Vibration Monitoring for University Of Louisville Belknap Campus Master Plan Seven Locations

Transcription

1 REPORT TO: Mr. Kenneth Dietz University Architect & Director Planning Design & Construction University of Louisville 421 West Cardinal Blvd. Louisville, KY SUBJECT: Vibration Monitoring For University of Louisville Belknap Campus Master Plan Seven Locations PREPARED BY: Mohamad Sharif, PE Brian C. Warner DATE: December 2, 2008

2 TABLE OF CONTENTS EXECUTIVE SUMMARY Page 1 INTRODUCTION OBJECTIVES SCOPE OF WORK Page 2 Page 2 Page 2 INSTRUMENTATION ANALOG TO DIGITAL RECORDER SPECTRUM ANALYZER ACCELEROMETER TRANSDUCERS Page 3 Page 3 Page 4 Page 4 TEST PROCEDURE Page 5 VIBRATION CRITERIA AISC GENERIC VIBRATION CRITERIA NIH VIBRATION GUIDE Page 8 Page 8 Page 10 RESULTS Page 11 CONCLUSION Page 15 APPENDIX Page 16

3 EXECUTIVE SUMMARY The University of Louisville planes to construct a new research facility near its Belknap Campus. There are seven potential sites for the selection of the proposed research facility. The proposed facility will house numerous types of equipment whose operations are sensitive to vibration. Vibra-Tech Engineers was retained by the University of Louisville to measure ambient and nearby train induced ground vibration at these sites. The American Institute of Steel Construction (AISC), the Institute of Environmental Sciences (IES), and the National Institutes of Health (NIH) has provided generic vibration guidelines to aid architects and engineers in the design of research facilities. Their recommendations use the 1/3-octave velocity metric. These guidelines are valuable in the preliminary design phase and in the absence of specific equipment vibration criterion. They also provide a common set of units that the design team can communicate the requirements of vibration levels within the structure. This report will follow the vibration criteria recommended by AISC. Ambient vibration was monitored continuously from approximately 8:00 AM to 5:00 PM for each location. Digital time history data was then analyzed using a spectrum analyzer. The spectrum analyzer was placed in one-third-octave band mode. Calculations have been performed to classify the percentage of time that the sites meet different class of vibration criteria recommended by AISC (VC-E to VC-A). The results of the analysis indicate that Train induced vibration amplitudes may be lowest at the following locations: Parrish House U of L Floyd Street Property Hahn Street & Eastern Parkway Area The linear frequency analysis of recorded vibration data collected at Hahn Street & Eastern Parkway Area shows the presence of steady state vibration primarily in the East- West direction with a dominant frequency of approximately 12 Hertz. It is believed that this type of vibration may be the result of the operation of mechanical equipment located at the adjacent food processing facility. In the absence of this facility the overall vibration level at this location may be reduced. Our observation at the Parrish House indicates that the majority of recorded ground vibration is due to vehicle traffic at Boxley Avenue. The vibration sensors were located within 20 feet of the road. The transmissibility of these types of traffic induced ground vibration to the research facility will be attenuated. - 1

4 1-1 Objectives: 1- INTRODUCTION The purpose of this study is to determine the effects of ground vibration induced by train traffic and existing ambient vibration levels at seven different sites surrounding the University of Louisville Belknap Campus. 1-2 Scope of Work: The following scope of work is provided for this study: Measurement of ground vibration at the seven proposed site locations in three orthogonal directions. The following sites were monitored: 1. Kentucky Trailer Location #1 2. Kentucky Trailer Location #2 3. Churchill Park 4. Parrish House 5. U of L Bloom and Floyd Street Property 6. U of L Floyd Street Property 7. Hahn Street & Eastern Parkway Area Calculation of percentile based one-third octave band vibration velocity spectrums for each measurement site. Comparisons of data with the AISC design guide for sensitive laboratory equipment. Preparation of final report - 2

