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T BEAM DESIGN STEP 1 : GIVEN DATA Grade of Concrete
fck
Grade of Steel fy gc Unit Weight of concrete Size of the beam 300 Max +ve Bending moment of the beam M1 Max -ve Bending moment of the beam M2 Shear force of the beam F Length of the beam l Overall depth of the beam D Effective depth of the beam d Breadth of the web bw Depth of the flange df Diameter of Main Reinforcement d1 Diameter of distribution Reinforcement d2 STEP 2 : CALCULATION OF BREADTH OF THE FLANGE
2 20 N/mm 2 415 N/mm 2 25 KN/m
500 50.35
125.38 124.26 3 500 460
300 120 16 8
KN-m KN-m KN m mm mm mm mm mm mm
From IS 456:2000 Pg No 37 clause 23.1.2 Breadth of the flange bf = ((l/6)+bw+6df)
1520
mm
STEP 3 : CHECK FOR DEPTH From IS 456:2000 Pg No 70 xumax/d= From IS 456:2000 Pg No 96 clause G.1.1 c Mu lim=0.36 * (xu max /d)((1-0.42 xu max/d))b*d2*fck 125380000
0.1728
0.7984
Required Effective depth
2 6000 d d2= d Req=
0.48
2 151465.1603 mm 390 mm
Required Overall depth Provided overall depth
D Req= D=
430 mm 500 mm
Provide an effective depth Provide an overall depth depth
dp= D pro=
460
Hence
500 mm 57
STEP 4 : CALCULATION OF AREA OF REINFORCEMENT
AT MID SPAN: From IS 456:2000 Pg No 96 CASE 1 :
NUTRAL AXIS LIES WITH IN THE FLANGE Actual Bending moment of the beam M
50350000
N-mm
From IS 456:2000 Pg No 96 clause G.1.1 c Assume Xu max = X u = Df
xumax/d From IS 456:2000 Pg No 96 clause G.1.1 c Mu lim=0.36 * (xu max /d)((1-0.42 xu max/d))b*d2*fck Mu lim
0.093913 0.89043 6432640000 Mu 1
0.260869565
537919488
N-mm
M < Mu1
From IS 456:2000 Pg No 96 clause G.1.1 b Mu=0.87* fy*Ast*d((1-(Ast*fy)/(b*d*fck)) 50350000
-166083 Ast 165530
2 0.91054276 Ast
331613 553.003998 Ast1=
2 182096.3328 mm
Ast2=
2 303.6672302 mm
Ast=
2 303.6672302 mm
Area of mainReinforcement
58
CASE 2 : NUTRAL AXIS LIES OUT SIDE THE FLANGE
From IS 456:2000 Pg No 96 clause 2.2 M > Mu 1 Assume Xu =X u max = ( df/0.43)
279.0697674
xumax/d
0.606673407
calculation of moment of resistance Mu 2 Mu 2= Mu flange + Mu web Mu flange =((0.45fck(bf-bw)df(d-.5D))
276696000
N-mm
CALCULATION OF REINFORCEMENT FLANGE REINFORCEMENT M = Cuf + Cu d) Cuf =( 0.45fck(bf-bw)df
Asf =(( Cuf )/(0.87* fy)
Cuf
5490000
Cud
44860000
Asf
15205.65019
mm2
WEB REINFORCEMENT Mu web =( M - Mu flange) Mu = Mu web b= bw
-226346000
N-mm
From IS 456:2000 Pg No 96 clause G.1.1 b Mu=0.87* fy*Ast*d((1-(Ast*fy)/(b*d*fck)) -226346000 -166083 Ast 224038.79
2 24.9726 Ast
390122 -57955.7868 Ast1=
2 7810.988769 mm
Ast2=
2 -1160.38636 mm
Asw=
2 -1160.38636 mm
Area of mainReinforcement
Total area of reinforcement = Asf +As w
Ast
14045.26383
mm2
FINAL AREA OF REINFORCEMENT =
Ast
303.6672302
mm2 59
STEP 4 : CALCULATION OF NUMBER OF REINFORCEMENT: No of reinforcement =((Ast / ast)) Area of the main reinforcement =((3.14*d1^2)/4)
200.96
No of reinforcement
mm2
2
STEP 5 : CHECK FOR SHEAR STRESS ( I ) NOMINAL SHEAR STRESS
t v=((V/b*d))
tv
2 0.900434783 N/mm
tc
0.220048718 2 1 N/mm
( ii ) PERMISSIBLE SHEAR STRESS
From IS 456:2000 Pg No 73 table 19
For
100 Ast/( b*d) 0.22005
IT IS SAFE AGAINST SHEAR Assume 2 legged 8 mm diameter stirups Asv=(3.14*d2^2)/4)
100.48
mm2
Spcing of stirups Sv =((Asv*0.87*fy)/(0.4*bw)
300
mm
minimum spacing
300
mm
300
mm
Adopt spacing of stirups Assume 2 legged 8 mm diameter stirups Vs = Vu-tc b d Spacing of stirups Sv =(0.87 fy Asv d)/Vs Adopt sapcing of stirups Sv FINAL SPACING OF STIRIUPS Sv
-13740 Kn
mm 1210 mm
1214.557485
300
mm 60
STEP 5 : CALCULATION OF AREA OF REINFORCEMENT
AT SUPPORT : From IS 456:2000 Pg No 96
Actual Bending moment of the beam M
125380000
N-mm
From IS 456:2000 Pg No 96 clause G.1.1 b Mu=0.87* fy*Ast*d((1-(Ast*fy)/(b*d*fck)) 125380000
-166083 Ast 122716.31
288799
2 24.972625 Ast
43366.693 Ast1=
2 5782.317778 mm
Ast2=
2 868.2846321 mm
Ast=
2 868.2846321 mm
Area of mainReinforcement
STEP 6 : CALCULATION OF NUMBER OF REINFORCEMENT: No of reinforcement =((Ast / ast)) rod dia Area of the main reinforcement =((3.14*d1^2)/4) No of reinforcement
16 200.96
mm2
5
61
STEP 7 : CHECK FOR SHEAR STRESS ( I ) NOMINAL SHEAR STRESS
t v=((V/b*d))
tv
2 0.900434783 N/mm
tc
0.629191762 2 0.5 N/mm
( ii ) PERMISSIBLE SHEAR STRESS
From IS 456:2000 Pg No 73 table 19
For
100 Ast/( b*d) 0.62919
IT IS NOT SAFE AGAINST SHEAR Assume 2 legged 8 mm diameter stirups Asv=(3.14*d2^2)/4)
100.48
mm2
Spcing of stirups Sv =((Asv*0.87*fy)/(0.4*bw)
300
mm
minimum spacing
300
mm
300
mm
Adopt spacing of stirups Assume 2 legged 8 mm diameter stirups Vs = Vu-tc b d Spacing of stirups Sv =(0.87 fy Asv d)/Vs Adopt sapcing of stirups Sv
FINAL SPACING OF STIRIUPS Sv
13740 Kn
mm 1210 mm
1214.557485
300
mm
62