HomeMy WebLinkAboutM-85-0243To. Clarance Patterson
Assistant City Manager
FROM: Donald W. Cathex
Dine,cctor of P�tbltc�Works
a
January 30, 1985
DATE: F11t:
Metrorail Sound
sue�ECT: Barriers
REFERENCES:
For Commission Meeting
ENCLJSURES:Cf February 14, 1985
Forthcoming is a report on Metrorail Sound Barriers installation
for review and discussion during the Committee of the Whole.
JHJ:az
cc: Alberto Ruder
8S-24
CITY OF MIAMI, FLORIDA
INTER -OFFICE MEMORANDUM
TO: Honorable Mayor, and Members
of the City Commission
FRomr Donald W. Cather
Director of Pubrl"�N Works
DATE: February 6, 1985 FILE:
SUBJECT: Status of Metrorail -
Acoustical Barrier
Installation
REFERENCES:
ENCLOSURES: Listed Below
Following is a review and update on the Status of the Installation
of Acoustical Barriers along Metrorail. Mr. Joseph M. Fletcher,
Executive Director, Metro -Dade Transportation Administration (MDTA)
advises that an advance stock of acoustical barriers are being
installed at various locations along Metrorail. The current stock
of Acoustical Barriers were to be installed in the most critical
noise level areas until this initial stock is exhausted. These
area locations are based on the same descriptor and criteria used
in the Environmental Impact Statement (EIS) for the Metrorail
Project.
Bolt -Beranek and Newman, Inc. (BBN) is MDTA'S Acoustical Consultant
and has prepared a final report. Attached are excerpts and a map
from this November 1984 report which identifies the barrier
location requirements along Metrorail. Please see the map, Figure
4, for Outboard Barrier Locations for the current analysis (1984).
The locations shown is where there will be Acoustical Barriers when
the Barrier Installation is completed.
As of January 28, 1985, from the initial stock of Acoustical
Barriers, 900 Linear Feet (L.F.) of Acoustical Barriers have been
installed on the East Side of Coral Gables Waterway. Approximately
4500 - 5000 L.F. of Acoustical Barriers on -hand remain to be
installed.
The Acoustical Barriers can only be installed during Non -Revenue
Hours, and are currently being installed on weekends.
We are advised that starting the weekend of February 2, 1985
approximately 3500 L.F. of Acoustical Barriers are to be installed
between the Overtown and the Culmer Stations. This segment of
installations will take three weekends to complete. The balance of
the Acoustical Barriers, 1144 L.F. of installation will commence on
February 23, 1985- Installation will be between the Coconut Grove
and the Viscaya Stations at 19-22, Avenues.
Page 1 of 3
85-243
f
Honorable Mayor, and Members February 6, 1985
of the City Commission
(cont'd.)
We recently checked the Barriers installed locations along
Metrorail on the South Leg. There is some linear footage that was
previously installed at locations as follows:
West Side; between S.W. 62 Avenue and 67 Avenue
East & West Side, Coral Gables Waterway
East & West Side, S.W. of Douglas Rd. (S.W. 37 Ave.)
West Side, S.W. of Vizcaya Station and small footage
to the North of the Station
These locations are basically as shown in an Exhibit "A" sketch
marked "Preliminary" as attached to an October 29, 1984 letter to
Don Cather from Mr. Joseph M. Fletcher on the subject Acoustical
Barriers. A copy of this letter is attached.
Also attached are photographs showing the erected Acoustical
Barriers at various locations along Metrorail. Mr. Fletcher
advises that there is approximately 21 miles of Acoustical Barriers
to be installed on a future MDTA Procurement and Installation
Contract. It is planned that this contract will be out for bids
during the month of February, 1985. Due to the advance lead-time
on fabricating the barriers and the restriction of the barriers
being installed during Non -Revenue Hours, the completion of
erecting the barriers is expected to take at least 2 years. The
estimated cost is $14 million.
An erection sequence indicating the areas to be installed on
specific dates has not been determined. Initial plans are to work
in several areas simultaneously.
Page 2 of 3
85-243.
Honorable Mayor, and Members, February b, 1985 !
of the City Commission
(cont'd.)
However, this will depend on delivery commitments from the
Fabricator and availability of Erection Crews of the Contractor.
This Department intends to continue to monitor Acoustical Barrier
installations by MDTA at the .required locations inside of the City
of Miami, and report to you on the installation progress.
.�JHJ:tmk
L
Enclosures: Excerpt from BBN Report
Letter To H. C. Eads, Jr.
Photographs
Exhibits A, B & C
Letter from Metro Dade
Transportation Authority
cc: Randolph B. Rosencrantz,
City Manager
Clarance Patterson,
Assistant City Manager
Page 3 of 3
85— 24a,
Bolt Beranek and Newman Inc.
