Ambient Vibration

8/2/2019 Ambient Vibration

http://slidepdf.com/reader/full/ambient-vibration 1/18

MEMORANDUM #9

Date: 16 November 2009

Subject: Central Corridor Light Rail Project – WIA Ambient VibrationMeasurement Data

This memorandum presents a summary of the results of the ambient vibration measurementsconducted in laboratory spaces at the University of Minnesota (UM) by Wilson, Ihrig & Associates(WIA) during two site visits to the campus. The first set of measurements was conducted 20 through23 January 2009, and the second set 9 through l4 September 2009.

Measurement MethodologyLong-term ambient, floor vibration data were obtained by WIA in a total of nineteen (19) UMlaboratories. The laboratories for which long-term data were obtained are listed in Table 1.

Table 1: Laboratory Spaces for which WIA Obtained Long-term Ambient VibrationNumber Building Laboratory Space Lab Manager

1 467 Kass2 194/196 Yao3

Koltoff Hall93A/94 Blank

4 1-130 (NMR lab) Ostrowski5 2-231/2-236 Nick 6

Nils Hasselmo Hall7-231 Netoff

7 323 Giles8 54 Leighton9

AmundsonB22 Frisbie

10 2-270/2-274 Salapaka

11

Electrical Engineering Computer Science

1-170 Cibuzar12 Molecular and Cellular Biology 1-128B Gammill13 3-142 Barnett14

Jackson Hall1-155 N/A

15 Moos Tower 5-108A Hays16 8-139B Johnson17 3-119 --18

Weaver Densford Hall3-140 --

19 717 Delaware (NMR lab) Ostrowski



WILSON, IHRIG & ASSOCIATES, INC. 2 CCLRTAmbient Vibration in UM Laboratories

During the January 2009 site visit, WIA obtained long-term vibration data for eleven (11)laboratories. WIA also conducted short-term vibration measurements at selected sites during thisfirst visit. The short-term vibration data were obtained by making tape recordings of short samplesof ambient vibration and were intended to be supplemental to the long-term measurements.

During the September 2009 site visit, WIA obtained long-term data for ten (10) labs, which includedrepeating measurements in Nils Hasselmo Hall (NMR lab in NHH 1-130) and Weaver Densford Hall(in 8-139B). No short-term recordings were made in the second round of measurements. Thelocations and times of all the long-term and short-term measurements are summarized in Table 2.

Table 2: Summary of WIA Ambient Vibration Measurement Details*

Long-Term MeasurementsLocation

Start Finish ApproximateDuration

AdditionalShort-Term

Measurements

Kolthoff Hall Room 467 9:20 AM(1/20/09) 9:20 AM(1/21/09) 24 hours 2-3 PM, 10 PM(1/20/09)

Kolthoff Hall Labs 194/196 9:50 AM(1/20/09)

9:40 AM(1/21/09) 24 hours 3-4 PM, 9:30 PM

(1/20/09)

Kolthoff Hall 93A/94(basement)

10:20 AM(1/20/09)

10:00 AM(1/21/09) 24 hours 4-5 PM, 9 PM

(1/20/09)

Smith S20 (basement) N/A N/A N/A 5 PM, 8:30 PM(1/20/09)

Nils Hasselmo HallNMR Lab 1-130 (storageroom)

10:30 AM(1/21/09)

10:00 AM(1/22/09) 24 hours 3:40 PM, 10 PM

(1/21/09)

Nils Hasselmo HallRooms 2-231/2-236

11:25 AM(1/21/09)

10:20 AM(1/22/09) 23 hours

4:30 PM(1/21/09)

Amundson Hall Room 323 11:00 AM(1/21/09)

10:45 AM(1/22/09) 24 hours 1:50-2:50 PM, 10:45 PM

(1/21/09)

Nils Hasselmo Hall Room 7-231A

12:00 PM(1/21/09)

10:40 AM(1/22/09) 23 hours 2:50-3:30 PM

(1/21/09)

Electrical Eng. & ComputerScience Rooms 2-270/2-274

11:10 AM(1/22/09)

12:00 PM(1/23/09) 25 hours 3-4 PM

(1/22/09)

Electrical Eng. & ComputerScience Room 1-170

11:30 AM(1/22/09)

11:00 AM(1/23/09) 24 hours 9:45 PM

(1/22/09)

Weaver Densford HallRoom 8-139B

12:10 PM(1/22/09)

10:50 AM(1/23/09) 23 hours 5 PM, 10:45 PM

(1/22/09)

Molecular and CellularBiology Room 1-128B

1:00 PM(1/22/09)

1:45 AM(1/23/09) 13 hours 4-5 PM, 9:15 PM

(1/22/09)

