RECOMMENDATION: THAT Council: Expansion Joint Noise …

PITT MEADOWS

REPORT INFORMATION REPORT TO COUNCIL

DATE: October 27, 2016 FlI.E: 11-5240-01/16FROM: Department of Engineering and Operations

SUBJECT: Golden Ears Bridge — Expansion Joint Noise Update

RECOMMENDATION: THAT Council:

A. Receive the report dated October 27, 2016 from the Director of Engineering and Operationsregarding the Golden Ears Bridge — Expansion Joint Noise Update for information; OR

B. Other.

CHIEF ADMINISTRATIVE OFFICER COMMENT/RECOMMENDATION:

(7/)Staff time on this file has become disproportionately high when compared to the minimal value andquality of information received from Translink.

/PURPOSE: To provide Council the information received from TransLink on September 8, 2016 withrespect to the July 19, 2016 Council motion directing staff to request information from TransLinkregarding sound measurement readings. In particular the date, time and weather conditions for allreadings and further description of the term “rigorous procedures” used to maintain the expansion jointnoise mitigation material.

BACKGROUND:

On May 19, 2015 Council motioned for staff to invite TransLink to attend a Council in Committeemeeting to share the test results and standards and maintenance with respect to Golden Ears expansionnoise. TransLink responded to this request with a letter included in the staff summary report(Attachment B.)

On September 15, 2015 Council motioned that consideration to send a letter under the Mayor’ssignature to TransLink requesting maintenance reports with respect to noise mitigation inserts bedeferred until such times as the response from TransLink is discussed at a future Council in Committeemeeting.

Following receipt of the letter from TransLink, City staff followed up with TransLink staff requestingcopies of any maintenance activity records. E-mail communication in October 2015 concluded thatTransLink does not have detailed maintenance records.

On January 30, 2016 staff contacted TransLink requesting the name of the company that performed themaintenance work for the Golden Ears Bridge expansion joints and contact information for someone atthe company.

On February 2, 2016 Susan Chu, TransLink Project Manager, Infrastructure and Network Management,contacted staff to confirm Council’s request and offered to make the request on the City’s behalf. On

#138461v1- 85 -

PITT MEADOWS

February 10, 2016 a letter was received from Ms. Chu with the requested information. Council receivedthis information on March 1, 2016 and requested additional information regarding 2012 soundmeasurement readings and to note to TransLink that the sound deadening fencing does not appear tohave been installed on raised berms as referenced in their letter dated February 10, 2016.

On March 2, 2016 staff contacted TransLink requesting the sound measurement readings from 2012 andnoted to TransLink that that the sound deadening fencing does not appear to have been installed onraised berms as referenced in their letter dated February 10, 2016.

On May 9, 2016 a letter was received from Susan Chu, TransLink Project Manager, Infrastructure andNetwork Management, with the requested information.

Attached to this letter was a March 26, 2013 peer review prepared by Wakefeild Acoustics Ltd , for HGCEngineering and TransLink (Attachment D). This report contains the testing data prior to 2013 asrequested by Council.

The second attachment to the May 9, 2016 letter, included a July 11, 2013 Expansion Joint Sound Studyprepared by HGC Engineering for TransLink. This report has previously been received by Council.

The third attachment to the May 9, 2016 letter included an April 27, 2015 expansion joint noise follow-up report prepared by Wakefield Acoustics for TransLink. This report has also been previously receivedby Council.

Additionally, in Ms. Chu’s response letter, she stated that in 2012, a taller sound wall was constructed.This new sound wall of 4.5 meters in height, sits 1.5 meters taller than the previous 3.0 meter soundwall. Ms. Chu also confirmed that the taller sound wall has the same extent and road setbacks as theprevious sound wall.

NEW COMMUNICATION:

On September 8, 2016, the following information was received from Susan Chu, TransLink ProjectManager, Infrastructure and Network Management, with the requested information (Attachment A).

Council’s follow up question 1:

Is there any data available on the exact time of day the sound measurements took place and what theweather conditions were during the readings?

TransLink response 1:

As per the Golden Ears Bridge Modular Expansion Joint Noise-Follow-up Noise Measurementreport (Wakefield Acoustics, April2015), the sound measurements were taken at night time toisolate the residual “croaksfrom the background noise levels. At Site 2, near the WildwoodCrescent residences, it was confirmed that the measurements were taken between 2:39 AM and3:06 AM, the quietest portion of the night, on April 9, 2015. The weather condition on the nightof April 9, 2015 is noted in Table 1, which is provided on page 2 of the report produced byWakefield Acoustics.

#138461v1- 86 -

Puff MEADOWS


There was mention in Sanny Zein’s letter dated July 17, 2015 about “rigorous procedures” to maintainthe expansion joint noise mitigation material. Council has requested what activities are included. (ie.further information on how and when inspections occur and maintenance is performed)


A summary of maintenance activities for the expansion joints were provided to the City of PittMeadows in a TransLink letter dated February 11, 2016. The Bridge is patrolled daily andmaintenance on the bridge expansion joints takes place on an as-needed basis to replacedislodged filler material. As indicated in the letteG temporary repairs are typically conducted inthe winter:, between November and March, when weather conditions do not allow for long-termrepairs. In the summer months, the temporary repairs are removed and replaced withpermanentfiller material.


Is TransLink able to provide a schedule for sound measurements? For example, does TransLink schedulewinter and summer testing on a set schedule?


TransLink has taken reasonable measures to mitigate noise concerns. To ensure lastingperformance of the filler material, TransLink will continue to periodically take soundmeasurements emittedfrom the expansion jOints. As indicated in the Golden Ears BridgeModular Expansion Joint Noise-Follow-up Noise Measurement report (Wakefield Acoustics, April2015), there has been no loss in noise reduction performance of the geotextile/neoprene sealtreatments since the treatment was first installed.

We would be pleased to continue providing maintenance records and results offuture noisesurveys. At this time, we are not planning additional noise mitigation improvements as the fillermaterial continues to successfully reduce noise levels experienced by the residences.

In addition to the correspondence above, staff also prepared a summary of all noise measurementsprovided in the correspondence received thus far for Council’s review:

#138461v1- 87 -

Puff MEADOWS

April 27, 2015

Wakefield Acoustics

Follow-up Noise Measurement

Location Start Time Weather Average Sound(DD/MM/YY —24 hour)

7m North of NAV Joint 09/04/15 13:38 — 13:49, Dry conditions prevailed 76.6 dB(West) 14:25 — 15:31 with clear skies,

negligible wind anddaytime highs of 15 C.

7m North of M6 Joint 09/04/15 13:57 — 14:24 Dry conditions prevailed 78.3 dB(West) with clear skies,

negligible wind anddaytime highs of 15 C.

19880 Wildwood Cr 09/04/15 02:39 — 3:06 Dry conditions prevailed 47.4 dBA*

with clear skies,negligible wind andnighttime lows of 4 C.

*Corrected for background noise

July 11, 2013

HCG Engineering

Sound Study


7m North of NAV Joint 01/03/13 Morning Light rain, measures 79.3 dB(West)** taken to minimize

equipment exposure tomoisture, backgroundnoise due to rainnegligible.

7m North of M6 Joint 01/03/13 Morning Light rain, measures 81.1 dB(West)** taken to minimize

equipment exposure tomoisture, backgroundnoise due to rainnegligible.

** Measured at Om and 15m north of joint; linearly interpolated to obtain 7m.

#138461v1- 88 -

Puff MEADOWS

March 26, 2013

Wakefield Acoustics

Noise Control Peer Review

After Noise Control Measures

Location Start Time Weather Average Sound(DD/MM/YY—Z4hour)

7m North of NAV Joint 16/06/11 Not noted 79.9 dB(West)19880 Wildwood Cr 30/08/11 02:02 — 02:16 Not noted 46.3 dB

Before Noise Control Measures

Location Start Time Weather Average Sound(DD/MM/VY—24hour)

7m North of NAV Joint 20/06/11 Not noted 90.2 dB(West)19880 Wildwood Cr 03/03/10 Not noted 58.0 dB

November, 2010

BKL Consultants

Post-Construction Noise Measurements


19880 Wildwood Cr 27/05/10 — 28/05/10 Not noted 54.3 dBA

August 19, 2009

BKL Consultants

Post Construction Noise Measurements


19880 Wildwood Cr 30/07/09 14:35 Favourable conditions; 50.2 dBAsunny with temperaturesof 37 C and minimalwind.

#138461v1- 89 -

PITT MEADOWS

April 23, 2007

Wakefield Acoustics

Bonson’s Landing Preliminary Noise Impact


19880 Wildwood Cr 17/09/02 Not noted 50.3 dBA

RELEVANT POLICY: none identified by staff.

