Base Plate Thickness

BASE PLATE SIZING

Material Specifications

Base Plate Steel 248 MPa Base Plate Steel 400 MPa

Plinth Concrete 28 MPa

Base plate bearing interface cantilever m = (N - 0.95d)/2

= 32.3 mm

n =

= 48.4 mm

Yield line theory cantilever n' =

Note : Conservatively calculated assuming = 74.9 mm no stiffner plate.

Check for Interference

F_y = F_u = f_c' =

(B - 0.8b_f)/2 √d.b_f / 4 Assumed Base Plate Bending Plane

without stiffener plates.

m 0.95d m N 2 x f = F d f f bf cc B 0 .8 bf n n

= 110 mm (B - cc)/2 = 60 mm Minimum of (f - tstiff)/2 - w, (cc - tw)/2 - w = 73.5 mm 160 mm (Bp - cc)/2 = 160 mm

Base Plate Edge Distance along Length e_L = (N - f x (N_AB/2 - 1))/2 Base Plate Edge Distance along Length e_B =

Wrench Clearance from c/L of A.B. e_WR=

Anchor Bolt Edge Distance along Length e_ABL = (L_p - f x (N_AB/2 - 1))/2 Anchor Bolt Edge Distance along Width e_ABB =

BASE PLATE DESIGN

Base Plate Design Forces from Column Support Reactions

For the critical load comb. L/C 213 forces @ column support are;

Axial Load 'Pu' = -187.1 KN +ive value implies compression & -ive implies tension.

Check for Concrete Bearing

Design Bearing Strength =

= (for partial area of concrete support s/t √A2/A1 < 2)

where = N x B = 120000

= = 250000

2679.48 KN Check for Plate Thickness in Axial Compression

Uniform pressure over base plate q = N/A

The largest base plate cantilever 'c' = Maximum of m, n & n' = 74.9

For the yielding limit state, the required minimum thickness of the base plate can be calculated as follows (AISC,2005d) >= N/A mm where a = 163 mm b = 122.25 mm a/b = 1.333 0.591 N/A Check for Plate Thickness in Axial Tension

46.775 KN As per Clause #J.8 of AISC360-05,

ф_c.P_p ф_c = 0.65 as per Section 9.3 of ACI318-08. 0.65 x (0.85 x fc' x A₁ x √A₂/A₁)

A_{1 mm}2

A₂ L_p x B_{p mm}2

Therefore the concrete bearing strength ф_c.P_p =

N/mm2 For the base plate without stiffener plates

t_p(req) >= c √2Pu/(ф_bF_yBN) Ф_b = resistance factor for bending in LRFD, 0.9

For the base plate with stiffener plates

β₁ =

Therefore the bending stress σ_max = N/mm2

The base plate in bending is reinforced by means of stiffener plates providing fixed edge conditions on 3 sides.

However conservatively analyzing the base plate with Roark's formulae applicable to simply-supported plate s/t concentrared load.

where

21.6 mm a = 163 mm b = 122.25 mm

ν = 0.3 (Poissons ratio for isotropic steel) Therefore a/b = 1.333 21.60 mm β = 0.74 85.99 < 0.9Fy, hence OK Radius of nut r_o = r_o' =

COLUMN BASE BOUNDARY CONDITION : PINNED DIMENSIONS Column Dimensions Column Section = W14x61 Column Depth 'd' = 353 mm 254 mm 16.4 mm 9.5 mm Allround weld size 'w' = 8 mm Base Plate Dimensions

Base Plate Length 'N' = 400 mm Base Plate Width 'B' = 300 mm

25 mm

4 2, 4 OR 6

Anchor bolt dia 'D' = 24 mm

Anchor bolt type = A A OR H

0 mm

Anchor bolt c/c along web 'f' = 180 mm min. 4D Anchor bolt c/c across web 'cc' = 180 mm min. 4D Stiffener Provided YES/NO = YES

Stiffener Spacing a ~ f = 175 mm

12 mm

Concrete Pier Dimensions

500 mm 500 mm 2300 mm Column Flange Width 'b_f' =

Column Flange Thickness 't_f' = Column Web Thickness 't_w' =

Base Plate Thickness 'T_prov' = Number of Anchor Bolt N_AB =

Anchor plate width 'W_p' = "for Type H only"

Stiffener Thickness t_stiff =

Concrete Pier Length 'L_p' = Concrete Pier Width 'B_p' = Concrete Pier Depth 'D_p' =

> 1.75D, hence OK > 1.75D, hence OK Minimum of (f - tstiff)/2 - w, (cc - tw)/2 - w > 1.75D, hence OK > 4do, hence OK > 4do, hence OK

+ive value implies compression & -ive implies tension.

(for partial area of concrete support s/t √A2/A1 < 2)

mm

For the yielding limit state, the required minimum thickness of the base plate can be calculated as follows (AISC,2005d) = 0.65 as per Section 9.3 of ACI318-08.

The base plate in bending is reinforced by means of stiffener plates providing fixed edge conditions on 3 sides.