Philip Wangensteen BuildingRoom 7-218 N/A N/A N/A 10:15 AM (1/23/09)

Amundson Hall Room 54 12:50 PM(9/9/09)

9:16 AM(9/10/09) 20 hours N/A

Amundson Hall Room B22(basement)

2:28 PM(9/9/09)

11:17 AM(9/10/09) 20 hours N/A




Long-Term MeasurementsLocation

Start Finish ApproximateDuration

AdditionalShort-Term

Measurements

Jackson Hall Room 3-142 3:15 PM

(9/9/09)

11:54 AM

(9/10/09)21 hours 11:30 AM (1/23/09)

Jackson Hall Room 1-155(basement)

3:52 PM(9/9/09)

2:50 PM(9/10/09) 23 hours N/A

Moos Tower Room 5-108A 11:05 AM(9/10/09)

10:12 AM(9/14/09) 3 days 23 hours N/A

717 Delaware (NMR) 11:43 AM(9/10/09)

9:56 AM(9/11/09) 22 hours N/A

Weaver Densford HallRoom 8-139B

3:42 PM(9/10/09)

3:37 PM(9/11/09) 24 hours N/A

Nils Hasselmo HallNMR Lab 1-130 (isolated slab)

10:48 AM(9/11/09)

10:51 AM(9/14/09) 3 days N/A

Weaver Densford HallRoom 3-119

4:21 PM(9/11/09)

9:43 AM(9/14/09) 2 days 17 hours N/A


3:59 PM(9/11/09)

9:57 AM(9/14/09) 2 days 18 hours N/A

* Measurements are listed in the chronological order in which they were conducted.

The long-term vibration measurement instrumentation for each location consisted of an Endevcoseries 7700 accelerometer (either 7703A, 7705 or 7707) with a nominal sensitivity of 1,000 pC/g, aWIA low-noise charge amplifier and a Norsonic Nor140 spectral analyzer/logger. At each location,the accelerometer was attached directly to the floor surface with wax and used to measure vibrationof the floor in the vertical direction.

The Nor140 loggers were programmed to continuously log “root-mean-square” (RMS) accelerationlevels at 1-second intervals and were deployed to be left either overnight or in a few instances forseveral days to record vibration. The long-term measurement periods lasted typically between 20and 24 hours. The vibration logging ranged from 13 hours to 3 days and 23 hours, depending on theschedule of the measurements.

Instrumentation was calibrated either before and/or after each measurement using a PCB model394C06 Handheld Shaker. A photo a typical long-term measurement instrumentation configurationis shown in Figure 1. Short-term ambient vibration recordings were obtained using an accelerometer,WIA charge amplifier and a DAT recorder. Short-term recordings were taken at floor locations in

proximity to the long-term locations. The short-term measurements were supplementary to the long-term measurements.

Data Analysis and ResultsThe Nor140 analyzer output files (containing the logged acceleration data) were transferred tocomputer files. Using a proprietary, sound and vibration analysis program developed by WIA, theacceleration vibration levels in each 1/3 octave band were converted to vibration velocity levels.




Figure 1: Typical Long-term Vibration Measurement Configuration

To accomplish the conversion of acceleration to velocity the following formula was used:

Lv (dB re 10 -6 in/sec) = L a (dB re 10 -6 g) – 20 log10 (f) – 36

where f (Hz) is the 1/3 octave band center frequency.

For each set of long-term vibration velocity data (i.e., 1 second intervals of RMS data) for alaboratory, the data for that measurement location were energy averaged to obtain energy equivalentvibration levels (L eq) for the measurement period.

WIA conducted short-term measurements and tape recordings (approximately 10 to 15 minuteseach) during the course of some of the long-term measurements. The short-term measurementaccelerometers were located close to the long-term accelerometers. During the placement andremoval of the short-term accelerometer, the long-term data would not be representative of thetypical ambient environment in the laboratory. For ease of data analysis the long-term data duringthe entire period the short-term measurements were in progress were excluded from the long-termLeq average. Otherwise all logged data were averaged over the entire measurement period indicated

in Table 2 with one exception as noted. For each laboratory, the long-term ambient, floor vibrationvelocity L eq spectral values (from 4 Hz and 200 Hz) are contained in Table 3. Spectral plots of theseambient L eq vibration data are contained in the Appendix.

Long-term measurements were repeated in NHH NMR lab and Weaver Densford Hall (8-139B).The NHH NMR lab measurements were conducted in two different locations and both sets of dataare presented. The Weaver Densford 8-139B measurements were conducted in the same locationand the data are very similar. The September 2009 data are presented for Weaver Densford 8-139B.



