HomeMy WebLinkAboutItem 3a: Discussion about Gold Line Sound Wall MaterialDATE: August 17, 2010
TO: Mayor and City Council
STAFF REPORT
Development Services Department
FROM: Jason Kruckeberg, Development Services DirectorD
Philip A. Wray, Deputy Director of Development Servces /City Engineer
By: Linda Hui, Transportation Services Manager
SUBJECT: REPORT, DISCUSSION AND DIRECTION REGARDING GOLD LINE
SOUNDWALL MATERIAL
Recommendation: Provide Direction
SUMMARY
The Development Services Department has been working closely with the Gold Line
Foothill Extension Construction Authority (Authority) in developing project specifications
for inclusion in the construction bid package for the Gold Line. Recently, the City has
been given the opportunity to select a preferred soundwall material from two possible
options which include 1) Fractured -fin Soundwall and 2) Metal Acoustic Soundwall.
After both literature and field reviews on soundwall technology, it is recommended that
the Council approve the Metal Acoustic Soundwall as a preferred technology for the
soundwalls to be placed along the Gold Line alignment in designated areas within the
City.
BACKGROUND
As part of the scope of the Main Alignment of the Gold Line Foothill Extension, areas
abutting residential uses will be equipped with soundwalls. These areas in Arcadia
include portions of the Garden neighborhood, Downtown Hotels and the Arcadia School
District school site and the residential neighborhood east of Bonita Park. Based on the
final Environmental Impact Report and the current preliminary engineering plan, the
soundwalls are required only on the residential side of the track.
DISCUSSION
Traditionally, roadway /railway induced noise has been attenuated with sound barriers
made of masonry (concrete) material. A concrete soundwall can sufficiently reduce
noise if at a minimum the wall is tall enough to block the line -of -sight between the noise
Staff Report
Gold Line Soundwall Material
August 17, 2010
Page 2
source and the receiver. But concrete surfaces tend to reflect noise at a higher decibel
level than the original direct noise source. Noise reflection could be an unintended
issue when there is a soundwall only on one side of the noise source. To address the
noise reflection issue, sound absorptive technologies such as a metal acoustic
soundwall have become a viable option. Metal acoustic soundwalls are coated steel
modular panels filled with fiberglass, non - corrosive, weather -proof acoustic material for
sound absorption. The panel coating comes in multiple colors and is graffiti resistant.
The panels are easily replaceable.
Installation of a metal acoustic soundwall along the Gold Line in South Pasadena has
been successful and has served as a basis for viable soundwall alternative for the Gold
Line extension. Thus, the Authority has given the City an opportunity to choose from
two viable soundwalls options — fractured -fin and metal acoustic soundwalls. (See
Attachments for photographs). Based on information received and field inspections, the
metal soundwalls are a preferable alternative both in terms of appearance and
performance.
FISCAL IMPACT
No fiscal impact is anticipated.
RECOMMENDATION
Staff recommends that the Council approve the Metal Acoustic Soundwall as a
preferred technology for the soundwalls to be placed along the Gold Line alignment in
designated areas within the City.
Approved: P
JK:PAW:LH:pa
Donald Penman, City Manager
Attachments: Photographs of Metal Acoustic Soundwalls and Fractured Fin Concrete
Soundwalls
Attachment
Soundwall Examples
Fractured -fin Soundwall
Metal Acoustic Soundwall
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Attachment
Metro Gold Line — South Pasadena
BNSF — Anaheim