5 2-1 Analog to Digital Recorder: 2-INSTRUMENTATION Accelerometer sensors were connected to a 16-channel analog to digital recorder. The high speed 16 Bit A/D allows for analog vibration time history data to be recorded at rates up to 100 khz. A/D Specs: Type: Successive approximation Resolution: 16 Bit Linearity: +- 1 Bit Zero Drift: ± 10 PPM/ C Gain Drift: ± 30 PPM/ C Acquisition : 2µs Amplifier: Frequency Range Gain = Hz - 30 khz Gain = Hz - 10 khz Noise Gain = 1 (30 khz) 70µV rms Gain = 100 (10 khz) 1,500µV rms - 3

6 2-2 Spectrum Analyzer: Spectrum analyzer measurement equipment used in the study consisted of a portable computer with a spectrum analyzer interface board and programmable digital filters. Vibra-Tech s data collection/archival system allows for collection and archiving of vibration data in both the time and frequency domains as well as signal processing features which aid in analysis of both random and periodic vibration phenomena. The transducers used for conversion of physical vibration phenomena into analog current/voltage signals were Wilcoxin Research model 731 ultra low frequency seismic accelerometers and model P31 Power Unit Amplifier/Filter. This system has the capability to measure to the sub-micro g level. The system is particularly suited for the measurement of low level vibration as in optical and photographic stability monitoring, electron microscope, microtome and vibration isolation table monitoring. The following are the system specification: Bandwidth Hz Hz df = Hz 2-3 Accelerometer Transducers Accelerometer Model 731 Voltage Sensitivity: 10 V/g Frequency Response: 0.12 Hz Hz 0.08 Hz Hz 0.04 Hz Hz Mounted Resonance Max Amplitude Range 0.86 khz 0.5 g Peak - 4

7 3-TEST PROCEDURE Vibra-Tech Engineers measured ambient and ground induced train vibration at the following seven locations. 1. Kentucky Trailer Location #1 2. Kentucky Trailer Location #2 3. Churchill Park 4. Parrish House 5. U of L Bloom and Floyd Street Property 6. U of L Floyd Street Property 7. Hahn Street & Eastern Parkway Area Vibration measurements were conducted using high sensitivity seismic accelerometer sensors, analog to digital recorders, and spectrum analyzers. Ground to sensor coupling was achieved by placing the accelerometer sensors a depth of one to two feet below the soil. Monitoring was conducted at each location for approximately 8 hours between the periods of 8:00 AM and 5:00 PM. The following table and figure illustrate the measurement locations. Location KY Trailer Location #1 KY Trailer Location #2 Churchill Park Parrish House Table 3-1 Vibration Monitoring Locations Coordinates N W N W N W N W Train North (ft) Train South (ft) Train East (ft) Train West (ft) Nearby Road (ft) I Boxley 100 Floyd U of L Bloom and Floyd Street Property U of L Floyd Street Property Hahn St and Eastern Pkwy Area N W N W N W Bloom 120 Floyd Floyd Floyd - 5

8 Complete time history vibration recordings were collected for train traffic passing on the nearby tracks. Also, ambient vibration was monitored continuously from approximately 8:00 AM to 5:00 PM per location. Digital time history data was then analyzed using a spectrum analyzer. The spectrum analyzer was placed in one-third-octave band mode and a frequency bandwidth of 125 Hz. Calculations have been performed to classify the percentage of time that the sites meet different class of vibration criteria recommended by AISC (VC-E to VC-A). Figure 3-1 shows the aerial photo of the vibration monitoring locations. - 6