STRATEGIC ALIGNMENT: Provide and encourage a community conductive to a safe and healthy living.

OTHER CONSIDERATIONS: none identified by staff.

Submitted by: F. Smith, Director of Engineering and Operations

Approved by: M. Roberts, CAD

ATfACHMENT(S):

A. Letter from Susan Chu, Project Manager, Infrastructure and Network Manager, TransLink, datedSeptember 8, 2016.

B. Staff Summary Report (dated: July 11, 2016)

#138461v1- 90 -

f”’ TransLink

T RANS/’i:iiKCanadaTel 778-375-7500wvvw.translink.ca

South Coast British ColumbiaTransportation Authority

September 8, 2016

Mr. Forrest Smith, P.Eng.Director of Engineering and OperationsCity of Pitt Meadows,12007 Harris Road,Pitt Meadows, BC, V3Y 2B5

Dear Mr. Smith,

RE: Request for Information on the Golden Ears Bridge Expansion Joints

Thank you for the opportunity to provide information regarding noise management activitiesrelated to the expansion joints on the Golden Ears Bridge.

As per the Golden Ears Bridge Modular Expansion Joint Noise-Follow-up Noise Measurementreport (Wakefield Acoustics, April 2015), the sound measurements were taken at night time toisolate the residual “croaks” from the background noise levels. At Site 2, near the WildwoodCrescent residences, it was confirmed that the measurements were taken between 2:39 AM and3:06 AM, the quietest portion of the night, on April 9, 2015. The weather condition on the night

of April 9, 2015 is noted in Table 1, which is provided on page 2 of the report produced byWakefield Acoustics.

A summary of maintenance activities for the expansion joints were provided to the City of PittMeadows in a TransLink letter dated February 11, 2016. The Bridge is patrolled daily andmaintenance on the bridge expansion joints takes place on an as-needed basis to replacedislodged filler material. As indicated in the letter, temporary repairs are typically conducted in

the winter, between November and March, when weather conditions do not allow for long-termrepairs. In the summer months, the temporary repairs are removed and replaced withpermanent filler material.

TransLink has taken reasonable measures to mitigate noise concerns. To ensure lastingperformance of the filler material, TransLink will continue to periodically take soundmeasurements emitted from the expansion joints. As indicated in the Golden Ears Bridge

Modular Expansion Joint Noise-Follow-up Noise Measurement report (Wakefield Acoustics, April

2015), there has been no loss in noise reduction performance of the geotextile/neoprene sealtreatments since the treatment was first installed.

/..2

ATTACHMENT A

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Mr. Forrest SmithCity of Pitt MeadowsRE: Request for Information on the Golden Ears Bridge Expansion JointsSeptember 8, 2016 Page 2

We would be pleased to Continue providing maintenance records and results of future noisesurveys. At this time, we are not planning additional noise mitigation improvements as the fillermaterial continues to successfully reduce noise levels experienced by the residences.

Thank you again for this opportunity to provide an update.

Regar,

Susan Chu, P.EngProject Manager, Infrastructure Program Management

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PflT MEADOWS

REPORT INFORMATION REPORT TO COUNCIL

DATE: July 11, 2016 FILE: 11-5240-01/16FROM: Engineering and Operations Department

SUBJECT: Golden Ears Bridge — Expansion Joint Noise Update

RECOMMENDATION: THAT Council:

A. Receive the report dated July 11, 2016 from the Director of Engineering and Operations regardingthe Golden Ears Bridge — Expansion Joint Noise Update for information; OR

B. Other.

CHIEF ADMINISTRATIVE OFFICER COMMENT/RECOMMENDATION:

PURPOSE: To provide Council the information received from TransLink on May 9, 2016 with respect tothe March 1, 2016 Council motion directing staff to request information from TransLink regarding 2012sound measurement readings.

BACKGROUND: On May 19, 2015 Council motioned for staff to invite TransLink to attend a Council inCommittee meeting to share the test results and standards and maintenance with respect to GoldenEars expansion noise. TransLink responded to this request with a letter included as Attachment A.

On September 15, 2015 Council motioned that consideration to send a letter under the Mayor’ssignature to TransLink requesting maintenance reports with respect to noise mitigation inserts bedeferred until such times as the response from TransLink is discussed at a future Council in Committeemeeting.

Following receipt of the letter from TransLink, City staff followed up with TransLink staff requestingcopies of any maintenance activity records. E-mail communication in October 2015 concluded thatTransLink does not have detailed maintenance records.

On January 30, 2016 staff contacted TransLink requesting the name of the company that performed themaintenance work for the Golden Ears Bridge expansion joints and contact information for someone atthe company.

On February 2, 2016 Susan Chu, TransLink Project Manager, Infrastructure and Network Management,contacted staff to confirm Council’s request and offered to make the request on the City’s behalf. OnFebruary 10, 2016 a letter was received from Ms. Chu with the requested information. (Attachment B)Council received this information on March 1, 2016 and requested additional information regarding2012 sound measurement readings and to note to TransLink that the sound deadening fencing does notappear to have been installed on raised berms as referenced in their letter dated February 10, 2016.

I

66 #136859v1

ATTACHMENT B

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PlU MEADOWS

NEW COMMUNICATION: On March 2, 2016 staff contacted TransLink requesting the soundmeasurement readings from 2012 and noted to TransLink that that the sound deadening fencing doesnot appear to have been installed on raised berms as referenced in their letter dated February 10, 2016.

On May 9, 2016 a letter was received from Susan Chu, TransLink Project Manager, Infrastructure andNetwork Management, with the requested information (Attachment C).

Attached to this letter was a March 26, 2013 peer review prepared by Wakefeild Acoustics Ltd, for HGCEngineering and TransLink (Attachment D). This report contains the testing data prior to 2013 asrequested by Council.

The second attachment to the May 9, 2016 letter, included a July 11, 2013 Expansion Joint Sound Studyprepared by HGC Engineering for TransLink (Attachment E). This report has previously been received byCouncil.

The third attachment to the May 9, 2016 letter induded an April 27, 2015 expansion joint noise follow-up report prepared by Wakefield Acoustics for TransLink (Attachment F). This report has also beenpreviously received by Council.

Additionally, in Ms. Chu’s response letter, she stated that in 2012, a taller sound wall was constructed.This new sound wall of 4.5 meters in height, sits 1.5 meters taller than the previous 3.0 meter soundwall. Ms. Chu also confirmed that the taller sound wall has the same extent and road setbacks as theprevious sound wall.

RELEVANT POLICY: none identified by staff.

STRATEGIC ALIGNMENT: Provide and encourage a community conductive to a safe and healthy living.

OTHER CONSIDERATIONS: If Council would like to take any further action.

Submitted by: F. Smith, Director of Engineering and OperationsApproved by: M. Roberts, CAO

ArrACHMENT(S):

A. Letter from Sany R. Zein, Director, Infrastructure and Network Manager, TransLink, dated July17, 2015.

B. Letter from Susan Chu, Project Manager, Infrastructure and Network Manager, TransLink, datedFebruary 10, 2016.

C. Letter from Susan Chu, Project Manager, Infrastructure and Network Manager, TransLink, datedMay 9, 2016.

D. Golden Ears Bridge Expansion Joint Noise Control Peer Review, prepared by: WakefieldAcoustics, dated March 26, 2013.

E. Golden Ears Bridge Expansion Joint Sound Study, prepared by: HGC Engineering, dated July 11,2013..

F. Golden Ears Bridge Modular Expansion Joint Noise — Follow-up Noise Measurement, preparedby: Wakefield Acoustics, dated April 27, 2015.

67 #136859v1

- 94 -

ATTACHMENT ATransUnk

TRANS/1111KCanadaTel 778-375-7500www.transiink.ca

South Coast British ColumbIaTransportation Authority

July 17,2015

Ms. Kate Zanon

Director of Operations and Development Services

City of Pitt Meadows,

12007 Harris Road, Pitt Meadows, BC, V3Y 285

Dear Ms. Zanon:

RE: Golden Ears Bridge Update

Thank you for the opportunity to provide an update on the Golden Ears Bridge and specificallynoise management activities related to the expansion joints. We understand thatthis issue wasdiscussed at the May 19th, 2015 CouncIl Meeting. -

We are pleased to report that the residents and businesses served by the Bridge are using thecrossing in increasing numbers. The community has embraced the presence of the bridge, asresidents now recognize its importance in providing reliable and efficient access throughout theyear. There are approximately 12 million crossings per year on the Golden Ears Bridge, andmany of the users are Pitt Meadows residents, customers and bus(nesses owners. There hasbeen consistent gràwth in bridge usage over the past six years, and in 2015 to date, year-over-year growth Is in the range of 8%.

