Vibrational Analysis of Machine Foundation
Page 1 of 8
Vibrational Analysis of Machine Foundation
ACI 351.3R-04 (FEA Method)
Input Data
Machine Data
Foundation Type
=
Single Block
Machine Type
=
Rotating Machine
Resonance Limit
=
50.00
%
Global Reference Point
Global Reference Point X
=
0.00
in
Global Reference Point Y
=
0.00
in
Global Reference Point Z
=
0.00
in
file://N:\Fan Boiler North\Boiler Fan\Reports\CalculationSheet.xml
22/03/2018
Vibrational Analysis of Machine Foundation
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Machine Block Geometry
Block Length
=
246.00
in
Block Width
=
102.00
in
Block Thickness
=
12.00
in
Pier Geometry
Pier Length
=
222.00
in
Pier Width
=
78.00
in
Pier Thickness
=
83.56
in
Pier Location
X1
=
12.00
in
Z1
=
12.00
in
Machine Loading
Dynamic Machine Weight
=
1976.00
lbf
Static Machine Weight
=
24908.00
lbf
Primary Speed
=
1780.00 rpm
file://N:\Fan Boiler North\Boiler Fan\Reports\CalculationSheet.xml
22/03/2018
Vibrational Analysis of Machine Foundation
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X Load Location
=
111.50
in
Y Load Location
=
143.06
in
Z Load Location
=
54.00
in
Number of Mode Shapes
=
50
Loading Type
=
Direct Loading
Soil Parameters
Soil Spring Generation Method
=
Richard Whitman Method
Consider Embedment Independence
=
Effect Considered
Soil Embedment
=
4.50
ft
Back Fill Shear
=
10.00
ksi
Soil Type
=
Cohesive
Consider Damping
=
Effect Considered
Concrete Damping Percentage
=
0.00
Wet Soil Density (ρwet)
=
100.00
Shear Modulus (G)
=
10.00
ksi
Poisson's Ratio (µ)
=
0.30
ksi
lb/ft3
Soil Springs
Equivalent Radius Calculation
ACI 351.3R-31
Translation Equivalent Radius : R=abπ = 89.37in ...(4-9a)
Dimensionless Freqency : a0=R×ωm×ρG = 2.04 ...(4-11)
file://N:\Fan Boiler North\Boiler Fan\Reports\CalculationSheet.xml
22/03/2018
Vibrational Analysis of Machine Foundation
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Richart Whitman Method
Vertical Spring
=
Dv=0.425Bv
=
61286.37
kips/ft ...(4-13a)
Horizontal Spring
=
ku=32×1-ν32×78ν×G×R
=
52226.64
kips/ft ...(4-13b)
Horizontal Spring
=
ku=32×1-ν32×78ν×G×R
=
52226.64
kips/ft ...(4-13b)
Vertical Mass Ratio
=
Bv=1-ν4×mρ×R3
=
0.76
...(4-12a)
Horizontal Mass Ratio
=
Bu=1-8×ν32×1ν×mρ×R3
=
0.89
...(4-12b)
Vertical Damping Ratio
=
Dv=0.425Bv
=
0.49
...(4-12a)
Horizontal Damping Ratio
=
ku=32×1-ν32×78ν×G×R
=
0.31
...(4-12b)
Soil Spring Adjustment Based on Material Damping and Soil Embedmentment
Adjusted Spring
=
kvadj=kv-2×βm×cv×ωm
=
0.00
kips/ft ...(4-23)
Adjusted Damping Constant
=
cvadj=cv+2×βm×kvωm
=
0.00
kips/ft ...(4-23)
Adjusted Damping Constant
=
cvadj=cv+2×βm×kvωm
=
0.00
kips/ft ...(4-23)
(Equations for soil embedment correction are not shown.)
