Base Plate Thickness
Short Description
Method to calculate base plate thickness for pinned base plate. It covers...
Description
KNPC MINA ABDULLAH REFINERY CLEAN FUELS P BASE PLATE DESIGN
BASE PLATE SIZING N d
0.8bf n
cc
bf
B
n
2xf=F f f
m
0.95d
m
Assumed Base Plate Bending Plane without stiffener plates.
Material Specifications Base Plate Steel
Fy =
248
MPa
Base Plate Steel
Fu =
400
MPa
Plinth Concrete
fc' =
28
MPa
Base plate bearing interface cantilever
m n
Yield line theory cantilever Note : Conservatively calculated assuming no stiffner plate. Check for Interference
n'
= (N - 0.95d)/2 = 32.3 = (B - 0.8bf)/2 = 48.4 √d.b / 4 = f = 74.9
mm mm mm
KNPC MINA ABDULLAH REFINERY CLEAN FUELS P BASE PLATE DESIGN
Base Plate Edge Distance along Length eL = (N - f x (NAB/2 - 1))/2 = 110 Base Plate Edge Distance along Length eB = (B - cc)/2
mm
= 60 mm Wrench Clearance from c/L of A.B. eWR= Minimum of (f - tstiff)/2 - w, (cc - tw)/2 - w Anchor Bolt Edge Distance along Length eABL
= 73.5 mm = (Lp - f x (NAB/2 - 1))/2 160
Anchor Bolt Edge Distance along Width eABB
mm
= (Bp - cc)/2 =
160
mm
KNPC MINA ABDULLAH REFINERY CLEAN FUELS P BASE PLATE DESIGN
BASE PLATE DESIGN Base Plate Design Forces from Column Support Reactions 213 forces @ column support are; For the critical load comb. L/C Axial Load 'Pu' = -187.1 KN +ive value implies compression & -ive Check for Concrete Bearing As per Clause #J.8 of AISC360-05, Design Bearing Strength
фc.Pp
=
фc = 0.65 as per Section 9.3 of ACI318-08.
= 0.65 x (0.85 x fc' x A1 x √A2/A1) A1
where
=
NxB Lp x Bp
A2
= Therefore the concrete bearing strength фc.Pp =
(for partial area of concre
=
120000 mm2
=
250000 mm2 2679.48
KN
Check for Plate Thickness in Axial Compression
Uniform pressure over base plate q = N/A N/mm2 For the base plate without stiffener plates 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 tp(req) >= c √2Pu/(фbFyBN) Фb = resistance factor for bending in LRFD, 0.9 >=
N/A
mm
For the base plate with stiffener plates
where
a= b= a/b = β1 =
163 122.25 1.333
mm mm
0.591 Therefore the bending stress σmax = Check for Plate Thickness in Axial Tension Tension per bolt WAB =
N/A
46.775
KN
N/mm2
KNPC MINA ABDULLAH REFINERY CLEAN FUELS P BASE PLATE DESIGN
The base plate in bending is reinforced by means of stiffener plates providing fixed edge conditions on 3 However conservatively analyzing the base plate with Roark's formulae applicable to simply-supported p
where Radius of nut
Therefore
ro = a b ν a/b ro'
= = = = =
21.6 163 122.25 0.3 1.333
mm mm mm (Poissons ratio for isotropic steel)
21.60 mm β = 0.74 Therefore the bending stress σmax =
85.99
N/mm2
< 0.9Fy, hence OK
CLEAN FUELS PROJECT ESIGN
PINNED
COLUMN BASE BOUNDARY CONDITION :
DIMENSIONS Column Dimensions Column Section Column Depth 'd' Column Flange Width 'bf'
= = =
W14x61 353
mm
254
mm
Column Flange Thickness 'tf'
=
16.4
mm
Column Web Thickness 'tw'
=
mm mm
Allround weld size 'w'
=
9.5 8
Base Plate Dimensions Base Plate Length 'N' Base Plate Width 'B' Base Plate Thickness 'Tprov'
= =
400 300
mm mm
=
25
mm
Number of Anchor Bolt NAB
=
4 24 A
mm
0
mm
180 180 YES 175
mm mm
12
mm
Concrete Pier Dimensions Concrete Pier Length 'Lp' =
500
mm
Concrete Pier Width 'Bp'
=
500
mm
Concrete Pier Depth 'Dp'
=
2300
mm
Anchor bolt dia 'D' = Anchor bolt type = Anchor plate width 'Wp' = "for Type H only" Anchor bolt c/c along web 'f' = Anchor bolt c/c across web 'cc' = Stiffener Provided YES/NO = Stiffener Spacing a ~ f = Stiffener Thickness tstiff =
2, 4 OR 6
A OR H
mm
min. 4D min. 4D
CLEAN FUELS PROJECT ESIGN
> 1.75D, hence OK > 1.75D, hence OK - w, (cc - tw)/2 - w > 1.75D, hence OK > 4do, hence OK > 4do, hence OK
CLEAN FUELS PROJECT ESIGN
ompression & -ive implies tension.
318-08.
artial area of concrete support s/t √A2/A1 < 2)
mm alculated as follows (AISC,2005d)
CLEAN FUELS PROJECT ESIGN
ge conditions on 3 sides. imply-supported plate s/t concentrared load.