The introduction of bus service across the bridge has Improved transit connections to and fromPitt Meadows, offering travelers a more sustainable mode choice. Meanwhile, economicdevelopment has benefited from the presence of the bridge, including locations such as theGolden Ears Business Park on Airport Way. The pedestrian and cycling facilities provided on thebridge have been well received by the large numbers of regular users, plus the organized groupsusing the bridge as a focus of theirannual events.

68- 95 -

Ongoing monitoring of Golden Ears Bridge Expansion Joint Noise In Pitt MeadowsPge2

As you know, Transunk has been actively managing the expansion joint noise issue since the

Bridge was opened to the public in June 2009. The bridge has always met, and continues to

meet, all relevant Industry standards for noise emissions.

In consultation with local and national independent experts In noise mitigation we installed an

expansion joint filler solution between 2011 and 2012 to further help with noise mitigation. The

solution proved effective and resulted in a reduction in the noise level of 15% at the bridge joint

location, and 18% close to the residences on Wildwood Crescent S. This is the equivalent of the

noise reduction achieved by inserting Industrial earplugs when standing next to the expansion

joint.

We have rigorous procedures to maintain the expansion joint noise mitigation material. Our

latest measurements, completed in April 2015, show a slight Improvement in sound reduction

from the previous readings taken In 2012, and show that the solution Is working as intended.

We are happy to share with you our latest technical reports related to noise management.

Please contact Bob Moore, Project Manager — Bridge Operations, for the latest reports.

Translink will continue to maintain the expansion joint filler material, and measure the noise

emitted to ensure continued performance. We are not considering or planning any other noise

mitigation actions.

Thank you again ftr this opportunity to provide an update.

Yours truly,

Sany R. Zein, M. Eng., P.Eng.

Director, Infrastructure and Network Management

69- 96 -

flCHMENT B

1ransLlnk

TRAI15/ LINKTel TTB.3T5J500

www.tsanslink.ca


February 10,2016

Ms. Kate ZanoñDirector of Operations and Development ServicesCity of Pitt Meadows12007 Harris Road, Pitt Meadows, BC, V3Y 2B5

Dear Ms. Zanon:

RE: Council motion requesting Golden Ears Bridge maintenance records

Thank you for your email informing TransLink of the Council motion ofJanuary 19,2016requesting maintenance records and the maintenance schedule for the Golden Ears Bridge,specifically related to bridge expansion joint maintenance activities.

TransLink has been actively managing the expansion joint noise issue since the Bridge wasopened to the public In 2009. It Is important to note that the bridge has always met, andcontinues to meet, all relevant industry standards for noise emissions.

In consultation with local and national Independent experts in noise mitigation Translinkactively responded to noise concerns raised by some nearby residents by installing an expansionjoint filler solution between 2011 and 2012 to further help with noise mitigation.

This effective solution reduced the noise level by 15% at the bridge joint location, and 18% closeto the residences on Wildwood Crescent. This is the equivalent of the noise reduction achievedby inserting Industrial earpiugs when standing next to the expansion joint.

Additionally, 15-foot high sound deadening fencing was installed on raised berms and speedand noise reduction measures, including larger speed limit signs, use of engine brake signs,additional road markings, and LED speed limit signs were introduced.

Sound measurements, completed in April 2015, show additional improvements in soundreduction from the previous readings taken in 2012, demonstrating that these changes areworking as intended.

The bridge is patrolled every 24 hours and maintenance on the bridge expansion joints takesplace on an as-needed basis. Translink is pleased to provide a log ofmaintenance activities forthe expansion joints (attached).

70- 97 -

Translink will continue to maintain the expansion joint filler material, and measure the noiseemitted to ensure continued performance. We are not considering or planning any other noisemitigation actions.

Chu,P.EngProject Manager, Infrastructure & Network Management

Attachment Log of maintenance activities for Golden Ears Bridge expansion joints

2/2

Yours I

71- 98 -

0

TransLink400-287 Nelson’s CoudTRANI/INk New Westminster, BC V3L 0E7CanaTel 778.375.75D0

www.tjansliok.ca


Lo of maintenance activities for Golden Ears Bricke expansion joints

Date Type of Repair to the Quantity of Joints RepairedExpanslonlolnts on the (m)Golden Ears Bridge

February 25, 2013 Temporary repairs* and 76.5

Installation of missing joint

material

February 26, 2013 Temporary repairs and 42.2

Installation of missingjoint

material

February 27, 2013 Temporary repairs and 6.2

Installation of missingjoint

material

July 11, 2013 Permanent repairs** and 31.5installation of mlssing joint

material

July 12,2013 Permanent repairs and 105installation of missing joint

material

July 11, 2013 Permanent repairs and 31.5

installation of missing jQint

materialJuly 15, 2013 Permanent repairs and 43.8

installation of missing joint

material

July 16, 2013 Permanent repairs and 30

installation of missing joint

material

July 17, 2013 •Permanent repairs and 49.4installation of missing joint

material

August 23, 2013 Permanent repairs and 5Installation of missingjoint

material

72- 99 -

Lo of maintenance activities for Golden Ears Bridge expansion joints (continued)

December 23, 2013 Minor repairs Minor repairsFebruary26,2014 . Mfñor repairs Minor repairsMarch 2, 214.. Minor repairs Minor repairsApril11, 2014 Minor repairs Minor repairsMay 6, 2014 Minor repairs Minor repairsJuly 31, 2014 Permanent repairs and 225

installation of missing joint‘

. materialAugust 5, 2014 Permanent repairs and 23

. installation of missingjoint. material

August 6, 2014 Permanent repairs and 39V Installation of missing joint

materialMarch 13, 2015 Permanent repairs and 45.4

installation of missingjointmaterial

March 16, 2015 Permanent repairs and 10.5installation of missing joint

. material V

March 17, 2015 Permanent repairs and 33.7installation of missingjointmaterial -

November 2, 2015 Permanent repairs and 18.5installation of missingjoint

. materialNovember 3, 2015 Permanent repairs and 15

. installation of missingjoint

V_______________________

materialNovember 9, 2015 Permanent repairs and 10.5

V installation of missing jointmaterial

Temporary repairs are defined as being performed in the winter, when temperatures do notallow for long-term repairs to be made.

Permanent repairs are defined as performed outside of the winter months to repair theexpansion joint for the longer-term.

73- 100 -

e A1TACHMENT C* TransLink

TRANS/iiKCanadaTel 778-375-7500www.translink.a

South Coast British Columbia

May 9, 2016Transportation Authority

MSL Kate ZanonDirector of Operations nd Development ServicesCity of Pitt Meadows,12007 1-la rris Road, -

Pitt Meadows, BC, V3Y 2B5

Dear: Ms. Zanon

RE: Request for Additional Information on Golden Ears Bridge Expansion JoInts andSound Wall

Thank you for the opportunity to provide information regarding noise managementactivities related to the expansion joints on the Golden Ears Bridge.

As per your request, please find attached reports that provide information on the soundreadings taken from 2011 and from 2010, before the filler material was installed at theexpansion joints. We have also attached the Gokien Ears Bridge Expansion JointSoundStudy (KGC EngIneering, 2013), which concludes thatTranslink has undertaken a reasonableapproach to reduce noise associated with the expansion joints. In addition, please also findattached a fbllow-up noise report that was undertaken in April 2015 to verify the material’songoing effectiveness. Based on the April 2015 noise readings, the filler material contTnuesto successfully reduce noise levels by up to 15% and 18% at the bridge joint location andnear the Wildwood Crescent residences respectively.

Since the Bridge was opened in 2009, TransLink has been active!y managing the expansionjoint noise Issues. In response to concerns expressed by residents living in the area of theBridge, TransLink met with Southern Pitt Meadows Residents’ Association; conducted anumber of studies, laboratory and field tests; and, in 2011, installed the joint filler materialto help with noise mitigation. In 2012, to further reduce noise, a higher sound wall wasconstructed. The new sound wall has the same extents and road setback as the old soundwall, but is 4.5 metres above grade (1.5 metres higher than the old 3,0 metre sound wall).TransLink also had discussions with Ridge Meadows regarding increased speedenforcement.

74- 101 -

May9, 2016

Request forAdditlonal information on Golden Ears Bridge Expansion Joints and Sound Wall

Since becoming aware of noise concerns, more than $1 million has been spent to implementnoise mitigation. TransLink will continue to maintain the expansion joint filler material andconduct noise measurements to ensure continued performance. We would be pleased tocontinue providing maintenance records and results of future noise surveys. Kowever, atthis time, we are not contemplating or planning additional noise mitigation improvements.

Thank you again for this opportunity to provide an update.

