1,000 mm lap) and 21 ties of 8 mm are 1,150 mm each: 25 pieces, 49.05 kg.
A worked quantity example, not a reinforcement design. Weights use D²/162 kg/m; link bends use site approximations explained below. Reviewed 20 October 2026.
One workbook with slab, beam, column and footing sheets. Change any dimension and the counts, cut lengths, weights and diameter totals recalculate. The PDF prints these four examples.
Worked column: dimensions and scope
One 350 × 350 mm column segment, 3,000 mm high, with four 20 mm corner bars and 8 mm rectangular ties. Each vertical bar carries one 1,000 mm lap. Cover is 40 mm to the outside of the ties.
Tie centres run from 50 to 2,950 mm at 150 mm maximum spacing. The lap is a quantity allocation, not a splice position; do not splice all bars at one level. Joint ties, end confinement zones, starters and crossties are excluded.
| Input | Value | Unit |
|---|---|---|
| Scheduling height | 3,000 | mm |
| Column width | 350 | mm |
| Column depth | 350 | mm |
| Cover to outside of tie | 40 | mm |
| C1 vertical diameter | 20 | mm |
| C1 vertical count | 4 | bars |
| Allocated lap per vertical bar | 1,000 | mm |
| C2 tie diameter | 8 | mm |
| C2 maximum spacing | 150 | mm |
| First/last tie centre offset | 50 | mm |
| Nominal hook addition multiplier | 10 | d |
| Minimum nominal hook addition | 75 | mm |
| Cut-length rounding increment | 25 | mm |
Cutting lengths and bar counts, step by step
Each line puts the inputs above into one formula. ROUNDUP(x, 0) rounds up to a whole number and MAX takes the larger value. Bar counts include both end bars.
1. C1 straight length with stated lap
3000 + 1000 = 4,000 mm
2. C2 first-to-last centre distance
3000 − 2 × 50 = 2,900 mm
3. C2 spaces, rounded up
ROUNDUP(2900 ÷ 150,0) = 20 spaces
4. C2 tie count
20 + 1 = 21 bars
5. Outside link width a
350 − 2 × 40 = 270 mm
6. Outside link height b
350 − 2 × 40 = 270 mm
7. Nominal addition H per end
MAX(10 × 8,75) = 80 mm
8. Outside rectangle perimeter
2 × (270 + 270) = 1,080 mm
9. Three 90° deductions
3 × 2 × 8 = 48 mm
10. Two 135° deductions
2 × 3 × 8 = 48 mm
11. Raw approximate link length
1080 + 2 × 80 − 48 − 48 = 1,144 mm
12. Scheduled link cutting length
ROUNDUP(1144 ÷ 25,0) × 25 = 1,150 mm
The link formula is the site shortcut: outside dimensions, hook H = max(10d, 75 mm), and bend deductions of 2d per 90° and 3d per 135° bend. Rounding up adds 6 mm, which goes into the hook ends without reducing cover.
Full BBS table for the stated example
The column example totals 49.05 kg from 25 bars. Total length = count × cutting length ÷ 1,000; unit weight = D²/162 kg/m; weight = total metres × unit weight.
| Bar mark / position | Shape | Dia (mm) | No. of bars | Cut length (mm) | Total length (m) | D²/162 (kg/m) | Weight (kg) |
|---|---|---|---|---|---|---|---|
| C1Vertical, one stated lap allocation | Straight | 20 | 4 | 4,000 | 16.000 | 2.469136 | 39.51 |
| C2Rectangular tie | Rectangle, two 135° ends | 8 | 21 | 1,150 | 24.150 | 0.395062 | 9.54 |
| Example subtotal | 25 | 40.150 | 49.05 | ||||
C1: 4 × 4,000 ÷ 1,000 = 16.000 m; 16.000 × 20² ÷ 162 ≈ 39.506173 kg → 39.51 kg.
C2: 21 × 1,150 ÷ 1,000 = 24.150 m; 24.150 × 8² ÷ 162 ≈ 9.540741 kg → 9.54 kg.
Steel summary by diameter
| Diameter | Pieces | Total metres | Weight (kg) |
|---|---|---|---|
| 8 mm | 21 | 24.150 | 9.54 |
| 20 mm | 4 | 16.000 | 39.51 |
Unrounded row weights are added first, then the 49.05 kg total is rounded, so displayed rows can differ by 0.01 kg. Cutting waste is not included.
IS code checks and conventions used
The bend deductions and hook length below are site approximations; IS 2502, SP 34 and IS 13920 govern the approved bar shapes. The examples use the same marks and quantities as the BBS format and IS-code guide. A bar mark is only an identifier: IS 2502 clause 3.1 and SP 34 section 5 call for a dimensioned shape for each bar.
Dimensions
All inputs and cut lengths are in mm. Link dimensions are outside-to-outside. Cover is measured to the outer steel surface.
