Base Plate
36
Design of base plate Project/Client S.No Calculations Refer 1 Design forces Factored Axial load Pu = 17 KN From ana Nature of axial load = Compression Factored Shear force Fy = 2 KN Dia of anchor bolts (HT bolts) = M 20 mm No of bolts = 4 Nos Grade of bolts = 8.8 Ultimate Tensile strength of bolt fu = 100 Mpa Ultimate Tesile strength of plate fcu = 250 Mpa Yield stress of plate fy = 250 Mpa Yield stress of bolt fyb = 250 Mpa Cube compressive strength of concretefck = 20 Mpa 2 Geometric properties Column section = ISMB Depth of section = 400 mm Width of flange = 140 mm Clearence of holes = 2 mm Dia of holes = Nominal dia of bolt + clea = 22 mm Minimum Edge distance = 33 mm Clause 1 Maximum edge distance = IS:800:2 = 192 mm ε = = 1 Edge distance provided = 150 mm O.K 25 25 16 450 150 150 150 50 30 100 140 200 12tε (250/fy) 1/2
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Base plate
Transcript of Base Plate
Design of base plate
Project/Client :-
S.No Calculations References
1 Design forces
Factored Axial load Pu = 17 KN From analysis
Nature of axial load = ompression
Factored Shear force Fy = 2 KN
Dia of anchor bolts (HT bolts) = M 20 mm
No of bolts = 4 Nos
Grade of bolts = 8.8
Ultimate Tensile strength of bolt fu = 100 Mpa
Ultimate Tesile strength of plate fcu = 250 Mpa
Yield stress of plate fy = 250 Mpa
Yield stress of bolt fyb = 250 Mpa
Cube compressive strength of concrete fck = 20 Mpa
2 Geometric properties
Column section = ISMB
Depth of section = 400 mm
Width of flange = 140 mm
Clearence of holes = 2 mm
Dia of holes = Nominal dia of bolt + clearen = 22 mm
Minimum Edge distance = 33 mm Clause 10.2.4
Maximum edge distance = IS:800:2007
= 192 mm
ε =
= 1
Edge distance provided = 150 mm
O.K
25 25
16
450
150 150 150
50
30
10
0
14
0
20
0
12tε
(250/fy)1/2
10
0
400
14
0
20
0
50
450
Minimum spacing of bolts (2.5 d) = 50 mm Clause 10.2.2 &
Maximum spacing of bolts (lesser of 32t or 3 = 300 mm 10.2.3
Spacing of bolt provided = 150 mm IS:800:2007
O.K
3 Check for base pressure
Bearing pressure of plate w = Pu/Ap
= 0.19 Mpa
Allowable bearing pressure = 0.6fck
= 12 Mpa
Safe
4 Check for Minimum Thickness of base plate Clause 7.4.3.1
Thickness of plate required IS:800:2007
= 1.22 mm
Thickness of plate required = 16 mm
Safe
4 Check for shear capacity of bolts Clause 10.3.3
Design shear strength of bolt, = IS:800:2007
= 32.63 KN
= 26.104 KN
Calculated shear force per bolt Vd = 0.5 KN
Safe
5 Check for bearing capacity of bolts Clause 10.3.4
Design bearing strength of bolts = IS:800:2007
=
= 0.4
= 32 KN
= 25.6 KN
Calculated bearing strength of bolt Vb = 4.25 KN
Safe
6 Check for tension capacity of bolts
ts
Vdsb Vnsb/עmb
Nominal shear capacity, Vnsb
Vnsb
Vdsb
Vdpb Vnpb/עmb
Vnpb 2.5kb d t fu
kb
Vnpb
Vdpb
t s≥√2 .5w (a2−0 .3b2 )γmo/ fy>tf
Design tension capacity of bolt =
Nominal Tensile capacity of bolt
=
= N.G Mpa
= N.G Mpa
Nominal Tensile capacity of bolt = N.G Mpa
Design tension capacity of bolt = N.G Mpa
Calculated tension per bolt T = N.G Mpa
N.G
7 Check for combined shear and tension
N.G+
N.G= N.G > 1.0
N.G N.G
N.G
Tdp Tnp/עmb
Tnp 0.9fubAn<fybAsb(עmb/עmo)
0.9fubAn
fybAsb(עmb/עmo)
Tnp
Tdp
Design of base plate
Project/Client :-
S.No Calculations References
1 Design forces
Axial load Pu = 156 KN From analysis
Nature of axial load = ompression
Bending moment about xx Mx = 0 KN.m
Bending moment about yy My = 0 KN.m
Lataral force along xx Fx = 0 KN
Lataral force along yy Fy = 0 KN
Dia of anchor bolts (HT bolts) = M 20 mm
No of bolts = 4 Nos
2 Geometric properties
Dia. Of pile = 300 mm
Width of column/pedestal = 450 mm
Depth of column/pedestal = 700 mm
Minimum spacing of piles = 750 mm
Centre to Centre distance of two adjacent pil = 750 mm
Edge projection from face of piles
(Min 100-150mm) = 150 mm