Regards,

Susan Chu, P.EngProject Manager, Infrastructure & Network Management

Attachment:1) 13-M252-1 Golden Ears Brlde Expansion Joint NaIs’e Control Peer Review by Wakefield Acoustics Ltd.

(March 26, 2013)

2) Golden Ears Bridge Expansion JointSocind SWiby HGC EngIneering (June 21, 2013)

3) Golden Ears Srldge ModLlIar Expansion Joint Noise— Follow-Up Measurement by Wakefield AcousticsLtd. (Ap1l 27,2015)

..

75- 102 -

ATrACHMENT D

13-M252-1 Golden Ears Bridge Expansion Joint Noise Control

Peer Review

Prepared for: HGC Engineering and Translink

Prepared by: Wakefield Acoustics Ltd.

Date: March 26, 2013

76- 103 -

13-M252-1 Golden Ears Bridge Expansion Joint Noise Control Peer Review

Description:

Control Site (Sidewalk):

The control site measurements for the passage of general traffic over the North Approach Viaductjoint (NAV) are presented on page 3. Measurements at the NAV of vehicles in thesouthbound middle lane “after” noise control, were taken on June 16, 2011. Measurementsat the NAV northbound middle lane “before” noise control, were taken on June 20, 2011.In both cases, the microphone was located on the sidewalk 7 meters behindthe vehicles passing over the joint. In this case the offset of the control site monitoringlocation is defined to be -7 meters. (Due to joint emission directionality, noise at positiveoffset locations, i.e. infront of vehicles, is suppressed.)

The difference in the averages of30 general traffic tire/NA Vjoint interaction noise levelssummed over the one-third octave bands centered on 500, 680, 800 and 1000 Hzwas LmaxF 10.3 dB.

One-third octave band spectra of various vehicles passing over the NAV joint “before” noise control,are provided on page 4. A typical MaxSpec of a vehicle passing over the NAV joint “after” noisecontrol, is provided on page 5. There, it is evident that tonal content in the 500 to 1000Hz range is relatively minor.

Residential Site (19880 Wildwood Crescent S):

Tire/joint interaction noise events measured at 19880 Wildwood Crescent S are presentedon page 6. Noise events at the residence were logged on March 3, 2010 “before” the noisecontrol was implemented and August 30, 2011 after. Events from NAV and M6 are included.

Tire/joint interaction noise emissions from all southbound lanes propagate to the microphone at theresidence roughly 585 meters to the north. Since the microphone was behind the vehicles, the offsetis taken to be -585 meters. Noise emissions from the northbound lanes (microphone offset+585 meters) are suppressed due to the directionality of the noise source.

The difference in the averages of 30 general traffic tire/NAV&M6-joint interaction noise levelswas LAFmax 11.7 dB. However due to the temperature variation of the bridge deck from March toAugust, and its anticipated effects on the width of the joint gaps, a 3 or 4 dBA seasonalcorrection should be applied.

The benefit at 19880 Wildwood Crescent S would then be in the range LAFmax Z 7 to & 7dB.

The extact times of the tire/joint interaction noise events “after” noise control, are provided onpage 7. These may be confirmed using the B&K Type 2250 data file with audio track availableon request.

2

Wakefield Acoustics Ltd.

77- 104 -

13-M252-1 Golden Ears Budge Expansion Joint Noise Control, Joint-Side (Sidewalk) MeasurementsSummation of Maximum Noise Levels in Contiguous One-Third Octave BandsCentered on 500, 630, 800 and 1000 Hz

20-Jun-il iJun-liJoh North Approach Viaduct North Approach Viaduct

North Bound Middle South Bound MiddleGeneral General

Joint-Side (Sidewalk) Joint-Side (Sidewalk)

ueveisinaji

- 7 meters - 7 meters

None Geotextile and Neoprene SealsLarson Davis RTA Model 2800 Larson Davis RTA Model 2800

98.8 82.587.9 82.289.4 82.084.5 83.390.6 88.190.8 81.883.8 83.196.9 84.388.9 84.587.0 75.293.5 78.3

85.5 80.091.1 81.7

88.4 84.482.1 74.6

83.1 81.7

81.2 79.677.391.8

91.5

________________________

72.189.7 80.397.3 77.387.9 76.6

90.9 75.189.5 75.9100.7 79.794.5 80.591.7 77.392.7 79.6

98.6 78.990.2 79.9

10.3

5.0 I 3.5

85.9 80.2

3

78WakefieldAcoustics Ltd.

- 105 -

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13-M252-l Golden Ears Bridge Expansion Joint Noise Control Wildwood Community MonitoringMaximum Broadband Levels of Tire/NAY-Joint Interaction Noise Events Measured in dBAFast Response

WakefieldAcoustics Ltd.

03-Mar-10 30-Aug-IlNorth Approach ViaductlM6 North Approach ViaductlM6

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81- 108 -

13-M252-1 Golden Ears Bridge Expansion Joint Noise Control - Wildwood Community MeasurementsTime of Day (TOD) of Measurement of Maximum Broadband Noise Levels of Tire/NAY-Joint InteractionNoise Events Measured in dBA Fast Response

I Date: 30-Aug-li

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7

Wakefield Acoustics Ltd.

82- 109 -

ATIACHMENT EW

‘4i A ‘44HGC ENGINEERING

Howe Gastmeler Chapnlk Limited2000 Argentia Road, Plaza One, Suite 203

Mlssissauga, Ontario, Canada L5N 1 P7t: 905.826.4044

Golden Ears Bridge Expansion Joint

Sound Study

Prepared for:

TransLink

and

Brian Howe, MEng, MBA, PEng

July 11,2013

ACOUSTICS NOiSE VIBRATION www.hgcengineering.com

Prepared by:

Nick McCabe, MESc, PEng

83- 110 -

Table of Contents

1 INTRODUCTION .1

2 DOCUMENTATION REVIEWED 2

2.1 TransLink Communications 2

2.2 Wakefield Acoustics Reports 4

2.3 University of British Columbia Acoustic Testing 6

2.4 Mageba Documentation 6

2.5 Research Papers 7

3 SOUND MEASUREMENTS AND ANALYSIS 9

3.1 Sound Measurements on Bridge Deck 9

3.2 Assessment of Expansion Joint Filler Effectiveness 11

3.3 Technical Review of Selected Mitigation Approach 14

4 CONCLUSIONS 18

Figure 1. Sample of Sound Levels Monitored 15 m North of Expansion Joint M6, March 1,2013.

Figure 2. Frequency Spectrum of 25 Vehicles Passing Over Expansion Joint M6 (measured15m to the North), March 1, 2013.

Figure 3. Frequency Spectrum of 30 Vehicles Passing Over Expansion Joint M6 (measured inline with joint), March 1, 2013.

Figure 4. Frequency Spectrum of 32 Vehicles Passing Over Southbound North ApproachViaduct Joint (measured 15m to the north), March 1, 2013.

FigureS. Frequency Spectrum of 31 Vehicles Passing Over Southbound North ApproachViaduct Joint (measured in line with joint), March 1, 2013.

Figure 6: Comparison of Frequency Spectra of Average Sound Levels Measured at ExpansionJoints by IIGC Engineering (after treatment) and Wakefield Acoustics (before treatment).

Figure 7. Peak Frequency of Fast Fourier Transform of Sound Level Measured for 13 VehiclesPassing Over M6 Joint, March 1, 2013.

Appendix A: Reference Materials (Under separate cover)

ACOUSTICS NOISE VIBRATION www.hgcengineering.com

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TransLink Page 1Golden Ears Bridge Expansion Joint Sound Study June 21, 2013

I INTRODUCTION

HGC Engineering was retained by TransLink to review expansion joint noise mitigation work

undertaken on the Golden Ears Bridge, and to provide an opinion on the effectiveness of the

measures which have been introduced.

Residents of the southeastern portion of the City of Pitt Meadows have complained about an

intermittent sound, often referred to as “croaking”, produced by vehicles crossing over expansion

joints on the Golden Ears Bridge. The residents have identified two joints on the southbound lanes as

causing the most obtrusive sound: the North Approach Viaduct -joint (the NAV joint) and at the main

north stay joint (the M6 joint). Since the time the complaints first arose in 2009, TransLink has been

investigating the mechanism causing the noise, and has given consideration to mitigating its impact.

In August of 2012, after testing a variety of materials, a geotextile material covered by neoprene

strips was installed in between the lamella beams of the modular expansion joints as the selected

noise mitigation measure.

The purpose of the review by HGC Engineering is to determine, from a technical perspective, if the

mitigation which was selected and installed is effective and founded on accepted acoustical

engineering principals, or if sinus plates or an alternate joint material would be preferable.

To complete our work, we have reviewed and considered the following:

• Correspondence between TransLink and Mageba, the manufacturer of the expansion joints,which had earlier been collected under a Freedom of Information request.