9 Figure 3-1 Vibration Monitoring Locations - 7

10 4-VIBRATION CRITERIA 4-1 AISC Generic Vibration Criteria: In the absence of vibration criterion for specific equipment, the generic vibration criteria can be used. The generic vibration criterion recommended by the Institute of Environmental Sciences is IES-RP-CC012.1 entitled Considerations in Clean Room Design 1 and is followed by AISC 2. Chapter 6 of the AISC guide line is about recommended vibration criterion for sensitive equipment. This report will follow the vibration criteria recommended by AISC. The following table and figure are applied to footfall-induced vibration that is copied from AISC document: Table 4-1- Vibration Criteria for Sensitive Equipment (From AISC) Facility Equipment or Use Vibration Velocity Computer system; Operating Room; Surgery; Bench microscopes at up to 100X magnification (µin/s) (µm/sec) 8, Laboratory robots 4, Bench microscopes at up to 400X magnification; Optical and other 2, precision balances; Coordinate measuring machines; Metrology laboratories; Optical comparators; Microelectronics manufacturing Class A Micro surgery, eye surgery, neuro surgery; Bench microscopes at 1, magnification greater than 400X; Optical equipment on isolation tables; Microelectronics manufacturing equipment - Class B Electron microscopes at up to 30,000X magnification; Micro-tomes; Magnetic resonance imagers; Microelectronics manufacturing equipment - Class C Electron Microscopes at up to 30,000X magnification; Mass spectrometers; Cell implant equipment; Micro-electronides manufacturing equipment - Class D Microelectronics Manufacturing equipment; Un-isolated laser and optical research system - Class E Institute of Environmental Sciences, Considerations in Clean Room Design IES-RP-CC012.1 (1993). 2 Thomas M. Murray, PhD, David E. Allen, PhD, and Eric E. Ungar, ScD Floor Vibrations Due to Human Activity, Steel Design Guide Series, Chapter 11, Second Printing October

11 Figure 4-1 General Vibration Criteria Curves to be used with Values of Table 4-1 (From AISC) - 9

12 4-2 NIH Vibration Guide: Space or Equipment Type Vibration Velocity Limit (µin/s) General Office 7,874 Computer Systems 7,874 Animal facility procedure areas 1,969 General Laboratory 1,969 Rodent behavioral 1,969 Micro-Surgery 984 Ordinary Surgery 984 Animal Research Facility 7,874 Microscope Core (EM Laser) 984 Laser-based optical system 472 Super microscope very low should be slab on grade Slab on grade MRI and NMR slab on grade Slab on grade Above grade 472 Steel-framed buildings often require increased design live load to allow for times the weight of the instrument for an inertia block. Electron microscope greater than 30,000 X mag, mass spectrometers, cell implant 236 Eye surgery, neurosurgery 984 Bench Scopes up to 100X mag 1,969 Electron microscopes 472 Bench microscopes greater than 400X mag and optical equipment on isolation tables 984 The NIH vibration Guide is presented in this report for additional information for the reader. This report will follow the vibration criteria recommended by AISC. - 10

13 5-RESULTS Ambient and train induced ground vibration was monitored between October 27,2008 to October 30, The continuous ground vibration monitoring was started at approximately 8:00 AM and ended at 5:00 PM at each site. Digital time history data was then analyzed using a spectrum analyzer. The spectrum analyzer was placed in one-thirdoctave band mode. Calculations have been performed to classify the percentage of time that the sites meet the vibration criteria levels of VC-E to VC-A which is recommended by AISC. The results are shown in the following six tables. Tables with Ambient in the title indicate that the analysis is of the entire day (8:00 AM to 5:00 PM) of collected vibration data including all train events. Tables with Train Vibration in the title are the analysis of only periods when trains were observed passing the monitoring location. For examples, the table Vertical Ambient Vibration Level at KY Trailer Location #1 was monitored for 8.2 hours. For 78.94% of the time, the measured vertical vibration levels met the AISC VC-E vibration criteria. This level includes all passing trains, and vehicle traffic. From the next table Vertical Train Vibration Level, 56 minutes of the recording period were during the pass-by of trains on all adjacent tracks. During the train passing periods the site only met the VC-E criteria 16.71% of the time. Measurement Location Table 5-1A -Vertical Ambient Vibration Level Percent of Meets > VC-A (%) Percent of Meets VC-A (%) Percent of Meets VC-B (%) Percent of Meets VC-C (%) Percent of Meets VC-D (%) Percent of Meets VC-E (%) Record (Hrs) KY Trailer Location # KY Trailer Location # Churchill Park Parrish House U of L Bloom and Floyd Street Property U of L Floyd Street Property Hahn St and Eastern Pkwy Area

