IS 2502 : 1969Code of Practice for Bending and Fixing of Bars for Concrete Reinforcement

IS 2502:1969 is the code of practice for bending and fixing of bars for concrete reinforcement — it specifies bend deductions, hook allowances, minimum bend radii, and cutting length calculations used in every bar bending schedule (BBS) in India.

You reference IS 2502 for: - Preparing BBS for any RCC project (slab, beam, column, foundation) - Calculating cutting length for bent bars (L-bars, U-bars, stirrups, links, chairs) - Specifying minimum bend radius for site bending - BOQ preparation — total rebar tonnage - Reviewing contractor BBS for accuracy - Training site fabricators on standard shapes

Pair with: - IS 456:2000 — Clause 26.2.2 specifies minimum bend radius and hook details - IS 1786:2008 — TMT bar material properties; bend test per IS 1786 Clause 9 verifies the bar can withstand IS 2502 specified bends - IS 13920:2016 — seismic detailing requires 135° hooks on all hoops / stirrups (not 90° hooks from IS 2502) - IS 5525 — layout of anchor bolts and fasteners (for steel-to-concrete connections)

Typical BBS shapes per IS 2502: - Straight bar (Shape 00): simple cutting, no bends - L-bar (Shape 01): one 90° bend at end - U-bar (Shape 02): two parallel bent ends, common for stirrup links - Crank bar (Shape 03): 45° or 30° crank for bent-up bars in slabs - Stirrup / Link (Shapes 04-09): rectangular, square, diamond, trapezoidal for beams and columns - Chair / Spacer (Shape 10): to maintain cover - Helix (Shape 11): for circular columns

When you bend a straight bar, it actually gets shorter than the sum of straight segments. This is because the bar bends around a radius, and the 'corner length' along the neutral axis is less than the two external dimensions added.

IS 2502 specifies bend deductions per Table 1 (or use direct formula):

For 90° bends: Deduction = 2d (where d is bar diameter, for mild steel) Deduction = 3d for TMT Fe 415/500 (IS 1786 bars have tighter minimum radius)

For 45° bends: Deduction = 0.5d (for all grades)

For 135° bends (stirrups, links): Deduction = 3d + hook allowance of 10d (to give the full 'hook' that anchors the stirrup)

For 180° hooks (U-bars, end hooks): Deduction includes full hook allowance of 10d minimum (more conservative 16d for some grades)

Minimum bend radius per IS 456 Clause 26.2.2.1: - For reinforcement: 4d (mild steel), 6d (Fe 500/550 TMT), 8d (Fe 600) - For stirrups and links: 2d (all grades, small-radius cold bend)

Practical formula for stirrup cutting length: L = 2 × (A + B) + 2 × 135° hook allowance — 3 × bend deduction × d Where A, B are the stirrup dimensions (internal or external, be consistent) and hook allowance is 10d per end.

For a 150 × 250 mm rectangular stirrup with 8 mm Fe 500: L = 2 × (150 + 250) + 2 × 10 × 8 − 3 × 3 × 8 L = 800 + 160 − 72 = 888 mm cutting length from a straight rod.

Project: 4.2 × 5.4 m simply supported one-way slab, 200 mm thick, 175 mm effective depth. Main reinforcement: 10 mm Fe 500 @ 150 c/c. Distribution: 8 mm Fe 500 @ 200 c/c.

Main bars — 10 mm, straight with 90° hook at each end (Shape 01): Clear span: 4,200 mm Anchorage at each support (IS 456 Clause 26.2.3): L_d / 3 for simply supported = ~13d = 130 mm each end 90° hook at each end: 10d = 100 mm each end Cutting length per bar = 4,200 + 2 × 130 + 2 × 100 − 2 × 3 × 10 (bend deductions) = 4,200 + 260 + 200 − 60 = 4,600 mm per bar

Number of main bars: along 5.4 m length at 150 c/c = 5,400/150 + 1 = 37 bars

Total main bar length = 37 × 4.60 = 170.2 m Weight per metre of 10 mm: D²/162.2 = 100/162.2 = 0.617 kg/m Main bar mass = 170.2 × 0.617 = 105.0 kg

Distribution bars — 8 mm, straight (Shape 00): Length per bar: 5,400 − 2 × 20 mm clear cover = 5,360 mm Number of bars: 4,200/200 + 1 = 22 bars Total length = 22 × 5.36 = 117.9 m Weight per metre: 64/162.2 = 0.395 kg/m Dist bar mass = 117.9 × 0.395 = 46.6 kg

Slab total rebar (pre-wastage): Main + Distribution = 105.0 + 46.6 = 151.6 kg

Slab area: 4.2 × 5.4 = 22.68 m² Rebar intensity: 151.6 / 22.68 = 6.7 kg/m² (reasonable for one-way slab)

BBS table for procurement: | Bar Mark | Shape | Dia | Cut Length | Qty | Total (m) | Unit (kg/m) | Mass (kg) | |---|---|---|---|---|---|---|---| | A1 | 01 (L-hook) | 10 | 4,600 | 37 | 170.2 | 0.617 | 105.0 | | A2 | 00 (straight) | 8 | 5,360 | 22 | 117.9 | 0.395 | 46.6 | | | | | | | | Total: | 151.6 |

Add 4% wastage for procurement: 158 kg. Round up to standard 12 m rod lengths.