• Documents prepared by Wakefield Acoustics Ltd., the acoustical consultant retained byTransLink to investigate the noise generated by the passage of vehicles over the expansionjoints and its impact at the nearby Pitt Meadows community, and to develop mitigationstrategies.

• The results of sound absorption testing undertaken by the Acoustics and Noise Research Groupat the University of British Columbia.

• Product literature published by Mageba.

• Research papers prepared on the subject of noise from expansion joints.

ACOUSTECS WOtSE VBRATtON www.hgcenglneering.com

85- 112 -

TransLrnk Page 2Golden Ears Bridge Expansion Joint Sound Study Draft July 11, 2013

In addition to the review, HOC Engineering met with representatives from TransLink, Wakefield

Acoustics and the Southern Pitt Meadows Residents’ Association on February 28, 2013, and

inspected the bridge and conducted acoustic measurements on March 1, 2013

The results or our review are presented in the following sections.

2 DOCUMENTATION REVIEWED

2.1 TransLink Communications

In 2010, a Freedom of Information request was made to obtain records of communications between

TransLink and Mageba concerning the expansion joints on the Golden Ears Bridge. TransLink

complied and produced a 324 page document dated July 8, 2010 containing this information.

Although the document contains a large number of email messages, much of the information is

redundant or of no relevance to the noise issue. The following are the key points related to the joint

noise which emerge from the document:

• On September 2, 2009, TransLink first contacts Mageba indicating that homeowners haveexpressed significant concerns about noise from the North Approach Viaduct expansion joint.TransLink requests information concerning the technical feasibility, cost, lead time, andeffectiveness of retrofitting the expansion joint with sinus plates.

• Mageba responds on September 3, 2009, indicating that sinus plates are effective at reducingnoise “by creating a surface which provides continuous support to vehicle wheels and whicheliminates straight perpendicular edges for the wheel to impact against”. They point out thatretrofitting the joint with sinus plates is not straightforward and raises a number of factors thatcould affect feasibility (the need to meet Canadian standards, the edge lamella beams are toothin for the bolts required to attach the sinus plates, the lamella beams may not be strongenough for bolts, and the height of the adjacent road surfaces would need to increase by 20mm). They also ask questions to gain a better understanding of the issue.

• Mageba follows up on October 6, 2009, addressing some of the technical factors noted aboveand indicating a cost of roughly EUR 50,000 for engineering and the supply of the sinus platesfor one joint. They leave outstanding the issue of increasing the height of the adjacent roadsurface.

• TransLink formalizes a request to Mageba for information concerning sinus plates in a letterdated October 26, 2009, and proposes a meeting with them in Vancouver.

It’

ACOUSTICS NOISE VIBRATION www.hgcenglneering.com

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TransLink Page 3Golden Ears Bridge Expansion Joint Sound Study Draft July 11, 2013

Following up on the meeting with TransLink, Mageba suggests in an email of November 5,

2009, a “very sensible” approach of using “hump” seals (a modified rubber seal used in placeof the existing seal between lamella beams) to address “pumping” noise.

• Collings Johnston Inc. summarizes the status of the investigation in a memorandum datedNovember 11, 2009. The memorandum notes the two options suggested by Mageba (sinusplates and hump seals), and also cites research from Japan described by Wakefield Acoustics,leading to a third option of filling the void between the lamella beams with compressiblematerial. Plans are made to specify rubber chips and to arrange a field test of this third option.

• Hatfield Consultants, in an email dated November 17, 2009, forwards information to Magebaconcerning the test of rubber chips. Mageba, in an email dated November 18, 2009, supportsthe test, provides recommendations regarding the addition of a binder to the rubber crumbs,and indicates that Japanese trials support the effectiveness of the solution.

• In an exchange of emails on November24 and 25, 2009, TransLink and Mageba make initialplans to install and test hump seals. TransLink indicates that they had committed to the publicthat if the hump seals prove ineffective, sinus plates would be installed.

• In an email from TransLink to Mageba, dated March 31, 2010, TransLink acknowledges thatneoprene material resulted in an improvement of only 3 dB, and requests information on theJapanese material, and also requests performance guarantees for the sinus plates.

• Mageba replies by email on April 1 and 14, 2010, discussing technical details for the possibleoptimization of a filler material, or the use of hump seals. They do not provide a performanceguarantee for the sinus plates.

• In a document dated May 27, 2010, TransLink provides an update on the progress of thedevelopment of noise mitigation for the expansion joints. They indicate that research showsthat the filler material may prove beneficial, noting that hump seals are unlikely to providesimilar improvements and that sinus plates present technical difficulties and no guarantee ofperformance.

• In an email June 7, 2010, Wakefield Acoustics indicates that their research shows that fillingthe void with an engineered material offers the potential of a good improvement and suggestsoptimizing the acoustical properties of the material along the lines of the Japanese experience.TransLink passes this email on to Mageba the same day, indicating that they are testing theacoustical properties of various materials at the University of British Columbia and requestsinformation on the Japanese material if available.


87- 114 -


In an exchange of emails between Mageba and TransLink on June 14, 2010, Mageba indicates

they were contacted directly by the public asking why sinus plates were not installed, and ifthey can now be retrofitted. TransLink responds to Mageba and passes on the May 27, 2010

update document. TransLink advises that research by Wakefield Acoustics suggests theJapanese material should meet requirements for noise reduction.

In an exchange of emails between Mageba and TransLink on June 15, 2010, Mageba indicatesthey will forward a sample of the Japanese material, and provides information on installationconsiderations.

2.2 Wakefield Acoustics Reports

TransLink provided HGC Engineering with three summary reports prepared by Wakefield Acoustics

Ltd. in respect of the expansion joint noise and its impact at the Pitt Meadows community. The first

was a letter to TransLink dated September 12, 2011, the second a more in-depth report dated October

20, 2011 entitled “Assessment and Control of Golden Ears Bridge Expansion Joint Noise (2009 to

2011), and a third dated November 25, 2011 highlighting taking points for a public meeting. There

is a great deal of redundancy amongst the documents, however the salient points are presented

below:

• Wakefield Acoustics Limited appears to have become formally involved in 2009 to considercroaking sounds from the expansion joints which was impacting the Pitt Meadows community.Previous work by BKL Consultants had addressed the general noise impact from vehiculartraffic on the highway.

• Wakefield Acoustics’ initial investigation concluded that the croaking sounds were of suchbrief duration that they did not contribute significantly to the overall daily average noiseimpact, but were “generally clearly audible over the ambient community noise, even during thedaytime, and their suddenness, repetitiveness and unique tonal character made themparticularly intrusive.” It was also quickly determined that only southbound vehicles appearedto regularly create croaking sounds, and only while passing over the south abutment joint.

• Two noise generation mechanisms were initially considered to account for the croaking. It wasconsidered that the impact of the tires on each of the regularly spaced lamella beams wouldcreate sound at a frequency governed by the speed of the vehicle and the spacing of the beams,but typically at less than half the observed frequency of 630 Hz, and this mechanism was ruledout. Wakefield Acoustics noted that Japanese research revealed that pulses of air in the joint


88- 115 -


cavity could excite acoustic resonances in the 630 Hz frequency range, and that this could betreated by filling the cavity with compressible material.

• Wakefield Acoustics considered two other mitigation measures: barriers and sinus plates.Barriers could not feasibly be placed in an effective location given the orientation of thereceivers, and the sinus plates were determined to not offer an adequate reduction.

• Theoretical calculations were made based on the principal ofa HelmhoLz resonator, whichsupported the acoustic resonance mechanism.

• Initial attempts to fill the joint with rubber crumb proved to be only minimally effective, butoptimisation of the material based on acoustical testing led to the selection of a geotextilecovered by neoprene strips.

• This final treatment was installed and assessed in August of 2011 and it was concluded that areduction on the order of 10 dB had been achieved.

Subsequent to HGC Engineering being retained to review the material, Wakefield Acoustics

prepared an additional report dated March 26, 2013 which contained sound level data measured on

the Golden Ears Bridge near the expansion joints and in the community. The report presented one-

third octave band spectra of sound levels and a statistical analysis of the sum of the sound pressure

levels measured in the 500, 630, 800 and 1000 Hz one-third octave bands, as measured at the side of

the bridge before the treatment with geotextile and neoprene seals, and a limited amount of data

measured afterward. The spectral sound data measured after treatment shows that the geotextile

covered by neoprene strips eliminated the 630 Hz tone, and the statistical analysis shows an

improvement of 10 dB in the selected frequency bands. A statistical analysis was also completed for

overall A-weighted sound intrusions in the community, and was described in the report.

