2 Noise Study Lewis EngineeringCITYOF
CHAN SEN
690 G7 Cemer Drive, PO Box I47
GJ,mhasseJ~, Mimtesom 55,317
Pt,o,e 612.937,1900
Geno~d bkx 612.937.5739
E~gineeri,g Fax 612.937.9152
P, blic S~O, ht.x' 612.934.2524
it:~b tt,~,t~ ti. cha~l~asse~.,m.
MEMORANDUM
TO:
FROM:
DATE:
SUB J:
Todd Gerhardt, Acting City Manager
Kate Aanenson, AICP, Planning Director
January 13, 1999
Lewis Engineering Noise Study
The city council authorized David Braslau to conduct a noise study of Lewis
Engineering located in Chaska. The study was precipitated by the residents of
Trotters Ridge who were unsuccessful in dealing with the City of Chaska and
Lewis Engineering to reduce the noise. City staff, Don Ashworth and Mayor
Mancino met with Chaska City Manager Dave Porkorney to discuss this issue.
Chaska has stated that they would be willing to work with the City of Chanhassen
to help resolve this situation but they have not made any commitment regarding
costs.
The first step in the process is to review the noise study and determine some
possible alternatives. Attached please find the Braslau study. Staff will review
the study with the council and discuss some possible alternatives. Staff is seeking
direction from the city council.
The City qf CTmuhasse,, ,4 ,growi~g comm~jjiO, with c/c~J: /~d,'es, q~.~,diO, sd~oo& a ch~J7~i~g downtown, 3riving busi~esses, and beaut~d p~rks. A great place to live, work, artd play.
DRIVE
HIGHWA
o 0
82ND STREET
_ LYMAN
i=
BLVD.~
8700--
0 0 0 0
0 0 0 0
8800--
(C.R. 18)
DEC 10 1998 12:08 FR DAVID BRASLAU ASSOC 612 331 45?2 TO 9375?39 P.02/08
david brlll~~u b aaaaalmt~lm,
~;elephone: 512~,_~11-~571 · fax:
10 December 1998
TO: Cynthia Kirchoff
FROM: David Braslau
Lewis Engineering - Noise Control Study
This short interim memorandum describes the current study status.
Establishment of Geometry..,artdEl_~y~ations
A number of different sources were needed to establish a sufficiently accurate layout with
elevations for a the barrier study to be meaningful. These included:
USGS Topographic map (on CD)
· Metropolitan Council aerial photo (on CD)
· Lewis Engineering building plans and elevations
Residential site surveys
Since all of the above were in different scales and formats, considerable effort was needed to
establish the layout. This is shown on Attacttment 1 First and second floor elevations were
assumed to be 5 and 14 feet above ground elevation.
Assumption on No!s.e...S.q.u. ree(s~
The observed sound source was a loader although other equipment may be used. No attempt was
made to evaluate impact nobe within the scope of this study. A source sound level of 85 dBA at
50 feet was assumed for the yard equipment. Since no specific information on location of
activity within the yard is available, seven locations distributed from north to south within the
yeard were analyzed. These sites are indicated on Attachment 1.
Calculation,.pf Barrier Effectiveness
In order to begin the analysis, an initial barrier height of 15 feet above ground elevation was
assumed. Two barrier locations were analyzed, one along the edge of the storage area and the
other along the berm just west of the residential area. Effectiveness for both 1 st and 2nd story
elevations was calculated. The attached charts show the predicted noise level with and without
the barrier, the barrier benefit (in dBA) and the effective barrier height relative to the sound
source and receptor site. There is relatively little difference between 1st and 2nd floors for the
"Building Wall". since the source elevation is assumed constant and relatively close to the wall.
The "Berm Wall" is more effective for the 1st floor, since the 2nd floor is high relative to the
barrier height. Some further analysis of these alternatives will be made within the limitations of
the study scope.
DEC 10 1998 12:01FR DAUID BRASLAU ASSOC 612 3~1 4572 TO 9375739 P.03/08
Cynthia Kirehoff on Lewis Engineering Noise Control Study
I 0 December 1998
Page 2
Estimation of,.B,.arrier Costs
An initial estimate of barrier costs has been made, assuming a 15 foot high wall located along the
storage area and along the berm. The wail length was chosen to provide attenuation to the five
homes shown on Attachment 1. For the "Berm Wall", two alternatives were assumed: (1) a full
height wall (15 feet) from the ground with no advantage from the existing berm, and (2) a 10
foot high wall on top of the berm (assumed to be 5 feet high). The following approximate costs,
based upon rule of thumb estimates, were developed'.
