Ramon E. Nugent, P.E. Acentech Inc.

Ramon E. Nugent, P.E.
Acentech Inc.
TRB ADC40
Conference
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Because of the sensitive nature of the
unresolved issues related to the project, the
preparers of the EIR/EIS noise and vibration
study, the Contractor, the Contractor’s noise
and vibration consultant, and the Owner of
the LRT line, the name of the LRT line will not
be identified.
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TRB ADC40
Conference
Please do not speculate or ask.
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Background
Our Role
Measurement
Measurement
Measurement
Measurement
Status
TRB ADC40
Conference
System
Procedure
Results – Noise
Results – Vibration
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8.6 miles of double track
10 new stations
Existing noise and vibration measurements in
2000 and supplemented in 2004
Final noise and vibration report in 2005
Environmental documents approved in 2006
Construction 2006 to 2012
Powered electrically with overhead catenary
wires
TRB ADC40
Conference
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Used measurements of existing Siemens
Transportation Systems P2000
Assumed:
 three-car trains from 06:-09: and 15: to 19:
◦ one-car trains 05: to 06: and 21: to 01:
◦ two-car trains remainder of day
 Assumed Lmax (1 dBA less than FTA Recommendation):
◦ 77 dBA at 40 mph
◦ 78.4 dBA at 55 mph
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Headways:
◦ Peak hours = 5 minutes
◦ Off-peak hours = 12 minutes
TRB ADC40
Conference
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Forced density measurements of existing Siemens
Transportation Systems P2000 at 40 mph
Transfer mobility measurements
Calculated Maximum Vibration Levels at 55 mph
speed using above plus an Unknown safety factor
Possible impacts
projected within
approximately
140 ft
Identified Noise Impacts
Moderate
Identified Vibration Impacts
Severe
Severe
SF
MF
SF
MF
SF
MF
60
6
49
0
150
23
Noise
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Noise Barriers
◦ 2710 feet 8-ft
◦ 5940 feet 6-ft
◦ 760 feet of 4-ft on
elevated structure
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Reduce crossing bells
to 60 dBA at 50 ft
Sound insulate Homes
TRB ADC40
Conference
Vibration
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7,300 feet of track
mitigation
Spring-rail or
movable point frog at
crossovers
Relocating crossovers
“No residual impacts”
“all noise and vibration
impacts have been
mitigated to levels that
meet FTA noise and
vibration impact criteria.”
TRB ADC40
Conference
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Provide an Independent noise and vibration
evaluation
◦ Measure noise emissions
◦ Calculate full service Ldn at noise sensitive
receivers along ROW
◦ Measure maximum vibration levels of LRT
◦ Quantify the potential of residual noise and
vibration impacts
◦ Do it quickly
TRB ADC40
Conference
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Real Time Analyzers
◦ 1-second RMS Time History
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Vibration sensor attached
to ground stake
◦ 50 mV/G sensitivity
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Microphones
◦ ½” microphone
◦ Windscreens
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Calibrated using NIST
traceable standards
TRB ADC40
Conference
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Take advantage of LRT operator training
◦ Actual trains
◦ Actual speeds
Selected 19 residential locations along ROW
where impacts were identified and mitigation had
been installed
Measure maximum ground-borne Vibration
Measure SEL at two heights
◦ First story elevation
◦ Second story elevation
Collect representative sample (5 pass-bys in each
direction)
TRB ADC40
Conference
TRB ADC40
Conference
TRB ADC40
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TRB ADC40
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TRB ADC40
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Acentech Report submitted to Contractor
Grand opening occurred in late April
Ridership has been a success
Contractor still finishing punch list
Waiting for meeting to discuss noise &
vibration issues
◦ Expect discussions to begin in August
TRB ADC40
Conference
TRB ADC40
Conference