The report concludes that a reduction of the croaking noise on the order of 8 to 9 dB was achieved at

the most impacted residential location on Wildwood Crescent in the Pitt Meadows community, as a

result of the geotextile and neoprene seals being inserted between the lamella beams.

gACOUSTICS NOISE VIB RATION www.hgcenglneerlng.com

89- 116 -


2.3 University of British Columbia Acoustic Testing

The Acoustics and Noise Research Group at the University of British Columbia tested a series of

potential filler materials to determine the sound absorption coefficients as a function of frequency.

Their first report was dated May2010, and a second report testing a sample of the Japanese foam

was dated June 2012. The results show that the geotextile had a good balance of dry and wet

absorption coefficients in the critical 500 to 600 Hz frequency range: 0.8 (dry) and 0.2 (wet). The

wet performance of the geotextile material was better than the other materials selected and was

comparable to the results for the Japanese foam.

HGC Engineering has no concerns related to the validity of the testing. The Acoustics and Noise

Research Group at the University of British Columbia is headed by Dr. Murray Hodgson, who is

very well respected in the international acoustics community, and the testing was completed using an

impedance tube which is a fairly common and reliable test governed by ASTM E1050 Standard Test

Methodfor Impedance andAbsorption ofAcoustical Materials Using a Tube, Two Microphones and

a Digital Frequency Analysis System.

2.4 Mageba Documentation

TransLink provided HGC Engineering with two documents produced by Mageba that describe the

Tensa Modular Type LR Expansion Joints used on the Golden Ears Bridge.

One was a product brochure that is very similar to the document currently available online at

http://www.mageba.in/data/docs/download/2603/enIN/PROSPECT-TENSA-MODULAR-LR-ch-

en.pdf. The brochure describes an optional patented noise-reducing surface. Referred to as “sinus

plates”, the design eliminates straight edges perpendicular to the direction of travel and ensures that

the tires rolling on the joint continuously grip the surface.

The Mageba brochure indicated that it is possible to retrofit existing modular expansion joints with

sinus plates, although this requires the surface level of the road adjacent to the joint to be increased

by approximately 20 mm.


90- 117 -


The second document provided by TransLink to HGC Engineering was a PowerPoint presentation by

Mageba, dated November 2008, which was focused on the implementation of the sinus plates along

with examples.

The printed version of the brochure indicates that sinus plates provide a sound reduction of 70%

(equivalent to 5 dB) while both the website and presentation slides dated November 2008 indicate

that they provide a sound reduction of 80% (equivalent to 7 dB). None of the Mageba literature cited

above refers to “hump” seals, or to filling the joints with compressible material.

25 Research Papers

There is a community of researchers actively engaged in research into noise produced by modular

expansion joints, notably in Japan and Australia. HGC Engineering has endeavoured to collect as

many English-language technical papers and other publications which are relevant to this topic as

possible, in order to become more familiar with the on-going efforts of the international community.

It is acknowledged in the literature that vehicles passing over any type of expansion joint produce a

noticeable sound louder than the typical tire/roadway noise, but that the noise produced by modular

expansion joints tends to be louder than other types ofjoint [1},[2],[31.

Recent literation into the mechanism by which modular expansion joints of a type similar to the

Mageba lamella beam product identifies two different phenomena, one causing sound above the

roadway or bridge, and the other radiating sound to areas below.

An air resonance in the gap under a tire, formed between the tire, the rubber seal, and the transverse

beams, was verified experimentally as producing sound above the roadway in [2], which found

resonances near 700 Hz for the described full-scale experiment. This resonance is excited when the

air in the gap is suddenly compressed by the action of the tire, and radiates sound to the environment

above the joint [2]. Similar acoustic resonances in the air volume below the tire are also described in

[1] as causing noise above the road surface. Interestingly, [1] also describes mitigation similar to a

sinus plate, yielding a 5 to 6 dB reduction, but also realized a greater sound level reduction by

closing the gaps with an elastic material.

ACOUSTICS NOISE VIB RATION www.hgcenglneering.com

91- 118 -


[2] also describes work done to mitigate this type of noise by filling the gaps between beam elements

in a modular expansion joint. In this case, a rubber material was placed in the gaps, and a significant

sound level reduction was realized. This result, and the result describe in [1] suggests that filling the

modular joint gaps is a viable strategy for mitigating above-joint noise.

The tests undertaken by Wakefield Acoustics on the bridge are described in a paper presented to the

Canadian Acoustical Association conference [4]. The paper summarizes some of the above-joint

noise research described above, and discusses various tests. A 2 mm diameter “crumb rubber” placed

in the gaps resulted in a 3 dB reduction in the frequency band between 400 and 900 Hz, as did a

neoprene rubber strip glued between the beams with no crumb rubber. The use of geotextile material

capped with 6 mm thick neoprene rubber strips is reported to have resulted in a 10 dB reduction in

the frequency band.

The new Tacoma Narrows Bridge appears to have had a similar issue with above-joint noise from a

modular expansion joint [5], although the report does not discuss the mechanism of noise generation.

The report describes the construction of small absorptive acoustic barriers at the sides of the bridge

in the vicinity of the joints. This strategy would clearly not be suitable for noise radiating along the

roadway.

Below the joint, [21 identified a different noise generating mechanism, involving structural

resonances of the joint’s beams, possibly amplified by further acoustic resonances of the cavity

below the joint system as a whole (i.e. the cavity between the joint assembly and the bridge

abutments or other superstructure. The dominant frequency modes of this mechanism were found to

be below 200 Hz. This mechanism was further explored in [6], which agreed that both structural

vibration modes of the joint beams and acoustic modes of the larger cavity below the joint assembly

are likely responsible for below-joint noise. Further numerical modelling of the below-joint noise is

described in [7] and concludes that both structural vibration modes and acoustic modes are factors.

[8] discusses the implementation of a series of Helmholtz resonator to absorb sound in the cavity

below the joint structure. The resonators were designed to absorb sound at known acoustic modes of

the below-joint cavity, and after implementation, the tests showed a reduction of about 10 dB in the

affected frequency range, when measured at some locations below and beside the bridge. This work


92- 119 -

TransLink Page 9Golden Ears Bridge Expansion Joint Sound Study Draft July 11,2013

strongly supports the acoustic resonance theory for below-deck noise. Again, low frequency modes

(below 200 Hz are discussed).

[1] Martner 0. (1996). Noise emission of constructions for bridge-to-road crossings, Proc. Inter-Noise 96, Liverpool, UK, 211-2 14

[2] Ravshanovich K.A., Yamaguchi H., Matsumoto Y., Tomida N. and Uno S. (2007) Mechanism ofnoise generation form a modular expansion joint under vehicle passage, Engineering Structures,29(9), 2206-2218

[3] Ancich E.J. (2011). Structural Dynamics of Modular Bridge Expansion Joints Resulting inEnvironmental Noise Emissions and Fatigue, PhD Thesis, Faculty of Engineering and InformationTechnology, University of Technology, Sydney, Australia.

[4] Wakefield C.W. and Marriner D.E. (2011). Analysis and control of bridge expansion jointcroaking noise, Canadian Acoustics, 39(3), 138-139.

[5J Sexton T. (2011). Expansion joint noise reduction on the new Tacoma Narrows Bridge,Washington State Department of Transportation, Report Number WA-RD 785.1

[6] Ghimire J.P., Matsumoto Y. and Yamaguchi H. (2008). Vibro-acoustic analysis of noisegeneration from a full scale model of modular bridge expansion joint, Noise Control EngineeringJournal, 56(6), 442-450

[7] Jahabindra P., Matsumoto Y., Yamaguchi H. and Karahashi I. (2009). Numerical investigation ofnoise generation and radiation from an existing modular expansion joint between prestressedconcrete bridges, Journal ofSound and Vibration, 328(1-2), 129-147

[8] Ancich E.J. and Brown, S.C. (2004). Modular bridge joints — reduction of noise emissions by useof helmholtz absorber, Proc 5th A USTROADS Bridge Conference, Hobart, Australia, 19-21.

3 SOUND MEASUREMENTS AND ANALYSIS

3.1 Sound Measurements on Bridge Deck

A series of sound measurements were undertaken by HOC Engineering from the sidewalk at the west

side of the bridge on March 1, 2013, during typical morning traffic flow. The weather was not ideal

for measurements — intermittent light rain occurred before, during and after the measurements — but

efforts were taken to minimize the duration the equipment was exposed to moisture, and the

background sound due to falling rain was negligible.

The measurements were conducted using a two-channel Hewlett Packard type 3569A real time

frequency analyser equipped with a B&K type 4188 microphone. The instrumentation is calibrated

ACOUSTICS NOISE ViBRATION www.hgcengineering.com

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TransLink Page 10Golden Ears Bridge Expansion Joint Sound Study Draft July II, 2013

by NIST traceable laboratories on an annual basis, and correct calibration ofthe instrumentation was

verified on site using a portable vibration calibrator.

