Manual Beam Design

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.EFFECTIVE SPAN OF BEAM:

Effective Span =c/c of 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 & MAXIMUM AST:

AST_min=(0.85/F_y) bd =77.421mm²

AST_max=0.04 bd=1512mm²

7.CHECK FOR SHEAR:

Nominal shear stress < permissible shear  stress

ڂ_v =K ڂ_c  ڂ    & _v=V_u/bd

V_u=38.26KN ,      ڂ_v=1.012N/mm²

Permissible shear stress (K ڂ_c)

100Ast/bd=1.026N/mm²

Refer  From  Table 19 for I.S. 456

ڂ_c  = 0.625,  ڂ_cmax=2.8 N/mm²

ڂ _v      > ڂ_c    >    ڂ_cmax

K ڂ_c=1×0.625=0.652N/mm²

8.SHEAR REINFORCEMENT:

V_us  =V_u  –  ڂ_cbd

V_us  =14.625× 10³ N

Provided 8mmø rods  @ 2 legged Stirrups

1) S_v= ( 0.87 F_y  Asv d/ V_us)

=694.41mm, Say 690 mm

2) S_v= ( 0.8 7 F_y 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:

F_S=O.58 f_y

F_s=240.7N/mm²                                                                   [M.F=2,  BV=20]

Effective  depth=Span/(BV×MF)

=80.75mm

80.75mm < 280mm

Hence it is safe

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