Report No. 5793
Noise Barrier Analysis for the
Metropolitan Dade County Rapid Transit System
D.A. Towers
November 1984
Prepared for:
Metropolitan Dade County
office of Transportation Administration
85-243,
BBN Report No. 5793
BBN Project No. 05667
NOISE BARRIER ANALYSIS FOR THE
METROPOLITAN DADE COUNTY RAPID TRANSIT SYSTEM
D.A. Towers
November 1984
Prepared for:
Metropolitan Dade County
Office of Transportation Administration
44 W. Flagler Street
Miami, FL 33130
Prepared by:
Bolt Beranek and Neuman Inc.
10 Moulton Street
Cambridge, MA 02233
85-243Y
9.
Report No. 5793
5. NOISE BARRIER REQUIREMENTS
5.1 Noise Barrier Locations
Bolt Beranek and Newman Inc.
The procedure used for determining noise barrier locations
involved the evaluation of transit system and pre -project ambient
noise levls based on the criteria discussed in Sec, 2. Transit
system (Lmax) noise contours were first drawn on aerial photo-
graphs depicting the alignment.* Potential noise barrier loca-
tions were identified by evaluating these contours at noise -
sensitive locations shown on the aerial photographs, based on the
noise criteria. Potential locations for the barriers were then
carefully investigated by means of field inspection surveys and
shielding estimates. in this manner site -specific effects, such
as terrain, building and guideway shielding were evaluated in
order to ensure that the noise barriers will serve the purpose
for which they are intended.
Barrier lengths were selected so that train noise from
beyond the ends of the barrier will not severely compromise noise
barrier acoustical performance at sensitive locations. Barriers
were not extended through the station areas, although there would
be no harm doing so, if desired. This could, in fact, be desir-
able if brake squeal is significant in cases where noise -
sensitive sites are located close to the stations.
In addition to barrier placement on the outboard sides of
the alignment, barrier placement on the inboard side of split
elevated guideway segments was considered on a site -specific
basis. Inboard barriers were recommended only where these would
be effective in significantly reducing transit noise.
The results of the noise barrier location analysis are sum-
marized in Fig. 4 and in Tables 5 and 6. Figure 4 indicates the
approximate outboard locations along the alignment where noise
*Due to their bulk, the aerial photographs and contours are not
included in this report, but have instead been transmitted
directly to MDTA.
14
Report No. 5793
5. NOISE BARRIER REQUIREMENTS
5.1 Norse Barrier Locations
Bolt Beranek and Newman Inc.
The procedure used for determining noise barrier locations
involved the evaluation of transit system and pre -project ambient
noise levls based on the criteria discussed in Sec. 2. Transit
system (Lmax) noise contours were first drawn on aerial photo-
graphs depicting the alignment.* Potential noise barrier loca-
tions were identified by evaluating these contours at noise -
sensitive locations shown on the aerial photographs, based on the
noise criteria. Potential locations for the barriers were then
carefully investigated by means of field inspection surveys and
shielding estimates. In this manner site -specific effects, such
as terrain, building and guideway shielding were evaluated in
order to ensure that the noise barriers will serve the purpose
for which they are intended.
Barrier lengths were selected so that train noise from
beyond the ends of the barrier will not severely compromise noise
barrier acoustical performance at sensitive locations. Barriers
were not extended through the station areas, although there would
be no harm doing so, if desired. This could, in fact, be desir-
able if brake squeal is significant in cases where noise -
sensitive sites are located close to the stations.
In addition to barrier placement on the outboard sides of
the alignment, barrier placement on the inboard side of split
elevated guideway segments was considered on a site -specific
basis. Inboard barriers were recommended only where these — :could
be effective in significantly reducing transit noise.
The results of the noise barrier location analysis are sum-
marized in Fig. a and in Tables 5 and 6. Figure 4 indicates the
approximate outboard locations along the alignment where noise
*Due to their bulk, the aerial photographs and contours are not
included in this report, but have instead been transmitted
directly to MDTA.
14
85-0% 'M .
Report No. 5793
11
Bolt Beranek and Newman Inc.
barriers are required and also indicates those locations where
barriers were indicated in the EIS (1]. Table 5 lists the
lengths of barrier required according to the present analysis and
the EIS. Note that the results for the present analysis include
both sound absorptive and non -sound absorptive barriers on the
outboard side of the guideway'as well as on the inboard side of
split guideway alignment segments. Table 6 provides the civil
station limits and rationale for all required noise barrier loca-
tions. This table also indicates those segments for which sound -
absorptive barriers are recommended, based on the discussion in
Sec. 5.2 below.
i
5.2 Noise Barrier Acoustical Design Concepts
A refinement of noise barrier acoustical design concepts was
undertaken based on a series of measurements performed at an
existing elevated Metrorail noise barrier site in April 1984 (3] .
