Development Length: How to Calculate Development Length?

Limit State Method (for M25 grade concrete and Fe 415 grade Steel)

Dia of bar f = 12 mm 

Stress in Bar s_s= 415 N/mm2 (for Fe 415 Steel)

 Design Bond Stress t_bd= 2.24 N/mm2 ( As per 26.2.1.1 of IS 456-2000 for deformed bars)

So for bar of f 12 mm development length (Ld)= 46 x 12= 552 mm

Working Stress Method (for M25 grade concrete and Fe 415 grade Steel)

Dia of bar f = 12 mm 

Stress in Bar s_s= 230 N/mm2 (As per table 22 , Annex-B of IS 456)

 Design Bond Stress t_bd= 1.44 N/mm2 ( For M25 grade concrete as per Table 21 of IS 456-2000 for deformed bars)

So for bar of f 12 mm development length (Ld)= 40 x 12= 480 mm