WILSON, IHRIG & ASSOCIATES, INC. 5 Ambi

Table 3: Long-term Ambient 1/3 Octave Band L eq Floor Vibration Velocity Levels (VdB re 10 -6in/sec)

1/3 Octave Band Center Frequency -- Hz

Location4 5 6.3 8 10 12.5 16 20 25 31.5 40 50 63 80

Kolthoff Hall Room 467 30 27 29 39 50 51 49 47 37 43 42 44 47 29

Kolthoff Hall Labs194/196

19 23 25 32 37 43 44 40 39 46 41 38 45 27

Kolthoff Hall 93A/94(basement)

17 22 23 30 33 33 33 34 38 42 44 43 51 31

Nils Hasselmo HallNMR Lab 1-130(storage room) – Jan 09

16 21 22 26 32 29 33 36 33 32 29 37 40 30

Nils Hasselmo HallNMR Lab 1-130(isolated slab) – Sept 09

17 19 21 25 31 27 31 36 33 33 31 35 35 22

Nils Hasselmo HallRooms 2-231/2-236

23 25 30 33 36 43 40 46 44 48 40 37 41 30

Amundson Hall Room323

28 29 29 35 48 51 55 52 45 45 47 41 46 43

Nils Hasselmo Hall Room7-231A

35 35 41 42 43 44 43 45 47 52 48 46 53 35

Electrical Eng. &Computer Science Rooms2-270/2-274

37 33 33 33 40 46 38 39 37 36 33 38 47 28

Electrical Eng. &Computer Science Room1-170

16 20 20 19 21 22 21 19 16 18 22 14 21 9

Weaver Densford HallRoom 8-139B – Sept 09

51 52 52 51 51 49 49 49 45 47 37 41 46 32




Notes:1. Kolthoff Hall Room 467 ambient Leq from 1/20/09 9:25 AM to 1/21/09 9: 15 AM (excluding data between 2-3 PM and at 10 PM2. Kolthoff Hall Labs 194/196 ambient Leq from 1/20/09 9:50 AM to 1/21/09 9:40 AM (excluding data between 3-4 PM and 9:30-13. Kolthoff Hall 93A/94 ambient Leq from 1/20/09 10:20 AM to 1/20/09 9:50 AM (excluding data between 4-5 PM and 9-9:30 PM d

4. Nils Hasselmo Hall NMR Lab 1-130 (storage room) ambient Leq from 1/21/09 10:40 AM to 1/22/09 9:50 AM (excluding dataPM due to WIA activity)5. Nils Hasselmo Hall NMR Lab 1-130 (isolated slab) ambient Leq from 9/11/09 11 AM to 9/12/09 11 AM6. Nils Hasselmo Hall Rooms 2-231/2-236 ambient Leq from 1/21/09 11:30 AM to 1/22/09 10:10 AM (excluding data at 4:30 PM 7. Amundson Hall Room 323 ambient Leq from 1/21/09 11:00 AM to 1/22/09 10:30 AM (excluding data between 1:50-2:50 PM and

activity)8. Nils Hasselmo Hall Room 7-231A ambient Leq from 1/21/09 12:30 PM to 1/22/09 10:30 AM (excluding data between 2:50-3:3

excluding data between 7 PM-1:15AM because increased levels do not appear to be typical for this room)

Molecular and CellularBiology Room 1-128B

23 22 22 22 24 23 22 21 23 27 24 29 40 24

Amundson Hall Room 54 33 29 29 42 43 45 44 40 42 46 33 40 48 33

Amundson Hall RoomB22

21 21 20 26 38 37 34 34 40 36 30 33 39 31

Jackson Hall Room 3-142 26 32 41 48 47 56 58 56 51 50 45 34 38 39

Moos Tower Room 5-108A

43 54 55 51 47 49 43 44 44 41 37 38 41 35

717 Delaware (NMR) 27 27 31 40 46 48 49 48 46 45 33 32 33 31

Weaver Densford HallRoom 3-119 40 50 47 48 46 43 40 32 34 36 33 28 29 26


34 43 50 43 49 45 45 40 43 41 32 35 41 29

Jackson Hall Room 1-155 17 18 19 25 29 29 29 31 30 29 22 26 32 23




9. Electrical Eng. & Computer Science Rooms 2-270/2-274 ambient Leq from 1/22/09 11:12 AM to 1/23/09 11:58 AM (excludin10. Electrical Eng. & Computer Science Room 1-170 ambient Leq from 1/22/09 11:40 AM to 1/23/09 10:50 AM11. Weaver Densford Hall Room 8-139B ambient Leq from 9/10/09 3:45 PM to 9/11/09 3:30 PM12. Molecular and Cellular Biology Room 1-128B ambient Leq from 1/22/09 1:00 PM to 1/23/09 1:45 AM (excluding 4-5 PM and 13. Amundson Hall Room 54 ambient Leq from 9/9/09 12:50 PM to 9/10/09 9:15 AM