Measurements were conducted on the sidewalk beside the southbound lanes near the North

Approach Joint and at North Stay Joint (M6), in line with the centreline of the joint and also, for

consistency with the earlier measurements conducted by Wakefield, at 15 m north of the centreline

of the joint. At this latter position, the rear of the vehicles was oriented toward the microphone. The

microphone was placed at a height of approximately 1.5 m.

It is not as easy as it may seem to capture the sound of the vehicle traveling over the joint during

normal traffic flow. There is a wide range of vehicle types traveling at a various speeds and in

various lanes, and there are sound intrusions from the engine of the vehicles and from the

tire/pavement interaction, and these are again dependent on many factors including how tightly

bunched the vehicles are. To help resolve these difficulties, HGC Engineering discriminated against

peak sound levels that were unduly influenced by engine noise, and then used a statistical approach

which assessed the peak intrusions without regard to vehicle type or speed.

Sound levels were measured as one-third octave band frequency spectra on a 1/8 second basis over

various periods of thirty seconds each. To differentiate the peak noise occurring when the vehicle

encountered the joints from the peak noise of the engine and tires, the overall A-weighted sound

pressure level, and the sum of the sound pressure levels in the 400, 500, 630, 800 and 1,000 Hz one-

third octave bands (the mid-frequency bands) were plotted as a function of time to reveal the sharp

peaks where the sound in the mid-frequency range was dominant. Figure 1 presents a sample of the

measurement made over one thirty second long time period at 15 m north of the M6 joint.

At each of the peaks attributed to the passage of a vehicle over the joint, the frequency spectrum of

the sound occurring in that 1/8 second was extracted from the data and plotted. Figures 2 through 5

illustrate the frequency spectra of each of the individual peaks measured at each of the four

measurement locations. The linear average of the spectra measured at each location is shown as

heavy black circles on each figure. It is clear that there is a high degree of variation between the

sounds produced during individual joint-crossing events, while at the same time the average curves

gACOUSTICS NOISE VIBRATION www.hgcengineering.com

94- 121 -


all demonstrate a similar shape with the maximum sound level occurring in the 500 Hz one-third

octave band.

The average of the measured peak intrusions at the four locations is presented in Figure 6. Also

presented on the figure is the average spectrum from the data measured by Wakefield Acoustics in

August of 2009 at 15 metres north of the NAV joint, prior to the implementation of the joint filler.

Considering the data measured by HGC Engineering, there is good consistency between the

measurements taken at the M6 and NAV expansion joints, and as expected the levels are lower by

approximately 5 dB at the location 15 m north of the centreline of the expansion joints than at the

location on the centre line of the expansion joint. It is readily apparent from data in the figure which

was measured 15 metres north of the joint centrelines, that the peak at 630 Hz measured by

Wakefield Acoustics prior to the implementation of the joint filler has effectively been replaced by a

peak at 500 Hz which is approximately 7 dB lower.

While the one-third octave band measurements conducted by HGC Engineering suggest that the peak

sound level from the passage of the vehicles over the joints tends to occur in the 500 Hz band, this is

not a very precise estimate of the frequency. To explore this further, an additional series of

measurements were conducted with the analyser configured to compute a Fast Fourier Transform of

the sound data to yield a discrete frequency spectrum at a resolution of 5 Hz. The resulting spectra

can then be used to determine the peak frequency with some precision. Figure 7 presents a scatter

plot of the amplitude of the peak sound levels, and the frequencies at which they occur, for thirteen

vehicles passing over the M6 expansion joint. On average, the frequency at which the peak sound

level occurs is 504 Hz, but the peak varies widely between 375 Hz and 685 Hz.

3.2 Assessment of Expansion Joint Filler Effectiveness

The data presented in Figure 6, described in the preceding section, suggests that the geotextile and

neoprene seals have effectively reduced the croaking sound by 7 dB. However, the spectral data

from Wakefield Acoustics that was measured prior to the implementation of mitigation was based on

a small selection of different vehicle types rather than on statistical data from many different events.

HGC Engineering did not have the opportunity to conduct measurements before the mitigation was

installed. In order to assess the effectiveness of the geotextile and neoprene seals installed at the

ACOUSTICS NOISE VIB RATI ON www.hgcengineering.com

95- 122 -

TransLinkGolden Ears Bridge Expansion Joint Sound Study

Page 12Draft July11, 2013

NAV and M6 expansion joints on the Golden Ears Bridge from a statistical approach, HGC

Engineering has compared the sum of the sound levels in the 500, 630, 800 and 1,000 Hz one-third

octave bands taken from the data measured by HGC Engineering, and compared it to the same type

of data (the sum of the sound levels in the 500, 630, 800 and 1,000 Hz one-third octave bands)

described in tabular form as presented by Wakefield Acoustics in the report dated March 26, 2013.

Unfortunately, there are differences in the measurements conducted by HGC Engineering and by

Wakefield Acoustics, from which the spectral data can be taken. Specifically, there is variation in

the joints where the sound was measured, the number of vehicles measured, and the distance from

the joint centreline to the measurement location. Table I summarizes the available data.

ACOUSTICS NOISE

Table I: Summary of the Number of Measurement Data Points Available,by Joint, Measurement Distance, and Joint Treatment.

Distance Northof Joint

Centreline

WAKEFIELD ACOUSTICS HGC ENGINEERING,

NAV Joint,Untreated

NAV Joint,with Geotextileand Neoprene

Seals

M6 Joint, withGeotextile andNeoprene Seals

NAV Joint,with Geotextileand Neoprene

Seals

Om 30 31

7m 30 30

15m 25 32

A summary of the average measured sound levels and the standard deviations from each of the data

sets identified in Table I are shown in Table II. The average sound levels represents the summation

of the sound levels in the one-third octave bands centered on 500, 630, 800 and 1,0000 Hz which

were measured during the 25 to 32 random traffic tire/joint interactions in each data set.

VIBRATION www.hgcenglneerlng.com

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Page 13Draft July 11,2013

DistanceNorth of

JointCentreline

NAV Joint, Untreated

AverageSoundLevel(dB)

NAV Joint,with Geotextile and

Neoprene Seals

AverageSoundLevels(dB)

M6 Joint, withGeotextile and

Neoprene Seals

NAV Joint, withGeotextile and

Neoprene Seals


Although sound pressure levels were not measured at a 7 m offset distance by HGC Engineering, the

average sound levels at that particular distance for both NAV and M6 were estimated using a linear

interpolation. The calculated results are summarized in Table III.

Table III: Comparison of Average Sound Levels of Treated and Untreated Expansion Jointsat 7m North of Joint Centreline

FIiiLD ACO1JSTICS LjfHGC ENGINEERIN9(Measured, Interpolated) At 4

NAV Joint, . NAV Joint,. . M6 Joint, with

NAV Joint, with GeotextileGeotextile and with Geotextile

Untreated and NeopreneNeoprene Seals

and NeopreneSeals Seals

Average Sound90 2 79 9 81 1 79 3

Level (dB)

As shown in Table III, the post-treatment results interpolated from the HGC Engineering data to a

location 7 m north of the joint centrelines, at both the M6 and NAV joints, bound the measurement

data from Wakefield Acoustics. Thus, the statistical analysis suggests a sound pressure level

reduction of approximately 10 dB in the frequency range of interest. The difference in the post-

treatment data, based on the data from Wakefield Acoustics and from HGC Engineering are minimal,

NOISE www.hgcenglneering.com

Table II: Summary of the Average Sound Levels and Standard Deviations,by Joint, Measurement Distance, and Joint Treatment.

f WAKEFIELD ACOUSTICS HGC ENGINEERiNG.,,..

StandardDeviation

(dB)

StandardDeviation

(dB)


StandardDeviation

(dB)

StandardDeviation

(dB)

Om 83.5 5.7 81.5 4.9

7 m 90.2 5.0 79.9 3.5

15 m 78.5 5.3 77.1 4.3

ACOUSTICS VIBRATION

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providing additional evidence that the geotextile and neoprene seals filling the gap between the

lamella beams are effective in providing noise control at both joint locations.

3.3 Technical Review of Selected Mitigation Approach

Modular bridge expansion joints such as the Tensa Modular Type LR Expansion Joints

manufactured by Mageba used on the Golden Ears Bridge generate noise in four ways:

1. Any change in the surface of the road results in a discernible change in the noise of traffic as

the tires move from one surface to another. This can be observed as vehicles pass from asphalt

to concrete surfaces, or where surface treatments on a roadway change (e.g., a change from

longitudinal to transverse tining on a concrete road). This type of difference in sound

characteristic is of minimal importance to the situation, and is not the concern here.