14 Measurement Location Table 5-1B - Vertical Train Vibration Level Percent of Meets > VC-A (%) Percent of Meets VC-A (%) Percent of Meets VC-B (%) Percent of Meets VC-C (%) Percent of Meets VC-D (%) Percent of Meets VC-E (%) Train Record (Min) KY Trailer Location # KY Trailer Location # Churchill Park Parrish House U of L Bloom and Floyd Street Property U of L Floyd Street Property Hahn St and Eastern Pkwy Area Measurement Location Table 5-2A - Horizontal North-South Ambient Vibration Level Percent of Meets > VC-A (%) Percent of Meets VC-A (%) Percent of Meets VC-B (%) Percent of Meets VC-C (%) Percent of Meets VC-D (%) Percent of Meets VC-E (%) Record (Hrs) KY Trailer Location # KY Trailer Location # Churchill Park Parrish House U of L Bloom and Floyd Street Property U of L Floyd Street Property Hahn St and Eastern Pkwy Area Measurement Location Table 5-2B - Horizontal North-South Train Vibration Level Percent of Meets > VC-A (%) Percent of Meets VC-A (%) Percent of Meets VC-B (%) Percent of Meets VC-C (%) Percent of Meets VC-D (%) Percent of Meets VC-E (%) - 12 Train Record (Min) KY Trailer Location # KY Trailer Location # Churchill Park Parrish House U of L Bloom and Floyd Street Property U of L Floyd Street Property Hahn St and Eastern Pkwy Area

15 Measurement Location Table 5-3A - Horizontal East-West Ambient Vibration Level Percent of Meets > VC-A (%) Percent of Meets VC-A (%) Percent of Meets VC-B (%) Percent of Meets VC-C (%) Percent of Meets VC-D (%) Percent of Meets VC-E (%) Record (Hrs) KY Trailer Location # KY Trailer Location # Churchill Park Parrish House U of L Bloom and Floyd Street Property U of L Floyd Street Property Hahn St and Eastern Pkwy Area Measurement Location Table 5-3B - Horizontal East-West Train Vibration Level Percent of Meets > VC-A (%) Percent of Meets VC-A (%) Percent of Meets VC-B (%) Percent of Meets VC-C (%) Percent of Meets VC-D (%) Percent of Meets VC-E (%) Train Record (Min) KY Trailer Location # KY Trailer Location # Churchill Park Parrish House U of L Bloom and Floyd Street Property U of L Floyd Street Property Hahn St and Eastern Pkwy Area

16 The complete vibration data are presented in the appendixes of this report. These appendixes are as follow: Appendix I Kentucky Trailer Location #1 Data Analysis. Appendix II Kentucky Trailer Location #2 Data Analysis Appendix III Churchill Park Data Analysis Appendix IV Parrish House Data Analysis Appendix V U of L Bloom and Floyd Street Property Appendix VI U of L Floyd Street Property Appendix VII Hahn Street & Eastern Parkway Area In addition the results page for the seven-location vibration study performed for the University in July of 2002 has been included in Appendix VIII. - 14