Calculated Modal Frequencies and Mass Participation
Number of Modes Shapes: 11
Frequency
(Hz)
Period
(sec)
1
6.94
0.14
0.00
0.01
74.14
0.00
0.01
74.14
2
11.30
0.09
74.19
0.10
0.00
74.19
0.11
74.14
3
15.62
0.06
0.26
91.80
0.02
74.45
91.91
74.16
4
18.25
0.05
0.00
0.00
0.03
74.45
91.91
74.19
5
23.38
0.04
24.80
0.78
0.00
99.25
92.69
74.19
Mode
Participation Participation Participation Accumulated Accumulated Accumulated
X (%)
Y (%)
Z (%)
X (%)
Y (%)
Z (%)
file://N:\Fan Boiler North\Boiler Fan\Reports\CalculationSheet.xml
22/03/2018
Vibrational Analysis of Machine Foundation
Page 5 of 8
Frequency
(Hz)
Period
(sec)
6
26.19
0.04
0.71
7.21
0.68
99.95
99.89
74.88
7
27.88
0.04
0.01
0.11
25.06
99.96
100.00
99.94
8
53.61
0.02
0.04
0.00
0.00
100.00
100.00
99.94
9
56.46
0.02
0.00
0.00
0.06
100.00
100.00
100.00
10
0.00
1000000.00
0.00
0.00
0.00
100.00
100.00
100.00
11
0.00
1000000.00
0.00
0.00
0.00
100.00
100.00
100.00
Mode
Participation Participation Participation Accumulated Accumulated Accumulated
X (%)
Y (%)
Z (%)
X (%)
Y (%)
Z (%)
Dynamic Displacement Summary
Node Displacement X (in) Displacement Y (in) Displacement Z (in)
3264
0.080911
0.004197
0.000034
2525
-0.000677
0.106802
0.066178
3264
0.000033
-0.006324
0.247406
515
-0.001354
0.105573
0.039364
3065
0.000520
-0.106839
0.066596
515
0.040773
-0.044858
-0.000599
Mode
No
Foundation Frequency
(Hz)
Machine Frequency
(Hz)
Frequency Check
1
6.94
29.67
Machine Frequency OK
2
11.30
29.67
Machine Frequency OK
3
15.62
29.67
Machine Frequency is within 50.00 % of Foundation
Frequency
4
18.25
29.67
Machine Frequency is within 50.00 % of Foundation
Frequency
5
23.38
29.67
Machine Frequency is within 50.00 % of Foundation
Frequency
6
26.19
29.67
Machine Frequency is within 50.00 % of Foundation
Frequency
7
27.88
29.67
Machine Frequency is within 50.00 % of Foundation
Frequency
8
53.61
29.67
Machine Frequency OK
9
56.46
29.67
Machine Frequency OK
10
0.00
29.67
Machine Frequency OK
11
0.00
29.67
Machine Frequency OK
file://N:\Fan Boiler North\Boiler Fan\Reports\CalculationSheet.xml
22/03/2018
Vibrational Analysis of Machine Foundation
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Transverse Amplitude Check
Maximum Transverse Amplitude : 0.000000in
Vibration Criteria for Rotating Machine ACI 351.3R-04 Fig 3.9
A: No Faults. Foundation is safe for machine vibrations
B: Minor Faults. Foundation needs review
C: Faulty. Foundation should be resized
D: Failure is near. Foundation is unsafe for machine vibrations
E: Dangerous. Foundation is unsafe for machine vibrations
Maximum Transverse Amplitude is less than graph range specified by ACI 351.3R-04 Fig 3.9
file://N:\Fan Boiler North\Boiler Fan\Reports\CalculationSheet.xml
22/03/2018
Vibrational Analysis of Machine Foundation
Page 7 of 8
Severity Chart ACI 351.3R-04 Fig 3.10
Maximum Transverse Amplitude is less than graph range specified by ACI 351.3R-04 Fig 3.10
file://N:\Fan Boiler North\Boiler Fan\Reports\CalculationSheet.xml
22/03/2018
Vibrational Analysis of Machine Foundation
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Permissible Displacement ACI 351.3R-04 Fig 3.11
Maximum Transverse Amplitude is less than graph range specified by ACI 351.3R-04 Fig 3.11
Print Calculation Sheet
file://N:\Fan Boiler North\Boiler Fan\Reports\CalculationSheet.xml
22/03/2018