1. Forgetting bend deductions. Inexperienced engineers sum up straight-segment dimensions to get cutting length — this over-orders rebar by 2-5%. Each bend removes 1-3d of length. For a 250-bar project, this can mean 3-5% over-order = ~100-200 kg extra rebar cost. Always apply IS 2502 Table 1 deductions.

2. Using wrong bend radius for Fe 500. IS 456 Clause 26.2.2.1 specifies minimum bend radius = 6d for Fe 500 (vs 4d for mild steel). Site fabricators using mild-steel radius (4d) on TMT bars can cause cracking at the bend — especially on larger bars (20+ mm diameter). Bend-test the specific batch before scaling up (per IS 1786 Clause 9).

3. 90° hooks on seismic stirrups. IS 13920:2016 mandates 135° hooks on every hoop and stirrup in seismic zones III-V. IS 2502 traditionally showed 90° as acceptable for ordinary structures. For seismic work, specify 135° in drawings AND in the BBS; inspect site bending to confirm compliance. This is the #1 seismic detailing defect found in site audits.

4. Splicing bars at plastic hinge zones. Related to bend detailing: IS 13920 Clause 7.5 restricts splice location. Your BBS cutting lengths must reflect this — order column bars long enough to avoid splicing at the critical top/bottom quarters. For a 3 m storey height column, full-length bars (3+ m) cost more per kg than spliced pieces but are mandatory for seismic compliance.

5. Not accounting for laps in BBS weight takeoff. IS 456 Clause 26.2.5.1 requires lap splices where bars continue. For Fe 500 in M25, lap = 50d to 57d depending on location. The BBS must add lap lengths to bar cutting, and the mass calculation must include laps — a 5% mass increase for properly-lapped frame bars is typical. Missing this under-estimates rebar quantity.

• IS 456:2000 — Clause 26.2 bends, hooks, development length, lap length
• IS 1786:2008 — TMT bar material; bend and re-bend tests verify bar's capacity to be bent per IS 2502
• IS 13920:2016 — overrides IS 2502 for seismic zones: 135° hooks required, tight hoop spacing
• IS 2502 (Part 1):1963 — the older edition, consolidated into 1969 revision
• IS 4956 — method of testing fusion-bonded epoxy-coated rebar; ensure bending does not damage coating
• IS 13620 — fusion-bonded epoxy-coated rebar specifications
• SP 34 — Handbook on Concrete Reinforcement and Detailing
• BS 8666 — UK equivalent (bar bending schedule) — sometimes referenced on international projects

IS 2502:1969 is 57 years old and shows its age. The standard was written for mild steel and OPC-only concrete; modern TMT bars (Fe 500, Fe 500D, Fe 550) with higher yield require larger bend radii than IS 2502 Table 1 suggests. Most Indian BBS software (IsoBar, Bar-Ed, STAAD BBS) has updated its bend deduction tables to reflect current IS 1786 grades — but if you compute BBS manually, use IS 1786 bend-test radii, not IS 2502 Table 1 directly.

A revision has been pending at BIS CED 2 (Cement and Concrete committee) for over a decade. Draft circulars in 2018 and 2023 proposed updates but nothing published yet. Until then, treat IS 2502:1969 as an interim reference and cross-check all bend-related provisions against IS 456:2000 Clause 26.2 which supersedes where they differ.

Common BBS software issues: - Some software defaults to 4d bend radius (mild steel) — verify this is set to 6d for Fe 500 - Wastage allowance defaults are 2-5%; actual site wastage ranges 4-8% depending on cutting practice - Lap lengths must be explicitly added — not all software does this automatically

Site QC tip: Ask the fabricator to produce a sample bent bar before mass production. Inspect for: - Cracks at the bend (indicates wrong bend radius) - Rough surface from bending tool (acceptable if no cracks) - Bend angle correctness (use protractor, not visual estimate) - Hook length (135° hooks must extend 10d past the last bend)

These 10-minute checks per batch prevent bar failures during concrete loading.