Width of pile cap = 600 mm
Length of pile cap = 1350 mm
Depth of pile cap ( assumed) = 600 mm
Clear cover to the reinforcement = 75 mm
Grade of concrete fck = 20 Mpa
Grade of Steel fy = 415 Mpa
3 Load calculations
Weight of pile cap = 12.15 KN
Additional load due to moment = 0 KN
Total load on each pile = 84.08 KN
= O.K
4 Calculation of reinforcement
a)Bending theory
Bending moment about xx = 21.44 KN.m
Design bending moment = 32.161 KN.m
Dia of Main reinforcement = 12 mm
Dia of secondary reinforcement = 12 mm
Effective depth of pile cap = 519 mm
Mu/bd2 = 0.2
pt = 0.056 %
pt,min = 0.12 %
Area of steel required = 373.68
b)Truss theory
Tension at bottom =
= 97.69 KN
Area of steel required = 270.57
Area of steel required
(max of bending & truss theory) = 373.68
No of bars required = 4 Nos
No of bars provided = 4 Nos
Area of steel provided = 452.16
5 Check for shear
a)One way shear
As per IS:2911-Part-1,
clause:5.6
As per IS:2911-Part-1,
clause:5.12.5
mm2
Pu/12ld(3l2-a2)
mm2
mm2
mm2
Percentage of steel provided = 0.145 %
ß = 0.87fy/6.89pt
= 17.42
= 0.273 Mpa Clause 40.5
Nominal shear stress ,ζv = 0.41 Mpa IS:456-2000
Shear span, av(C/C of pile/2-d/2+20% pile di = 0.18 m
Enhancement factor (2d/av) = 5.77
Modified shear strength, ζv = 1.57 Mpa
1.57>0.41
O K
b)Two way shear
Punching shear, V = 234 KN
Perrimeter of column, = 2300 mm
Punching shear stress, = 0.2 Mpa Clause 31.6.3
Permissible shear stress, = 1.118 Mpa IS:456-2000
1.1180339887499>0.2
O K
Permissible shear stress, ζc
Design of base plate
Project/Client :-
S.No Calculations References
1 Design forces
Factored Axial load Pu = 1100 KN From analysis
Nature of axial load = Tension
Factored Shear force Fy = 300 KN
Dia of anchor bolts (HT bolts) = M 36 mm
No of bolts = 4 Nos
Grade of bolts = 8.8
Ultimate Tensile strength of bolt fu = 100 Mpa
Ultimate Tesile strength of plate fcu = 250 Mpa
Yield stress of plate fy = 250 Mpa
Yield stress of bolt fyb = 250 Mpa
Cube compressive strength of concrete fck = 25 Mpa
2 Geometric properties
Column section = BUILT-UP I SECTION
Depth of section = 400 mm
Width of flange = 300 mm
Clearence of holes = 2 mm
Dia of holes = Nominal dia of bolt + clearen = 38 mm
Minimum Edge distance = 57 mm Clause 10.2.4
Maximum edge distance = IS:800:2007
= 144 mm
ε =
= 1
Edge distance provided = 160 mm
Not OK
50 50
12
500
160 180 160
10
0
50
20
0
30
0
40
0
12tε
(250/fy)1/2
20
0
400
30
0
40
0
10
0
500
Minimum spacing of bolts (2.5 d) = 90 mm Clause 10.2.2 &
Maximum spacing of bolts (lesser of 32t or 3 = 300 mm 10.2.3
Spacing of bolt provided = 180 mm IS:800:2007
O.K
3 Check for base pressure
Bearing pressure of plate w = Pu/Ap
= 5.5 Mpa
Allowable bearing pressure = 0.6fck
= 15 Mpa
Safe
4 Check for Minimum Thickness of base plate Clause 7.4.3.1
Thickness of plate required IS:800:2007
= 10.29 mm
Thickness of plate required = 12 mm
Safe
4 Check for shear capacity of bolts Clause 10.3.3
Design shear strength of bolt, = IS:800:2007
= 105.73 KN
= 84.584 KN
Calculated shear force per bolt Vd = 75 KN
Safe
5 Check for bearing capacity of bolts Clause 10.3.4
Design bearing strength of bolts = IS:800:2007
=
= 0.4
= 43.2 KN
= 34.56 KN
Calculated bearing strength of bolt Vb = 275 KN
Unsafe
6 Check for tension capacity of bolts
ts
Vdsb Vnsb/עmb
Nominal shear capacity, Vnsb
Vnsb
Vdsb
Vdpb Vnpb/עmb
Vnpb 2.5kb d t fu
kb
Vnpb
Vdpb
t s≥√2 .5w (a2−0 .3b2 )γmo/ fy>tf
Design tension capacity of bolt =
Nominal Tensile capacity of bolt
=
= 73.25 Mpa
= 289.02 Mpa
Nominal Tensile capacity of bolt = 73.25 Mpa
Design tension capacity of bolt = 58.6 Mpa
Calculated tension per bolt T = 275 Mpa
Unsafe
7 Check for combined shear and tension
75+
275= 6.863 > 1.0
34.56 58.6
Unsafe
Tdp Tnp/עmb
Tnp 0.9fubAn<fybAsb(עmb/עmo)
0.9fubAn
fybAsb(עmb/עmo)
Tnp
Tdp
