Design of Base Plate & Anchor Bolt

Anchor Bolt Design ASTER BUILDING SOLUTION (P) LTD Job No.:

J-619 Client: CIDCO Building: Mumbai Metro

Date: Designed By: Checked By:

19-02-2014 M SS MS MNU

DESIGN OF BASE PLATE Detail A (node 1)

Factored Design Forces Shear Force (Fx)  Axial load (Fy) Bending Moment (M) Grade of steel Grade of Anchor Bolt Concrete Grade (fck)

kN kN kN 2 N/mm N/mm

DL+LL

DL+WL

77

145

2 54

3 22

2 58

3 90

345 Gr 8.8 40

2

Geometric properties Web Size Flange Depth Bolts Dia No. Of Bolts (n)

mm mm mm

400 40 0 x1 x12 2

Plate Thickness (t) Pitch (p) guage (g) Edge Distance Embed Length (Le)

mm mm mm

36 140 96 50 850

300 30 0 x2 x20 0

32 12

mm

Plate Length 'L' Plate Width 'W'

: :

O.K  O.K  O.K 

650 mm 500 mm

Check for capacity of bolts Sd²

= 2x140²+2x270²+4x410²

857400 8574 00 mm^ mm^4 4 Maximum Tension in extreme extreme Bolt= 390X10^3x410/857400 390X10^3x410/857400 186. 18 6.5 5 kN

=

Max Tension due to Axial Force ( Fy/n )

:

Shear in each Bolt ( Fx/n)

:

 Actual Allowable (kN) (kN) 186.50 26.84 213.34 323.14 12.09 207.30

Hence Safe Hence Safe

Check for thickness of Plate in Tension  P x g/ 4 : 213.34x0.096/4

Thickness of plate required ( t )

:

5.13

:

32.00

kN.m <36mm

Hence Safe

Check for Combined Tension and Shear  Actual Tension Tension  Allowable Tension

+

Actual Shear Shear Allowable Shear

(213.34 / 323.136 ) ^2+(12.09 / 207.3)^2 =

<1.0

0.44

<1.0

Hence Safe

Check for Bolt Length Bond Stress : Pullout Force resisted by square plate in tension Force resisted by bolt Length of bolt required

: : :

1.9 N/mm 56.5 kN 156.8 kN

2

Tension in bolt/(p x bolt Dia.)x Bond stress 156.8x1000/(3.14x32)x1.9 821 mm

Hence Safe

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Check for capacity of bolts 77 254 258

Shear Force (Fx)  VERTICAL LOAD (downward '+'-ve) (kN) : B.M (kN-m) :

650

Try with a BASE PL. length L (mm.) : BASE PL. width B (mm.) :

500

Eccentricity, e (mm.) = 2 Max. stress on fdn. concrete, P max (N/mm ) = Min. stress on fdn. concrete, Pmin (N/mm2) =

1017 mm 8.12 -6.55

Tension Occurs in the Anchor Bolts  OK.

c : L * Pmax / (Pmax+Pmin) = a : L/2 -c/3 = e : edge distance y : L - c/3 - e =

360 205 50 480

mm mm mm mm

FT = Tension in all anchor bolts located at one side of base plate FT = (M - P x a) /y = Tension per bolt Shear per bolt

429 kN 72 kN 4 kN

Hence Safe Hence Safe

323.14 207.29

Check for thickness of Plate in Compression For Cantilever Plate Portion 2

 ALLOWABLE BEARING STRESS (N/mm ) :

N/mm

24.0

2

105

Projection of base pl. beyond column flange/gusset (a1) (mm) = Width of Plate (d1) (mm) = a1/d1 = From the Mukhanov chart, B.M., M =

96

1.09 0.12

=

1.09

.q.b

a

2

Here, q (N/mm ) =

5.76 6145 (in a 1 mm. wide plate strip) 10.90 < 36 mm., OK.

M (N-mm) = treqd (mm.) =

P y =

254 kN. M = 258.211153903157 105 mm. t= 36 mm. Pmax = 8.12 N/mm2 a

L = 650 mm.

For Mid Span Portion Length of the plate portion, b (mm) = Width of the plate portion, a (mm) = From the Mukhanov chart,

133 244 a/b =

(two stiffeners in between)

1.83 0.130

= B.M., M =

.q.b

a

2

Here, q (N/mm2) = M (N-mm) = treqd (mm.) =

3.28 7598 (in a 1 mm. wide plate strip) 12.1 < 36 mm., OK.

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