17 6-CONCLUSION The major sources of the ground vibration at the proposed site were the nearby railroads for freight train traffic and the vehicle traffic on highway I-65. Vibra-Tech personnel s monitored ambient and train induced ground vibration continuously from approximately 8:00 AM to 5:00 PM for each proposed site. Digital time history data was then analyzed using a spectrum analyzer. The spectrum analyzer was placed in one-third-octave band mode. Calculations have been performed to classify the percentage of time that the sites meet different class of vibration criteria recommended by AISC (VC-E to VC-A). The results of the analysis indicate that Train induced vibration amplitudes may be lowest at the following locations: Parrish House U of L Floyd Street Property Hahn Street & Eastern Parkway Area The linear frequency analysis of recorded vibration data collected at Hahn Street & Eastern Parkway Area shows the presence of steady state vibration primarily in the East- West direction with a dominant frequency of approximately 12 Hertz. It is believed that this type of vibration may be the result of the operation of mechanical equipment located at the adjacent food processing facility. In the absence of this facility the overall vibration level at this location may be reduced. Our observation at the Parrish House indicates that the majority of recorded ground vibration is due to vehicle traffic at Boxley Avenue. The vibration sensors were located within 20 feet of the road. The transmissibility of these types of traffic induced ground vibration to the research facility will be attenuated. It is our opinion that the aforementioned locations may be suitable for construction of a research facility. The structural engineer for the project should consider the existing ground vibration at the selected site to properly design a foundation system to minimize ground vibration transmissibility to the structure. - 15

18 Appendix I Kentucky Trailer Location #1 Data Analysis - 16

19 Kentucky Trailer Location #1-17

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26 Appendix II Kentucky Trailer Location #2 Data Analysis - 24

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34 Appendix III Churchill Park Data Analysis - 32

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42 Appendix IV Parrish House Data Analysis - 40

43 Parrish House - 41

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50 Appendix V U of L Bloom and Floyd Street Property - 48

51 U of L Bloom and Floyd Street Property - 49

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58 Appendix VI U of L Floyd Street Property - 56

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66 Appendix VII Hahn Street & Eastern Parkway Area - 64

67 Hahn Street & Eastern Parkway Area - 65

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74 Appendix VIII Results of July 2002 Seven-Location Vibration Study - 72

75 4-RESULTS & CONCLUSION Maximum, Mean and Minimum vibration level in average mode and peak mode is calculated for the entire 7.5 hours of the vibration monitoring. Figures 4-1 through 4-12 graphically shows the results. It should be notice the recommended vibration criterion is 250 µin/s. The following table describes our opinion for potential construction of a nanotechnology research facility per site. Table 4-1 Site Vibration Evaluation Site Shelby Campus Stoddard Johnson School Quad Health and Science Center Reynolds Building Graphic Building Whip-Mix Opinion This site is excellent for nano-technology. It will also meet the difficult class E (125µin/s) vibration criteria Most of the vibration at this site induced by traffic at Bradley street. The traffic vibration is exaggerated by a pump on the street. The maximum average vibration at this sit is 120 µin/s. The mean peak vibration is 565 µin/s. We believe that this site can easily meet class D (250 µin/s) vibration criteria with some modification to Bradley street. The maximum average and mean peak ambient vibration at this site are 239 µin/s and µin/s respectively. The maximum average and mean peak train induced vibration is 250 µin/s and 1,048 µin/s respectively. Even though the vibration amplitude at this location exceeding the 250 µin/s recommended vibration criteria, it is our opinion that by properly designing the building s foundation and placing the research center at its basement, the site has the potential to meet class D (250 µin/s) vibration criteria The ambient and train maximum average vibration is below 250 µin/s. The mean peak vibration is about 400 µin/s. The dominated ambient horizontal vibration frequency is at 3.15 Hertz band. Due to the presence of low frequency vibration at this site, the vibration amplitude will be amplified as it enters to the building. It may be a difficult task to meet 250 µin/s vibration criteria at this site. The ambient and train vibration was monitored at northeast corner of the first floor of this building. The ambient vibration will meet class D vibration criteria. However, the train-induced vibration is in excess of 2000 µin/s, which is well over the recommended vibration criteria. The ambient and train vibration exceeds the recommended vibration criteria. This site is not suitable for nano or micro fabrication facility The ambient and train vibration by far exceeds the recommended vibration criteria. This site is not suitable for nano or micro fabrication facility - 73