The results of these measurements have the following implications
with regard to noise barrier acoustical. design:
• The geometrical configuration* of the current outboard noise
barrier design appears to be acceptable; however, the acous-
tical performance of the inboard barrier could be improved
by locating it closer to the guideway rather than at the
edge of the cableway/walkway.
• The existing noise barrier sound transmission loss specifi-
cations (see Table 7) appear to be acceptable. Note that
from an acoustical standpoint, these do not preclude the use
of barrier materials other than steel, such as lightweight
concrete, concrete block, wood, plastic or fiberglass, for
example.
*Distance between car body and barrier, and the height of the top
of the barrier above the top of rail.
15
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SCALA
Figure 4 Barrier Location Requirements
Alignment
Station
Outboard Barrier
Locations
Analysis (Year)
Current (1984)
EIS (1978)
e
Report No. 5793 Bolt Beranek and Newman Inc.
TABLE 5
f LENGTH OF REQUIRED NOISE BARRIERS
Length of Barrier (Ft)
South ,North Hialeah System Total
Barrier Type Corridor Corridor Corridor (Ft) (Mi)
Outboard 55,205 37,085 18,175 110,465 20.92
Inboard 615 10,575 2,185 13,375 2.53
------------------------------------
tion-Absa:�tive 48,760 45,340 18,650 112,750 21.35
Absorptive 7,060 2,320 1,710 11,090 2.10
Total 55,820 47,660 20,360 123,840 23.45
-----------------------------------------------------------------
EIS 38,950 44,600 16,175 99,725 18.89
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17
4 -
3
f
i !1
H. C. Eac=_. jr. November C, 19SA
Assistant City Manacer _
Metrara i I - Acc3u i ca i
Eiarr'i ens
Ccna i d i•f. ;.C�h2r -_�f- _
Dire tor of Publ is `' arks E.::hibitz A, 3 u C
. _. .:as= L.et:er frcm Metrc Cade
Transcorat ion Auth.
At the meting of September 20th, Mayer Feria requested
information on the decibel readings of Metroraii through the City
of Miami. At that tinze the stattment was made that acoustical
barriers had been installed in Coral Gables but not in Miami.
As a fol i ow-u►: to tha';. request met w i th Mr.
Jo.. Fi ,etcher,
fr-xecutive Director of the Metro -Dada Transaortatior,
Adm i r, i st rat i cn and its Chi of Enc i neer Carlos The Mayor
is cor-eC in that the first I?E.O feet of accuse ►cal barriers were
installed ad acent to the Coral Gabies water-way. Thv
Transportation Committee directed Mr. Fletcher's staff to install
the r•ema in i,,a 4500 reel to 5000 feet of acoustical barrier in
stock Rar•t:, o-F the Over•towr. Station to atenuate noise levels in
the cr i t i cal areas adjacent to Metrora i 1 's north I ea_ seamen , i n
x Miami. Tnis section wiIi be going into revenue service an
De_embsr 17th of 'th i s year. The attached :.xh i b i t A shows the
additional areas in which acoustical barriers have been instailad
in the City or Miami. These locations are gust west of Douglas
Road, west of 17th Avenue. east and west of Viccaya Station and
currently being installed are those sections adjacent to
- Jvertcaln. The attached c*xh i b i t A also shows the recommended
locations for acoustical barriers for the entire line includine
the City of Miami. r
Also attached are Exhibits E & C which show the single event
noise levels generated by a Metrorail train passby and are based
an acoustical measurements perforr;ed by their, consultant Solt,
eraneh and Nea;r,iar.. For your information this is the pre-eminent
f i rrn in the field of noise and noise abat ernent in the L1n i t ea
States. The writar has used and wor!.ed with this firm and find
they do excel l ent work which is reliable and based upon many
years of e;:per i ence.
Later this month a report from E-oit, Eeranek and Newman lit iII be
r•ece; vet by t;,e IMOTA at wh i ch t i me they ur i i 1 proceed w i th the'
pr•,apar•at ion of contract documents for barrier procurement and
:nStciiaZiCn.
H. C. ;ads. .Ir..
Assistant City Manager
Noveimber• C. : r34
in summar•v the Metr•c-Cade Transportation Au.hor• i tv is aware of
the sound levels generated which are abcve acceotable design
standards in certain locations and they ans also prepared to
install all necessary_ acoustical barriers to achieve the
standards established by t`'.e Urban Mass irar.aoor•tat ion
Administration. if you still wish to obtain indeoenbent levels
of decibels at the stations other than those obtained by Holt.
Beranek and Newman and represented by E:cn i b i t 6 & C, please'
advise and we ;vi1', proceed accord ingIy.
