IS 2502 — Bar Bending

IS 2502:1963 (Reaffirmed 2009) — 'Code of Practice for Bending and Fixing of Bars for Concrete Reinforcement' is the Indian standard for bar bending, splicing, and detailing of reinforcement in RCC. Used for: bar shape codes (IS 2502 Annex), bend allowances and deductions, hook lengths, lap splice requirements (cross-referenced from IS 456). Major Indian reinforcement detailers and BBS preparers reference IS 2502 + IS 456 for all reinforcement work.

Key IS 2502 provisions: (1) Standard bar shapes and shape codes — straight, single-bend (90° L), double-bend (Z, U), specialty shapes. Each shape has a code letter (e.g., 'A' for straight, 'B' for L-bend) and dimensional formula. (2) Bend allowances — extra length needed for the bend itself; typically 4-6× bar diameter for 90° bend. (3) Bend deductions — length lost to the bend curve; for 90° bend = 2× bar diameter. (4) Hook allowances — extra length for 90° hook (8d), 135° hook (12d), 180° hook (8d). (5) Cutting length formula — sum of straight portions + bend allowances − bend deductions. (6) Lap splice requirements (cross-referenced to IS 456) — typically Ld + 30% in tension, with stagger requirement.

For a typical L-shaped rebar 1500 mm × 300 mm with 135° hook on one end (16 mm bar): cutting length = 1500 + 300 − (2 × 16) + (12 × 16) = 1968 mm. The arithmetic of every BBS depends on these IS 2502 formulas. Modern Indian BBS software (BBS Master, SoftPlus, AutoCAD Structural Detailing) implements IS 2502 + IS 456 lap rules automatically. Site engineers verify random samples against BBS calculations to catch transcription errors. The most-overlooked aspect of Indian reinforcement: shape-code documentation. Many BBS show only the bar mark and dimensions, omitting the shape code — making site verification difficult. Best practice: every BBS row includes shape code from IS 2502 Annex.