However conservatively analyzing the base plate with Roark's formulae applicable to simply-supported plate s/t concentrared load.

BASE PLATE SIZING

Material Specifications

Base Plate Steel 248 MPa

Base Plate Steel 400 MPa

Plinth Concrete 28 MPa

Base plate bearing interface cantilever m = (N - 0.95d)/2

= 35.2 mm

n =

= 60.8 mm

Yield line theory cantilever n' =

Note : Conservatively calculated assuming = 92.6 mm no stiffner plate.

Check for Interference

F_y = F_u = f_c' =

(B - 0.8b_f)/2 √d.b_f / 4 Assumed Base Plate Bending Plane

without stiffener plates.

m 0.95d m N 2 x f = F d f f bf cc B 0 .8 bf n n

= 115 mm (B - cc)/2 = 115 mm Minimum of (f - tstiff)/2 - w, (cc - tw)/2 - w = 76.5 mm 305 mm (Bp - cc)/2 = 305 mm

Base Plate Edge Distance along Length e_L = (N - f x (N_AB/2 - 1))/2 Base Plate Edge Distance along Length e_B =

Wrench Clearance from c/L of A.B. e_WR=

Anchor Bolt Edge Distance along Length e_ABL = (L_p - f x (N_AB/2 - 1))/2 Anchor Bolt Edge Distance along Width e_ABB =

BASE PLATE DESIGN

Base Plate Design Forces from Column Support Reactions

For the critical load comb. L/C 245 forces @ column support are;

Axial Load 'Pu' = -413.4 KN +ive value implies compression & -ive implies tension.

Check for Concrete Bearing

Design Bearing Strength =

= (for partial area of concrete support s/t √A2/A1 < 2)

where = N x B = 176400

= = 640000

5197.92 KN Check for Plate Thickness in Axial Compression

Uniform pressure over base plate q = N/A

The largest base plate cantilever 'c' = Maximum of m, n & n' = 92.6

For the yielding limit state, the required minimum thickness of the base plate can be calculated as follows (AISC,2005d) >= N/A mm where a = 173 mm b = 179 mm a/b = 0.966 0.301 N/A Check for Plate Thickness in Axial Tension

103.35 KN As per Clause #J.8 of AISC360-05,

ф_c.P_p ф_c = 0.65 as per Section 9.3 of ACI318-08. 0.65 x (0.85 x fc' x A₁ x √A₂/A₁)

A_{1 mm}2

A₂ L_p x B_{p mm}2

Therefore the concrete bearing strength ф_c.P_p =

N/mm2 For the base plate without stiffener plates

t_p(req) >= c

√

For the base plate with stiffener plates

β₁ =

Therefore the bending stress σ_max = N/mm2

The base plate in bending is reinforced by means of stiffener plates providing fixed edge conditions on 3 sides.

However conservatively analyzing the base plate with Roark's formulae applicable to simply-supported plate s/t concentrared load.

where

32.4 mm a = 173 mm b = 179 mm

ν = 0.3 (Poissons ratio for isotropic steel) Therefore a/b = 0.966 32.40 mm β = 0.435 111.06 < 0.9Fy, hence OK Radius of nut r_o = r_o' =

COLUMN BASE BOUNDARY CONDITION : PINNED DIMENSIONS Column Dimensions Column Section = W14x120 Column Depth 'd' = 368 mm 373 mm 23.9 mm 15 mm

Allround weld size 'w' = 10 mm Base Plate Dimensions

Base Plate Length 'N' = 420 mm Base Plate Width 'B' = 420 mm

30 mm

4 2, 4 OR 6

Anchor bolt dia 'D' = 36 mm

Anchor bolt type = A A OR H

0 mm

Anchor bolt c/c along web 'f' = 190 mm min. 4D Anchor bolt c/c across web 'cc' = 190 mm min. 4D Stiffener Provided YES/NO = YES

Stiffener Spacing a ~ f = 185 mm

12 mm

Concrete Pier Dimensions

800 mm 800 mm 2100 mm Column Flange Width 'b_f' =

Column Flange Thickness 't_f' = Column Web Thickness 't_w' =

Base Plate Thickness 'T_prov' = Number of Anchor Bolt N_AB =

Anchor plate width 'W_p' = "for Type H only"

Stiffener Thickness t_stiff =

Concrete Pier Length 'L_p' = Concrete Pier Width 'B_p' = Concrete Pier Depth 'D_p' =

> 1.75D, hence OK > 1.75D, hence OK Minimum of (f - tstiff)/2 - w, (cc - tw)/2 - w > 1.75D, hence OK > 4do, hence OK > 4do, hence OK

+ive value implies compression & -ive implies tension.

(for partial area of concrete support s/t √A2/A1 < 2)

mm

For the yielding limit state, the required minimum thickness of the base plate can be calculated as follows (AISC,2005d) = 0.65 as per Section 9.3 of ACI318-08.

The base plate in bending is reinforced by means of stiffener plates providing fixed edge conditions on 3 sides.

However conservatively analyzing the base plate with Roark's formulae applicable to simply-supported plate s/t concentrared load.