Vibrational Analysis of Machine Foundation Page 1 of 9

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 = 20.00 %

Global Reference Point

Global Reference Point X = 0.00 mm

Global Reference Point Y = 0.00 mm

Global Reference Point Z = 0.00 mm

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Machine Block Geometry

Block Length = 3000.00 mm

Block Width = 1200.00 mm

Block Thickness = 600.00 mm

Pier Geometry

Pier Length = 2700.00 mm

Pier Width = 900.00 mm

Pier Thickness = 300.00 mm

Pier Location

X1 = 150.00 mm

Z1 = 150.00 mm

Machine Loading

Dynamic Machine Weight = 3924.00 N

Static Machine Weight = 21880.00 N

Primary Speed = 1780.00 rpm

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X Load Location = 1650.00 mm

Y Load Location = 780.00 mm

Z Load Location = 756.00 mm

Number of Mode Shapes = 10

Loading Type = Unbalanced Mass

Eccentricity of Unbalanced Mass = 0.00 mm

Soil Parameters

Soil Spring Generation Method = Richard Whitman Method

Consider Embedment Independence = Effect Considered

Soil Embedment = 600.00 mm

Back Fill Shear = 10.00 ksi

Soil Type = Cohesive

Consider Damping = Effect Considered

Concrete Damping Percentage = 0.00

Wet Soil Density (ρwet) = 120.00 lb/ft3

Shear Modulus (G) = 10.00 ksi

Poisson's Ratio (μ) = 0.45 ksi

Soil Springs

Equivalent Radius Calculation

ACI 351.3R-31

Translation Equivalent Radius : = 3.51ft ...(4-9a)

Dimensionless Freqency : = 1.05 ...(4-11)

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Richart Whitman Method

Vertical Spring = = 36783.17 kips/ft ...(4-13a)

Horizontal Spring = = 26180.96 kips/ft ...(4-13b)

Horizontal Spring = = 26180.96 kips/ft ...(4-13b)

Vertical Mass Ratio = = 0.56 ...(4-12a)

Horizontal Mass Ratio = = 0.78 ...(4-12b)

Vertical Damping Ratio = = 0.57 ...(4-12a)

Horizontal Damping Ratio = = 0.33 ...(4-12b)

Soil Spring Adjustment Based on Material Damping and Soil Embedmentment

Adjusted Spring = = 36783.17 kips/ft ...(4-23)

Adjusted Damping Constant = = 304.76 kips/ft ...(4-23)

Adjusted Damping Constant = = 270.64 kips/ft ...(4-23)

(Equations for soil embedment correction are not shown.)

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Unbalanced Dynamic Load Calculation

Machine Frequency ωo = 186.66

Service Factor Sf = 2.00 ...3.2.2.1b

Force = = 0.01 kip ...(3-3)

Moment Mx = 0.01 kip-ft

Calculated Modal Frequencies and Mass Participation

Number of Modes Shapes: 10

Frequency Period Participation Participation Participation Accumulated Accumulated Accumulated

Mode
(Hz) (sec) X (%) Y (%) Z (%) X (%) Y (%) Z (%)
1 17.31 0.06 0.00 0.66 71.87 0.00 0.66 71.87
2 27.65 0.04 70.05 2.10 0.05 70.05 2.76 71.93
3 31.55 0.03 2.94 77.18 1.41 72.99 79.94 73.33
4 44.97 0.02 0.07 0.00 0.07 73.06 79.94 73.40
5 54.23 0.02 19.31 7.67 0.43 92.37 87.61 73.83
6 56.99 0.02 6.99 12.11 1.80 99.36 99.72 75.63
7 67.63 0.01 0.01 0.28 24.27 99.37 100.00 99.91
8 96.35 0.01 0.62 0.00 0.00 100.00 100.00 99.91
9 106.99 0.01 0.00 0.00 0.09 100.00 100.00 100.00
10 0.00 1000000.00 0.00 0.00 0.00 100.00 100.00 100.00

Dynamic Displacement Summary

Node Displacement X (in) Displacement Y (in) Displacement Z (in)

2497 0.013136 -0.000733 -0.000099
1030 0.000170 0.018482 0.025499
2497 -0.000098 -0.004804 0.036337
2009 -0.000279 -0.018361 0.006292
923 -0.000193 -0.018493 0.025462
2524 0.010133 -0.007550 -0.000517

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Mode Foundation Frequency Machine Frequency

Frequency Check
No (Hz) (Hz)

1 17.31 29.67 Machine Frequency OK

Machine Frequency is within 20.00 % of Foundation

2 27.65 29.67
Frequency

Machine Frequency is within 20.00 % of Foundation

3 31.55 29.67
Frequency

4 44.97 29.67 Machine Frequency OK

5 54.23 29.67 Machine Frequency OK

6 56.99 29.67 Machine Frequency OK

7 67.63 29.67 Machine Frequency OK

8 96.35 29.67 Machine Frequency OK

9 106.99 29.67 Machine Frequency OK

10 0.00 29.67 Machine Frequency OK

Transverse Amplitude Check

Maximum Transverse Amplitude : 0.000005ft

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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

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Severity Chart ACI 351.3R-04 Fig 3.10

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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

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