TECHNICAL MEMORANDUM

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Rolf Copeland
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1 U-Link: Comparison of Permanent Vibration DATE: November 19, 2015 TECHNICAL MEMORANDUM TO: FROM: SUBJECT: Andy Casillas University of Washington Shankar Rajaram Sound Transit U-Link: Comparison of

1 1 U-Link: Comparison of Permanent Vibration DATE: November 19, 2015 TECHNICAL MEMORANDUM TO: FROM: SUBJECT: Andy Casillas University of Washington Shankar Rajaram Sound Transit U-Link: Comparison of Permanent Vibration System to Certification Test INTRODUCTION As per the Certification Test Operating Agreement OA Exhibit 3 1, Sound Transit conducted side-by measurements of train vibration in the U-Link tunnel using (1) the permanent Vibration System (VMS), and (2) the vibration monitors that were used during the Vibration Certification Tests (referred to as the Certification Test Monitor or CTM in this document). The measurements were performed at three VMS cabinets during controlled test train movements between University of Washington Station (UWS) platform and CP-19. The tests were conducted on August 24-25, 2015, during the VMS transfer function tests. Figure 1 shows the side-by installation of the CTM at one of the VMS cabinet. This memo documents the measurement details and results of these tests. BACKGROUND The permanent VMS units were not ready for use during the Vibration Certification Tests on August 18-19, So during the Certification Tests, temporary vibration monitors called as CTM in this report were installed in the tunnels to measure vibration levels from the test train movements. During the Certification Tests, the CTMs were not located in the VMS cabinets due to logistical reasons. Instead they were mounted in the apron area of the diamond crossover. The 1 Operating Agreement (OA ), Exhibit 3, Permanent Vibration System Compared to Certification, 5 August 2015,

2 2 U-Link: Comparison of Permanent Vibration details of this measurement location are documented in the Certification Test Report 2. As part of the Operating Agreement (OA ), Sound Transit agreed to conduct special tests after the Certification Tests to verify that the performance of the temporary CTM is comparable to the permanent VMS units. Therefore, Sound Transit proposed two potential options for this comparison and the options were documented in Exhibit 3 of the Operating Agreement. Option 2 in Exhibit 3 proposed to do simultaneous measurements using the CTM and the VMS units during the transfer function tests with the CTM mounted in the VMS cabinets. This details of Option 2 execution and the results are presented in the following sections. TEST DETAILS The vibration measurements were performed at the following VMS cabinets: N05-VCC-02, N05-VCC-03, and N05-VCC-05 (See Figure 2) using a four-car test train that was operated for the following train movements: Southbound (SB) non-diverging move departing UWS at 40 mph. Northbound (NB) non-diverging move arriving UWS at 20 mph. Diverging moves across the double crossover at 10 mph. Both NB and SB train movements were performed by the test train in both tunnel bores. The testing was performed between 12:30 AM and 4:30 AM on August 24 th and 25 th. A total of 30 train runs were recorded on each night. Wilson Ihrig Associated (WIA) performed the side-by tests for Sound Transit and analyzed the data. The data from the VMS cabinets was supplied to WIA by International Engineering Machines (IEM), the manufacturers of the VMS hardware and software. The CTMs used either Mark Products geophones or a RT Clark geophone all with nominal sensitivities of 0.75 V/in/sec and a resonance frequency of approximately 4 Hz (RT Clark resonance is at 4.5 Hz). Analog vibration data were recorded on a 4-channel Rion DA-20 digital data recorder. The RT Clark geophone was located at N05-VCC-02 at the center on the NB side of the crossover box. The Mark Products geophones were located at N05-VCC-03 (SB side, north end of crossover box) and N05-VCC-05 (north end of SB station platform). The processing of the test data recorded by the CTM was performed using algorithm that was equivalent to the VMS processing software. The 8-second Leq train vibration spectra for passbys from each of the movement were averaged and compared. 2 Letter of Concurrence: Vibration and Magnetic Fields Certificaiton Testing Acceptance and Approval to Commence Revenuw Service for University Link (Transportation Easement Segment 1), Exhibit 1, Sound Transit U-Link Light Rail Project: Vibration Threshold Compliance Testing at the University of Washington, 5 November 2015,

RESULTS AND CONCLUSION 3 U-Link: Comparison of Permanent Vibration Figure 3 through Figure 11 shows the measured vibration levels using the CTMs at the three VMS cabinets.

