Sheet1DESIGN OF DOG LEGGED STAIRCASEFloor BeamDataInternal DimensionsLength=4.9mWidth=2.6mFloor Height=3mFck=20N/mm2Fy=415N/mm2Riser=150mmTread=300mm4900Landing width=1200mmmmEffective Span=5.1mDOWNUPHeight of each flight=1.5mNo. of risers in each flight10NosNo. of Tread in each flight9NosDesign1200 mmd=161mm RequiredD=175mmMid Landing Beamd=154mm2600mmLoadsDL of waist slab=4.375kN/m2PLANDL on horizontal area=4.89kN/m2DL of steps=1.875kN/m2LL=3kN/m2FF=1.5kN/m2Total load=11.27kN/m2Ld = 570 mmFactored load=16.9(of one flight)BM and SFMu=55kN-mVu=43kN300d from BM consideration141mmmmY8 @ 270 mm C/C (Distribution Reinforcement)k=2.3170Y12@96 mm C/Cpt=0.763%(Main Reinforcement)Ast=1175mm2175 mm175 mmMain ReinforcementDia=12mmDETAILINGSpacing=96mmDistribution SteelAst=185mm2Dia of bar=8mmSpacing=270mmDevelopment LengthLd=Ld = ( x s) / (4 x Tbd)Therefore, Ld=564mmProvide, Ld=570mmValues of Tbd Design bond stress N/mm21.92Grade of concrete250415201.21.92251.42.24301.52.4351.72.72401.93.04 = Dia of bar=12mms = 0.87 x fy=361.05Tbd = Design bond stress N/mm2 =1.92

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