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PROJECT
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Metro Gold Line Light Rail
Transit System
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LOCATION
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Los Angeles to Pasadena,
California
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CLIENT
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Los Angeles Metro Gold Line
Construction Authority
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Since 1999, ATS has provided acoustical consulting services to the Metro
Gold Line Construction Authority (formerly Blue Line Construction Authority)
on technical, regulatory, legal, and political issues associated with
noise and vibration for a new 14-mile LRT system connecting downtown Los
Angeles with Pasadena.
During this time, our role has included completing a system-wide noise
and vibration assessment in support of the environmental review,
performing site specific noise and vibration testing as part of project
engineering, helping procure special direct-fixation fasteners for
construction, and a variety of key strategic services associated with
legal and regulatory challenges. In addition, ATS participated in or
directed one-on-one and group meetings with citizens, business owners,
and politicians.
ATS has been responsible for resolving noise issues for a variety of
sensitive receptors throughout the three communities served by the
project. One particular concern was the effect of light-rail operations
on a historic movie studio. ATS directed sound insulation tests at the
studio to identify the transmission loss characteristics of specific production
areas. Extensive mitigation, including a 25-foot high sound wall and
building improvements, was implemented to ensure that train noise does
not disrupt filming and audio recording. ATS also prepared technical
analyses for all commercial and residential uses along the alignment. A
key part of many of these analyses was our one-on-one involvement with
concerned community members and organizations in explaining noise
concepts, presenting study results, and discussing mitigation options.
ATS assisted in the transition from final engineering to the design/build
contract and project construction. In particular, the ATS team has been
responsible for gathering and synthesizing project information and
technical data that provided the basis for a new environmental document
and further engineering. The review also required system-wide noise and
vibration analysis based on current design and operational parameters.
As part of project construction, ATS directed a series of vibration
propagation tests for the cut-and-cover tunnel through “Old-Town”
Pasadena. This tunnel structure was constructed adjacent to commercial
and residential buildings, some being historic. State-of-the-art testing
of the local vibration propagation characteristics, combined with previous
testing of the selected light-rail vehicle, also directed by ATS, was
used to predict ground-borne noise and vibration levels inside structures
adjacent to the tunnel. Based on the results, ATS prepared a technical
specification that generated a competitive bid for special
vibration-reducing direct-fixation track fasteners.
ATS also assisted the Authority’s executive management and legal counsel
design and implement a defense for claims regarding noise and vibration.
An action filed with the California Public Utilities Commission (CPUC)
led to a multi-party settlement. As part of this process, ATS provided
expert services and acted as a liaison between the transit authorities,
regulatory agencies, and outside stakeholders involved in the dispute. In
large part, the success of this process was due to our ability to
reasonably interpret and apply standards, to understand the concerns and
objectives of all parties, to clearly communicate technical concepts, and
to engineer a consensus on the critical issues.
The specific commitments in the settlement came from a comprehensive
review of operational noise levels completed by ATS. As traditional
mitigation measures, such as sound walls and residential sound
insulation, had already been installed and many of the complaints were
based on annoyance and not the absolute sound level, ATS investigated
non-standard means to improve local conditions. Our recommendations,
which included minimizing wheel squeal and modifying the grade-crossing
audible-warning devices, were not only cost-effective but also addressed
the root causes of the complaints.
ATS is currently working on the Foothill Extension to
the Gold Line: the Construction Management Team for the Phase 2A
extension to Azusa and the Supplementary EIS/R for the extension from
Azusa to Montclair.
Papers &
Presentations related to this project >>>
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