Figure 12 shows vibration from train Run#1 that represents a SB non-diverging move departing UWS at 40 mph.

3 RESULTS AND CONCLUSION 3 U-Link: Comparison of Permanent Vibration Figure 3 through Figure 11 shows the measured vibration levels using the CTMs at the three VMS cabinets. A comparison of the results for two train runs measured at cabinet N05-VCC-02 are shown in Figure 12 and Figure 13. Figure 12 shows vibration from train Run#1 that represents a SB non-diverging move departing UWS at 40 mph. Figure 13 shows vibration spectra from train Run#12 that represents a NB non-diverging move arriving UWS at 20 mph. Both train runs were in the SB tunnel and train Run#12 shows a peak that is approximately 5 db lower than Run#1. The lower vibration level for Run #12 is attributed to the lower train speed. The results show that the vibration levels measured by the CTM and VMS were comparable and within 1 db at all 1/3 octave bands. The measured vibration levels were fairly consistent between CTM and VMS units for all train passbys at key frequencies. Therefore, this study concludes that the vibration levels measured by the permanent VMS units are comparable to the measurements from the Certification Vibration Tests. Geophone A of the VMS Unit Geophone B of the VMS Unit Same as Instrumentation Used for Certification Tests Accelerometer Used for Transfer Function Tests Figure 1: Permanent Vibration System Cabinet during Side-by-Side Vibration Measurements

4 4 U-Link: Comparison of Permanent Vibration N05-VCC-03 N05-VCC-05 N05-VCC-02 Figure 2: Vibration Measurement Locations

5 5 U-Link: Comparison of Permanent Vibration Figure 3 Vibration velocity levels measured at monitoring location N05-VCC-02 during 4-car train passbys on NB track (average 8-second L eq )

6 6 U-Link: Comparison of Permanent Vibration Figure 4 Vibration velocity levels measured at monitoring location N05-VCC-02 during 4-car train passbys through crossover (average 8-second L eq )

7 7 U-Link: Comparison of Permanent Vibration Figure 5 Vibration velocity levels measured at monitoring location N05-VCC-02 during 4-car train passbys on SB track (average 8-second L eq )

8 8 U-Link: Comparison of Permanent Vibration Figure 6 Vibration velocity levels measured at monitoring location N05-VCC-03 during 4-car train passbys on NB track (average 8-second L eq )

9 9 U-Link: Comparison of Permanent Vibration Figure 7 Vibration velocity levels measured at monitoring location N05-VCC-03 during 4-car train passbys through crossover (average 8-second L eq )

10 10 U-Link: Comparison of Permanent Vibration Figure 8 Vibration velocity levels measured at monitoring location N05-VCC-03 during 4-car train on SB track (average 8-second L eq )

11 11 U-Link: Comparison of Permanent Vibration Figure 9 Vibration velocity levels measured at monitoring location N05-VCC-05 during 4-car train on NB track (average 8-second L eq )

12 12 U-Link: Comparison of Permanent Vibration Figure 10 Vibration velocity levels measured at monitoring location N05-VCC-05 during 4-car train passing through crossover (average 8-second L eq )

13 13 U-Link: Comparison of Permanent Vibration Figure 11 Vibration velocity levels measured at monitoring location N05-VCC-05 during 4-car train on NB track (average 8-second L eq )

14 14 U-Link: Comparison of Permanent Vibration Figure 12: Vibration Measurements for SB Run#1, SB Tunnel, 12:30 AM, 25 August 2015.

15 15 U-Link: Comparison of Permanent Vibration Figure 13: Vibration Measurements for NB Run#12, SB Tunnel, 12:45 AM, 25 August 2015.

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