Building Wall (length 660 feetYl5 feet high)
Berm,Wall (length 580 feet/15 feet high)
(located at berm but full height barrier)
Berm Wall (length 580 feet/10 feet high)
(loom:ed on top of berm)
** A 5-foot high berm with no grading or
improvement to support the wall is assumed
$148,500
$130,500
$ 58,000**
chart 1210-mere.doc 98083
DEC i8 1998 i2:02 ~R DAUID BRASL~U ~SSOC
331 4572 TO 9375739
L~ S'~O~
P. 04/88
.t~,? o F'I" t
ATTACHMENT 1
Layout of Lewis Engineering and Adjacent Residences
DEC: 10
1998
1~,0~ FR DRUID
BReSLaU ~SSOC 612 ~1 4572 TO
BLDG WALL -1ST
P.05/08
ocAT oN
2503
249g
2495
2491
2483
~-OCATION
--' 25o '
2499
2495
2491
2483
LOCATION
2503
2499
2495
2491
2483
LOCATION
2503
2499
2495
2491
2483
N
62.9
65.0
65.5
66,5
64.9
N
71,9
73,0
73.5
73,5
71.9
N
9
8
8
7
7
PREDICTED NOISE LEVELS with barrier (dBA)
NE ENE E ESE SE
63,0 63.9 63,5 63,3 62,0
63,2 65,3 64,8 63,3 62,9
66.3 66,1 64,6 64,3 62,7
66,3 66,7 65,3 64,0 63,3
65,5 64.8 65.5 64,8 63.5
61.5
62,4
63.1
63.7
64,4
"DOOR
54.8
55,8
56,8
57.1
57,0
PREDICTED, ,NOISE LEVELS. with NO ~barrier (dBA)
NE ENE E ESE SE
73,0 71,9 70,5 69.3 68,0
73,2 73.3 71,8 70,3 68,9
75,3 74,1 72,6 71.3 69,7
75.3 74,7 73.3 72.0 70.3
73.5 73,8 73,5 72,8 71,5
s
67,5
68.4
69,1
69,7
70.4
DOOR
60,8
61.8
62,8
63,1
63.0
TABLE OF BARRIER BENEFITS (dBA)
NE ' ENE E ESE S'F.
10 8 7 6 6
10 8 7 7 6
9 8 8 7 7
9 8 8 8 7
8 9 8 8 8
DOOR
6
6
6
6
6
TABLE OF EFFECTIVE BARRIER HEIGHTS (feet)
N NE ENE E EsE SE $ DOOR
9,4 9,4 9,6 9.6 9.6 9,6 10.0 6.3
9,5 9.4 9.6 9,7 9,7 9,7 10.1 7.6
9,9 9.7 9.7 9.7 9,6 9.6 10.1 7,6
10.1 9.6 9.6 9.6 9,6 9,6 10.1 7.5
9.9 9,6 9,5 9,6 9.5 9.5 9.9 7.2
11/18/98-8:35 AM-E~arrcalc,xls
DEC 10 i998 12:83 FR DRUID BRRSLRU RSSOC 612 331 4572 TO 9375739
P.06/08
BLDG WALL-2ND
PREDICTED NOISE LEVELS with barrler(dBA~)
LOC-ATI'~N .... N NE ~NE E ESE SE
2503 63.9 65.0 65.9 64.5 65,3 62,0
2499 66,0 65.2 67,3 65,8 64.3 62.9
2495 67,5 68.3 67,1 66.6 65.3 63,7
2491 67,5 68,3 67,7 67.3 66.0 64.3
2483 65,9 66.5 66.8 66.5 65.8 65.5
61.5
62.4
63.1
63.7
64,4
o0ba
54.8
56,8
56.8
57.1
57.0
LOCATION
,,?REDICTED NOISE LEVELS with NO barrier (dBA)
ESE SE
S DOO~
2503 7t.9 73.0 71.9 70.5 69.3 68,0 67.5 60,8
2499 73.0 73.2 73.3 71,8 70,3 68,9 68,4 61,8
2495 73,5 75,3 74.1 72.6 71.3 69,7 69-1 62,8
2491 73.5 75,3 74.7 73,3 72.0 70.3 69,7 63.1
2483 71.9 73.5 73,8 73.5 72.8 71.5 70.4 63.0
, TABLE OF BARRIER BEN~EFITS (dBA)
LOCATION N NE ENE - E ESE SE'" $ DOOR
2503 8 8 6 6 6 6 6 6
2499 7 8 6 6 6 6 6 5
2495 6 7 7 6 6 6 6 6
2491 6 7 7 6 6 6 6 6
2483 6 7 7 7 7 6 6 6
TABLE OF EFFECTIVE BARRIER HEIGHTS (feet)