OWC:mw
cc: Joe Fletcher
A
•
I
f.E-7 METRO-DADE TRANSPORTATION ADMINISTRATION
+ as W Fiagie• Street • Miami. Florlaa 33130
OCT2 91984
Mr. Donald Cather
Director
Public Works Department
City of Miami
275 N.W. 2nd Street
Miami, Florida 33128
Subject: Metrorail - Acoustical Barriers
Dear Mr. Cather:
This is a follow up to our meeting of October 23, 1984, in which we
informed you about the Metro -Dade Transportation Administration (MDTA)
immediate and future plans for Metrorail generated wayside noise atten-
uation through the installation of acoustical barriers.
As you are aware, the Board of County Commissioners' Transportation
Committee directed the MDTA to first install approximately 800-960 feet
of acoustical barriers on the east side of the guideway across the Coral
Gables Waterway. The Transportation Committee also directed that the
remaining acoustical barriers in MDTA's stock (approximately 4500-5000
feet) be installed north of the Overtown station to attenuate noise
levels in the most critical areas adjacent to Metrorail's north leg
segment which extends to the pocket track west of the Earlington Heights
station. As you are aware, this segment is scheduled to be opened for
revenue service on December 17, 1984. You are also aware that the MDT:
has already installed acoustical barriers within the City of Miami as
shown in the attached Exhibit A. Exhibits B and C, also attached, pro-
vide you with single -event noise levels generated by a Metrorail train
pass -by and are based on acoustical measurements performed by the MDTA's
acoustical consultant, Bolt Beranek and Newman, Inc. (BBN).
As I informed you, future acoustical barrier placement will be based on
the same descriptor and criteria used in the Environmental Impact State-
ment for the Metrorail project, that is the American Public Transit
Association (APTA) guidelines for rapid transit train noise levels in
terms of the maximuar A -weighted sound level. Exhibit A represents a
preliminary estimate of barrier requirements throughout the entire sys-
tem based on these criteria. It is anticipated that a final report will
be received from BBN on November 16, 1984. At that time, MDTA will pro-
ceed with the preparation of contract documents for barrier procurement
and installation.
tVteTa0='.'s-klE-PCF;-4-L.•,= •VE1*
WWI
C C
Mr. Donald Cather
Page 2.
As I explained to you, acoustical barriers are long -lead time items
and their installation can be mostly accomplished only during Metro -
rail non -revenue hours. In the meantime, we have initiated steps to
identify potential funding sources that would allow us to proceed with
the procurement and installation phases.
If you need additional information, please advise.
'eincerel ,
Jo a `. Fletcher
Executive Director
J: iF : vmn
Attachments
cc: C.F. Bonzon
6
4
Q,
It
APPROX. 115400 LINEAR FEET
OF BARRIER (assuming ATP cpaccil
BASED ON:
• LMaX DE-SCSIPTOR
• APTA DESIGN GOALS -aw left
==RECO4l.lAYiEr,,'D'!lD LOCATIONS FORCrnC IL
ACOUSTICAL -iA;;;;I--RS
Vw*eASSIRS—FIS CU."IriENTV1 INSTALL M-
C. -,v VI
ot
c.
llk ol
Bolt Beranek and Newman Inc.
ReportNo. 5677
100 ..........................................
1ELEVATED GujcE%,iAYWITH .
IMPECIALZAACK WORK..'!
I
AAVERAGE MEASURED
(2S ft HIGHOF MICROPHONE) DATA
j 95r
.000*
Z so
ca
Lu
Lu
uj
-3
2
76FWA -WITU
14 so
*AVERAGE 6FJ�EASURED oft HIGH MICROPHONE)DATA
AV OERGE OF MEASURED
(5 ft HIGH MICROPHONE) DATA
75
700 20 1 40
1
TRAIN SPEED (-Ph)
FIG. 2.
W=7-92
V-1 �YV-01700
13
.83".PZ43,
I!
Report No. 5677
100
r
Bolt Beranek and Newman Inc. .
AT -GRADE OPEHATIONSJON TRACK
95 SEGMcN" 4Z&�c6�et^
A MEASURED DATA POINTS ./
(5 ft HIGH MICROPHONE) , A A i
/ +
90 ./ r I
O !
z S5
O PO 4
1 AT -GRADE OPERATIONS ON
Ct CONCRETE TIE AND BALLAST CINR
Z TRAC:.°° g'`�!►I ALCy'7 s
ti 8a OMEASURED DATA POINTS
(5 ft HIGH MICROPHONE) 1
1
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I
70 30 40 50 60 70
is 20
TRAIN SPEED (mph) t
FIG. S. SINGLE EVENT LEVELS AT � IN p SBYS ON
18 !`
85�A3,.