14. Amundson Hall B22 ambient Leq from 9/9/09 2:30 PM to 9/10/09 11:15 AM15. Jackson Hall Room 3-142 ambient Leq from 9/9/09 3:15 PM to 9/10/09 11:50 AM16. Moos Tower Room 5-108A ambient is a 95-hour Leq from 9/10/09 11:13 AM to 9/14/09 10:12 AM to average out fluctua17. 717 Delaware (NMR) ambient Leq from 9/10/09 11:43 AM to 9/11/09 9:54 AM18. Weaver Densford Hall Room 3-119 is a 64-hour Leq from 9/11/09 5 PM to 9/14/09 9 AM to average out fluctuations in ind19. Weaver Densford Hall Room 3-140 is a 65-hour Leq from 9/11/09 4 PM to 9/14/09 9 AM to average out fluctuations in indi20. Jackson Hall Room 1-155 ambient Leq from 9/9/09 4:05 PM to 9/10/09 2:40 PM



WILSON, IHRIG & ASSOCIATES, INC. A-1 CCLRTAmbient Vibration in UM Laboratories

APPENDIX A

Spectral Plots of Long-term Ambient L eq Floor Vibration VelocityIn

University of Minnesota Laboratories




2 4 8 16 31.5 63 125 250 500OA AWOctave Band Center Frequency, Hz

70

60

50

40

30

20

10

0

1 / 3 O

c t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e

1 0 - 6 i n / s

Figure A-1: Kolthoff Hall Room 467 Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c

t a v e

B a n

d R M S V e

l o c

i t y L e v e

l - -

d B r e

1 0 - 6

i n / s

Figure A-2: Kolthoff Hall Labs 194/196 Ambient L eq





70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - - d B r e 1

0 - 6

i n / s

Figure A-3: Kolthoff Hall 93A/94 Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e

1 0 - 6

i n / s

Figure A-4: Nils Hasselmo Hall 1-130 (isolated slab) Ambient L eq – Sept 09





70

60

50

40

30

20

10

0

1 / 3 O c

t a v e

B a n

d R M S V e

l o c

i t y L e v e

l - - d B r e 1

0 - 6

i n / s

Figure A-5: Nils Hasselmo Hall 2-231/2-236 Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c

i t y L e v e

l - -

d B r e

1 0 - 6

i n / s

Figure A-6: Amundson Hall 323 Ambient L eq





70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - - d B r e 1

0 - 6

i n / s

Figure A-7: Nils Hasselmo Hall 7-231A Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e

1 0 - 6

i n / s

Figure A-8: Electrical Engineering & Computer Science 2-270/2-274 Ambient L eq





70

60

50

40

30

20

10

0

1 / 3 O c

t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e 1

0 - 6

i n / s

Figure A-9: Electrical Engineering & Computer Science 1-170 Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e

1 0 - 6

i n / s

Figure A-10: Weaver Densford Hall 8-139B Ambient L eq





70

60

50

40

30

20

10

0

1 / 3 O c

t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e 1

0 - 6

i n / s

Figure A-11: Molecular and Cellular Biology 1-128B Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c

i t y L e v e

l - - d B r e

1 0 - 6

i n / s

Figure A-12: Amundson Hall 54 Ambient L eq





70

60

50

40

30

20

10

0

1

/ 3 O c

t a v e

B a n

d R M S V e

l o c

i t y L e v e

l - -

d B r e 1

0 - 6

i n / s

Figure A-13: Amundson Hall B22 Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c

i t y L e v e

l - -

d B r e

1 0 - 6

i n / s

Figure A-14: Jackson Hall 3-142 Ambient L eq





70

60

50

40

30

20

10

0

1 / 3 O c

t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e 1

0 - 6

i n / s

Figure A-15: Moos Tower 5-108A Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c

i t y L e v e

l - -

d B r e

1 0 - 6

i n / s

Figure A-16: 717 Delaware NMR Lab Ambient L eq





70

60

50

40

30

20

10

0

1 / 3 O c

t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e 1

0 - 6

i n / s

Figure A-17: Weaver Densford Hall 3-119 Ambient L eq


70

60

50

40

30

20

10

0

1 / 3 O c t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e

1 0 - 6

i n / s

Figure A-18: Weaver Densford Hall 3-140 Ambient L eq





70

60

50

40

30

20

10

0

1 / 3 O c

t a v e

B a n

d R M S V e

l o c i t y

L e v e

l - -

d B r e 1

0 - 6

i n / s

Figure A-19: Jackson Hall Room 1-155 Ambient L eq

Ambient Vibration

Documents

Transcript of Ambient Vibration