LOCATIO~ N NE EI~E E ESE SE
2503 8.2 8,2 7,7 7.8 7.8 7.9
2499 8.0 8,2 7,7 7.7 7.7 7.7
2495 7,3 7,6 7,7 7,6 7,7 7.7
2491 6.9 7.8 7.7 7.7 7,7 7.7
2483 7,1 7.9 7,9 7,9 6,0 7,9
S DOOR
7,0 4.6
6.7 4,3
6.8 4.3
6,8 4,8
7.1 4,4
11/18/98-8:3§ AM-Barrcalc.xls
331 457~ TO RB?573R ~.07/0~
LOCATION
2503
2499
2495
2491
2483
62.9
62.0
62,5
62,5
63,9
LOCATION
' 2' 03
2499
2495
2491
2483
N
71,9
73.0
73,5
73.5
71.9
LOCATION
2503
2499
2495
2491
2483
BEEM WALL-1ST
LOCATION
2503
2499
2495
2491
2483
N
11,4
11,6
11,5
11,5
11,1
PREDICTED NOISE LEVELS with barrier(dBA)
NE ENE E ESE SE
65,0 63,9 62,5 62,3 62,0
65,2 62-3 62,8 62,3 62,9
64,3 64,1 62.6 63,3 61,7
65.3 64,7 63,3 63,0 62,3
65,5 65,8 65,5 64,8 64,5
PREDICTED NOISE LEVELS wlth NO barrier(dBA)
NE' ENE ~ EsE "SE
73,0 71,9 70,5 69,3 68,0
73,2 73.3 71,8 70,3 68,9
75,3 74.1 72,6 71,3 69,7
75,3 74,7 73,3 72.0 70,3
73,5 73.8 73,5 72,8 71,5
8 DOOR
60,5 56.8
59,4 55,8
61,1 57,8
61,7 58,1
63,4 60,0
TABLE OFBARRIERBENEFITS (dBA)
N NE ENE E ESE SE
9 8 8 8 7 6
11 8 11 9 8 6
11 1t 10 t0 8 8
11 10 lO 10 9 8
6 8 8 8 6 7
8 DOOR
67,5 64,8
68.4 65.8
69,1 66,8
69,7 67,1
70.4 67.0
DOOR
8
I0
9
9
7
TABLE
NE
11.2
11.2
1t,4
11,3
11,0
OF EFFECTIVE BARRIER HEIGHTS (feet)
EN~ E ESE SE
11,2 11.2 tl,2 1t.2
11,5 11.5 11,4 10,9
11,4 11.4 11.4 11,4
11,4 11.4 11,4 11.3
10,9 11.0 10.9 11.0
8 DOOR
11,3 10.6
11,6 11.0
11,5 10.8
11.5 10,8
11.1 9.9
11/18/98-8:33 AM-Barr6al¢,xls
DEC 10 1998 12:03 FR DAVID BRASLAU ASSOC 6i2 331 45?2 TO 9375739 P.88/08
BERM WALL-2ND
LOCATION
PREDICTED.. NOISE LEVEL,$ with barrier (dBA) ......
NE ENE E ESE SE
2503 65,9
2499 67,0
2495 67,5
2491 67,5
2483 65.9
67,0 65.9 . 64,5 63,3 63.0
67.2 67,3 65,8 64.3 62,9
69,3 68,1 66,6 65,3 63.7
69,3 68,7 67,3 66,0 64,3
67,5 67,8 67,5 66,8 65.5
S DOOR
62,5 55.8
62.4 55,8
63,1 56.8
63,7 57.1
64,4 58,0
LOCATION '" N
250~" 71.9
2499 73.0
2495 73.5
2491 73,5
2483 71,9
PREDICTED NOISE LEVELS with NO barrier (dBA),,
NE ENE E ESE
73,0 71.9 70,5 69,3
73.2 73,3 71,8 70,3
75,3 74,1 72,6 71,3
75,3 74,7 73,3 72,0
73.5 73-8 73.5 72.8
SE $ DOOR
68.0 67,5 60,8
68,9 68.4 6t,8
69,7 69.1 62,8
70.3 69,7 63,1
71,5 70.4 63.0
LOCATION N
2503 6
2499 6
2495 6
2491 6
2483 6
TABLE ,OF BARRIER,. BENEFITS (dBA)
NE ENE E ESE
6 6 6 6
6 6 6 6
6 6 6 6
6 6 6 6
6 6 6 6
SE S DOOR
5 5 5
6 6 6
6 6 6
6 6 6
6 6 5
TABLE
LOCATION N NE
2503 4,3 4.5
2499 3.9 4,6
2495 3.9 4.3
2491 4,0 4,4
2483 4.8 5,0
OF EFFECTIVE BARRIER H, EIGHTS (re ,e,,t,)
ENE E ESE
4.5 4,6 4.7
4,0 4.1 4,1
4,2 4,2 4.3
4.3 4,3 4,3
5.1 5,0 5,2
SE $ DOOR
4,6 4.4 3.4
5,2 3,8 3.3
4,3 4.0 3.3
4,3 4,0 3.3
5,0 4,7 3.6
t tll 8/98-8:34 AM-Barrcalc.xl$