As per IS 456: 2000 for $\mathrm{M} 20$ grade concrete and plain barsin tension the design bond stress $\tau_{b d}=1.2$ MPa.Further, IS 456: 2000 permits this design bond stress value to be increased by $60 \%$ for HSD bars. The stress in theHSDreinforcing steel barsin tension, $\sigma_{s}=360 \mathrm{MPa}$. Find the required development length, $L_{d},$ for HSD barsin terms of the bar diameter, $\phi$.
As per IS 456: 2000 for $\mathrm{M} 20$ grade concrete and plain barsin tension the design bond stress $\tau_{b d}=1.2$ MPa.Further, IS 456: 2000 permits this design bond stress value to be increased by $60 \%$ for HSD bars. The stress in theHSDreinforcing steel barsin tension, $\sigma_{s}=360 \mathrm{MPa}$. Find the required development length, $L_{d},$ for HSD barsin terms of the bar diameter, $\phi$.