Fy, hence OK
Reference : AISC Steel Design Guide 1
KNPC MINA ABDULLAH REFINERY CLEAN FUEL BASE PLATE DESIGN
BASE PLATE SIZING
N d
0.8bf n
cc
bf
B
n
2xf=F f f
m
0.95d
m
Assumed Base Plate Bending Plane without stiffener plates.
Material Specifications Base Plate Steel
Fy =
248
MPa
Base Plate Steel
Fu =
400
MPa
Plinth Concrete
fc' =
28
MPa
Base plate bearing interface cantilever
m n
=
(N - 0.95d)/2 = 35.2 = (B - 0.8bf)/2 =
Yield line theory cantilever Note : Conservatively calculated assuming no stiffner plate. Check for Interference
n'
60.8 √d.b / 4 = f = 92.6
mm mm mm
KNPC MINA ABDULLAH REFINERY CLEAN FUEL BASE PLATE DESIGN
Base Plate Edge Distance along Length eL = (N - f x (NAB/2 - 1))/2 = 115 Base Plate Edge Distance along Length eB = (B - cc)/2
mm
= 115 mm Wrench Clearance from c/L of A.B. eWR= Minimum of (f - tstiff)/2 - w, (cc - tw)/2 Anchor Bolt Edge Distance along Length eABL
= 76.5 mm = (Lp - f x (NAB/2 - 1))/2 305
Anchor Bolt Edge Distance along Width eABB
mm
= (Bp - cc)/2 =
305
mm
KNPC MINA ABDULLAH REFINERY CLEAN FUEL BASE PLATE DESIGN
BASE PLATE DESIGN Base Plate Design Forces from Column Support Reactions 245 forces @ column support are; For the critical load comb. L/C Axial Load 'Pu' = -413.4 KN +ive value implies compression & Check for Concrete Bearing As per Clause #J.8 of AISC360-05, Design Bearing Strength
фc.Pp
=
фc = 0.65 as per Section 9.3 of ACI318-08.
= 0.65 x (0.85 x fc' x A1 x √A2/A1) A1
where
=
NxB Lp x Bp
A2
= Therefore the concrete bearing strength фc.Pp =
(for partial area of co
=
176400 mm2
=
640000 mm2 5197.92
KN
Check for Plate Thickness in Axial Compression
N/mm2 Uniform pressure over base plate q = N/A For the base plate without stiffener plates 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 follow tp(req)
>= c √2Pu/(фbFyBN) >=
N/A
Фb = resistance factor for bending in LRFD, 0.9
mm
For the base plate with stiffener plates
where
a= b= a/b = β1 =
173 179 0.966
mm mm
0.301 Therefore the bending stress σmax = Check for Plate Thickness in Axial Tension Tension per bolt WAB =
N/A
103.35
KN
N/mm2
KNPC MINA ABDULLAH REFINERY CLEAN FUEL BASE PLATE DESIGN
The base plate in bending is reinforced by means of stiffener plates providing fixed edge conditions on 3 However conservatively analyzing the base plate with Roark's formulae applicable to simply-supported p
where Radius of nut
Therefore
ro = a b ν a/b ro'
= = = = =
32.4 173 179 0.3 0.966
mm mm mm (Poissons ratio for isotropic steel)
32.40 mm β = 0.435 Therefore the bending stress σmax =
111.06
N/mm2
< 0.9Fy, hence OK
CLEAN FUELS PROJECT SIGN
PINNED
COLUMN BASE BOUNDARY CONDITION :
DIMENSIONS Column Dimensions Column Section Column Depth 'd' Column Flange Width 'bf'
= = =
W14x120 368
mm
373
mm
Column Flange Thickness 'tf'
=
23.9
mm
Column Web Thickness 'tw'
=
Allround weld size 'w'
=
15 10
mm mm
Base Plate Dimensions Base Plate Length 'N' Base Plate Width 'B' Base Plate Thickness 'Tprov'
= = =
420 420
mm mm
30
mm
4 36 A
mm
0
mm
190 190 YES 185
mm mm
12
mm
Number of Anchor Bolt NAB
=
Anchor bolt dia 'D' = Anchor bolt type = Anchor plate width 'Wp' = "for Type H only" Anchor bolt c/c along web 'f' = Anchor bolt c/c across web 'cc' = Stiffener Provided YES/NO = Stiffener Spacing a ~ f = Stiffener Thickness tstiff =
2, 4 OR 6
A OR H
mm
Concrete Pier Dimensions Concrete Pier Length 'Lp'
=
800
mm
Concrete Pier Width 'Bp'
=
800
mm
Concrete Pier Depth 'Dp'
=
2100
mm
min. 4D min. 4D
CLEAN FUELS PROJECT SIGN
> 1.75D, hence OK > 1.75D, hence OK
- w, (cc - tw)/2 - w > 1.75D, hence OK > 4do, hence OK > 4do, hence OK
CLEAN FUELS PROJECT SIGN
mpression & -ive implies tension.
ACI318-08.
rtial area of concrete support s/t √A2/A1 < 2)
mm ated as follows (AISC,2005d)
CLEAN FUELS PROJECT SIGN
onditions on 3 sides. ly-supported plate s/t concentrared load.
y, hence OK
Reference : AISC Steel Design Guide 1
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