Beam design
1- Data
L=3000mm
Dead load=6KN/m
Live Load=8KN/m
Finished load=0.75KN/m
Wall Support=230Mm
Concrete grade=M20, Steel grade=fe415
2- Efectve span of beam
Effective Span =c/c of the support
= 3230 mm
3- Size of beam
Effective depth=Span/12
=269.16mm , Say 270mm
Breadth=1/2d =135mm
Clear cover=25mm,Use 16 mm ø
D=303 mm, Say 310 mm
D=310mm
d = 277mm, Say 280mm
d=280mm
4- Load calculations
Self Weight =1× 0.31× 0.135× 25=1.046KN/m
Live Load = 8KN/m
Dead Load =6KN/m
Finished load =0.75KN/m
T0tal Load =15.796KN/m
Factored Load =23.694KN/m, Factored BM=Wl2/8 = 30.89KN/m
5- To get AST
Ast(Required) = 388.33mm2
Numbers of rods = 2nos
Provide 2nos of 16mmø rods
6- Check for minimum and maximum AST
ASTmin=(0.85/Fy) bd =77.421mm2
ASTmax=0.04 bd=1512mm2
7- Check for shear
Nominal shear stress < permissible shear stress
ڂv =K ڂc ڂ & v=Vu/bd
Vu=38.26KN , ڂv=1.012N/mm2
Permissible shear stress (K ڂc)
100Ast/bd=1.026N/mm2
Refer From Table 19 for I.S. 456
ڂc = 0.625, ڂcmax=2.8 N/mm2
ڂ v > ڂc > ڂcmax
K ڂc=1×0.625=0.652N/mm2
8- Shear reinforcement
Vus =Vu – ڂcbd
Vus =14.625× 103 N
Provided 8mmø rods @ 2 legged Stirrups
1) Sv= ( 0.87 Fy Asv d/ Vus)
=694.41mm, Say 690 mm
2) Sv= ( 0.8 7 Fy Asv / bd)
=96.01mm < Say 100mm
3) 0.75 d= 210mm
4) 450mm
Provide 8mmø rods & 2 Legged Stirrups @ 100mm c/c
9- Check for deflection
FS=O.58 fy
Fs=240.7N/mm2 [M.F=2, BV=20]
Effective depth=Span/(BV×MF)
=80.75mm
80.75mm < 280mm
Hence it is safe