Do not put centreline dimensions into the outside-dimension link shortcut.
Bend deductions
Site approximations: 45° = 1d, 90° = 2d, 135° = 3d. Each closed link here has three 90° corners and two 135° hooks.
IS 2502 and SP 34 dimension each shape with its own allowances; neither gives one angle-only deduction table. Bend radius and steel type change the true value.
Hook extension / allowance
H = max(10d, 75 mm) per hook; for an 8 mm link, H = 80 mm.
10d (at least 75 mm) is the IS 13920:1993 hook extension, clauses 6.3.1 and 7.3.1. The 2017 amendment to IS 13920:2016 uses 8d (at least 75 mm). We keep 10d to match our BBS guide; use the edition your project specifies.
Approximate link length
2(a + b) + 2H − [3(2d) + 2(3d)], rounded up to the next 25 mm.
A site estimating shortcut, not a bend allowance from IS 2502. Fabricate to the approved shape and bend radius.
Bar counts
Ceiling(first-to-last centre distance / maximum spacing) + 1.
Both end bars are included. For a mesh, centre distance = overall size across the bars − 2 × cover − bar diameter. Count a bar on a shared zone boundary once.
Weight
Total length × D²/162 kg/m, kept at full precision until display.
A close approximation: 12 mm gives 0.888889 kg/m against 0.888 kg/m in IS 1786 Table 1. Bill on the basis your contract states.
Rounding and scope
Bent lengths round up to the next 25 mm; the straight lengths here already land on 25 mm. Weights show 2 decimals.
IS 2502 clause 5.1.1 and SP 34 clause 13.3.3.1 take the rounding excess into a portion named on the schedule. Waste, stock-length optimisation and bars not shown here are extra.
Sources checked
- IS 2502:1963 — clauses 3.1, 5.1.1 and Tables II–IX
Dimensioned shapes, allowances and cutting-length increments.
- SP 34:1987 — section 5 and clause 13.3.3.1
Bar marks, member schedules, sketches and the 25 mm scheduling increment.
- IS 13920:1993 — clauses 6.3.1 and 7.3.1
135° hook extension for beam and column hoops: 10d, at least 75 mm.
- IS 13920:2016, Amendment 1 (September 2017)
Reproduced BIS amendment (third-party copy): 8d, at least 75 mm, in beam clause 6.3.1(a) and column clause 7.4.1. Check the edition your project specifies.
- IS 1786:2008 — Table 1
Nominal mass per metre; differs slightly from the D²/162 approximation.
- IS 456:2000 — clauses 26.2 and 26.4
Development, laps and nominal cover; use the approved design values.
Common column BBS mistakes
Adding the same lap to two floor schedules
Assign the physical lap quantity once and record the pour/member allocation.
Assuming 50d is always the lap length
The 1,000 mm lap is an input. Read the designer's stress, bond, splice and confinement requirements.
Applying clear cover to the main-bar centre
Cover reaches the outside tie surface. Include tie and main-bar radii when locating the vertical bar centres.
Omitting joint ties or crossties
Reconcile the full elevation and section. Additional tie shapes and confinement zones require their own counts.
Use a checked BBS in your BOQ and billing
Carry BBS kilograms into the reinforcement BOQ item only after every bar on the drawings is accounted for. Keep the member, floor or pour, drawing revision, shape and checker with each schedule. For BBS from your full drawing set, get a BOQ from drawings below; for monthly BBS with measurement sheets and RA bills, use the construction billing desk.
FAQs: BBS of column
How do you prepare a column BBS?
Read the column schedule and elevation together. Separate vertical bars by diameter and cut length, allocate laps once, then list each tie/crosstie shape and spacing zone.
What is the vertical-bar cutting length here?
The exercise gives a 3,000 mm scheduling height and one 1,000 mm lap allocation, so each of the four C1 bars is 4,000 mm.
Is the column lap always 50 times diameter?
No. Although the illustrative 1,000 mm equals 50 × 20 mm, it is a stated input. Actual lap length, staggering, location and confinement need the approved design.
Why are there 21 ties?
The first-to-last tie centre distance is 2,950 − 50 = 2,900 mm. Ceiling(2,900/150) gives 20 spaces and therefore 21 ties. Equal spacing is 145 mm.
What is the tie cutting length?
Outside size is 350 − 2 × 40 = 270 mm each way. The stated shortcut gives 2(270 + 270) + 160 − 96 = 1,144 mm, scheduled upward to 1,150 mm.
Does this tie schedule satisfy ductile detailing?
No. It leaves out joint and confinement-zone ties, and its hooks use the 10d extension from IS 13920:1993. Check the edition and the zones your design specifies.
How are column starters measured?
Use their actual embedded length, bends and projection from the footing or lower pour. Give them separate marks and prevent duplicate lap or embedded-length allocation across schedules.