2. Tires encountering a physical discontinuity will transmit an impact force throughout the tire

and vehicle body which causes vibration and noise. As an example, a pothole causes noise in

this way. Tires impacting an evenly spaced series ofdiscontinuities (e.g., rumble strips and

cattle gates) will tend to produce a noise with a characteristic tone at a frequency governed by

the spacing of the discontinuities and the speed of the vehicle. The multiple lamella beams

running normal to the direction of traffic cause multiple similar, but smaller, impacts. This

phenomenon could lead to a characteristic tone related to the spacing of the beams and the

vehicle speed, but will also create noise related to dynamic properties of the tire, vehicle, joint

and bridge.

3. Research indicates that modular expansion joints of a type similar to the Mageba modular joint

could cause low frequency tones (roughly 200 Hz and below) related to the resonant

frequencies of the longitudinal beams, coupled with acoustic resonances of voids below the

joint assembly as a whole, voids formed between the joint assembly, and bridge abutments or

other superstructure elements. This noise tends to be important only in areas below the level of

the bridge and is not a factor at the Golden Ears Bridge.

4. Research has also identified that this type of modular expansion joint can be prone to an

acoustic air resonance which is created in the void or cavity formed between the tire, two


98- 125 -


adjacent lamella beams, and the EPDM seal. This resonance has a characteristic tone unrelated

to vehicle speed, but related to the geometry of the cavity. Research indicates that this

mechanism of sound generation tends to be important in areas above the bridge surface. In the

literature it appears that this type of sound tends to be important in the middle frequency range,

approximately 500 to 800 Hz. This acoustic resonance, while not a classic Helmholtz

resonator, must certainly function in a similar way.

Noise heard in the Pitt Meadows community may be affected by noise caused, to varying degrees, by

all four mechanisms. However, because the sound level measurements conducted on the bridge near

the joints and in the Pitt Meadows community show a noise with a characteristic frequency in the

630 Hz one-third octave band which is unrelated to vehicle speed, and because these measurements

are all conducted above the level of the bridge, or with a clear line of site to the upper surface of the

joint, it is reasonable to assume that the objectionable croak is dominated by noise generated by the

fourth mechanism outlined above. Nonetheless, it should be noted that there will still be some sound

related to the remaining mechanisms, and even if the croaking were entirely eliminated, a noise with

a distinct quality would still be produced at the joint.

It should be reiterated that mechanism four, noted above, is not fully understood in the literature. The

acoustic resonance of the air under the tire is not a classic Helmholtz resonance. A classic Helmholtz

resonator— blowing air over a bottle top to produce a tone is a typical example — exists where a

volume of air vibrates in a confined space at a specific frequency governed by the mass ofvibrating

air, and the stifthess resulting from changes in air pressure in the sealed volume. This is not exactly

the case for the tire moving over the gap since the volume of air is not fully enclosed or even easily

definable, and the vibrating air mass is even less so. Nonetheless, the research and analysis

undertaken by Wakefield Acoustics certainly do indeed point to some form of acoustic resonance.

To mitigate this fourth type of noise from a modular expansion joint, there are two principal

strategies that emerge from the literature, and both were considered by TransLink. A third option —

constructing local barriers near the joint — could be effective in some cases, but not in this case due to

the location of the Pitt Meadows community in relation to the direction of vehicle travel.


99- 126 -


The two options are the installation of a series of diamond-shaped horizontal plates on top of the

transverse joint beams (Mageba terms these sinus plates), and filling of the void formed under the

tire, above the joint seal, and between each pair of beams.

Mitigation: Sinus Plates

Sinus plates consist of specially shaped metal plates that cover the lamella beams and are available

from Mageba as a retrofit. Since they would tend to reduce the impact forces between the wheel and

beams, sinus plates have the advantage of potentially improving noise generated by any of

mechanisms 2, 3, and 4 as outlined above, whereas filling the void addresses only mechanism 4.

However given that the evidence suggests that mechanism four is the principal problem, this

difference by itself may be of little consequence. Based on company literature and other technical

papers, the installation of such plates could be expected to reduce the sound emitted by the joints by

approximately 5 to 7 dBA. Nonetheless Mageba has not provided TransLink with a guarantee of the

degree of noise reduction.

Perhaps the greatest disadvantage of using sinus plates as a retrofit is that significant reconstruction

of the bridge deck would be required to accommodate the increased height caused by installing the

sinus plates on top of the existing lamella beams.

Further disadvantages include potential issues of fatigue of the plates and lamella beams, and the fact

that the plates must be removed in order to maintain the joints. For example, it is not possible to

clean debris from the joint with the sinus plates in place.

It is also important to note that sinus plates still provide a change in surface texture, and they should

not be expected to completely eliminate characteristic sound generated at the joint.

Mitigation: Filling the Gap

Given that the data indicates that the croaking noise is related to an acoustic resonance of the air in

the joint voids, completely filling the voids should, in theory, completely eliminate the resonance.

This is likely not a realistic expectation given the remaining questions about the noise generating

mechanism, and the limitations imposed by requiring a varying gap width.

ACOUSTICS NOISE VIBRAI1 ON www.hgccngineering.com

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The filling of similar expansion gap voids is described in the literature, and attempting this

mitigation measure is certainly reasonable. The specific approach chosen by TransLink was to install

an acoustically absorptive and resilient filler material in the space between the lamella beams above

the rubber seal. Despite the uncertainty associated with the exact mechanism, the treatment was

optimized in terms of the acoustic absorption properties through testing at the University of British

Columbia and its ability to withstand the environment. The selected treatment utilized geotextile

material formed into a V shape with a solid neoprene cap installed in the gaps between the lamella

beams.

The information received from Wakefield Acoustics regarding sound level measurements conducted

before and after installation of the filler material suggests that a 10 dB reduction at the key frequency

of the sound emitted from the joints was achieved. The data measured by HOC Engineering also

suggests a similar degree of reduction when compared to earlier data from Wakefield Acoustics.

Importantly, this reduction is on the same order, and may be somewhat greater, than the reduction

suggested by Mageba for the sinus plates.

Nevertheless, the tests conducted to date have not been conducted in an ideally controlled fashion

and as a result there remains some uncertainty as to the details of the mechanisms of noise generation

and the exact degree of effectiveness of the mitigation. The influence of vehicle type, vehicle speed,

tire width, and the distance and directivity from the joint crossing to the microphone have not been

fully explored.

While the joint filling solution is certainly easier to implement than sinus plates, there is a significant

maintenance-related disadvantage to this solution which is that the neoprene currently in use has an

observed tendency to degrade and become detached from the joint. Frequent maintenance will be

necessary to keep the mitigation effective.

Mageba does not appear to publish such a solution as a common mitigation measure, but hump seals

which are a modification of the standard EPDM joint seal, and partially fill the voids, are available

from Mageba. Hump seals would change the acoustic resonance of the joint voids, and would likely

be less prone to failure than the neoprene strips currently in use, but the acoustic benefit of the hump

seals is not known at this time.


101- 128 -


Mitigation: Summary

Both the sinus plates and the idea of filling the joint voids are supported as potential mitigation

measures by the literature, and both have disadvantages. The data collected to date indicates that the

joint-filling strategy has been acoustically effective; not completely, but the available data indicates

that this reduction in the noise has been on the same order as the sinus plates would be expected to

provide. Because of this, there does not appear to be a compelling case to consider implementation of

sinus plates at this time, since it is not clear that a further noise reduction would be a reasonable

expectation.

4 CONCLUSIONS

Modular bridge expansion joints produce noise via different mechanisms. In this case, considering

the technical literation on the subject, the nature of the complaints, and the measurements and

analysis conducted by Wakefield Acoustics, it appears highly probable that the objectionable

croaking noise, dominated by a broad peak in the frequency spectrum which is within the 630 Hz

one-third octave band irrespective ofvehicle speed, is caused by an acoustic resonance of the air in

the joint voids formed between the tire, the EPDM joint seals and each pair of adjacent lamella

beams.

The literature supports two strategies for mitigation of this noise, sinus plates or a similar system,

and filling of the joint voids with a compressible material. Both of these solutions offer a degree of

potential improvement to the sound, both have advantages, and both have disadvantages.

Maintenance of the mitigation measures is an aspect of the design that needs to be considered by

TransLink in any event.

In this case, TransLink opted for the solution of filling the voids with an acoustically absorptive

fabric covered with a neoprene seal. Sound level measurement data and analysis provided by

Wakefield Acoustics indicate that the mitigation has resulted in an improvement in the critical

frequency band of about 10 dB. This is on the same order, and may be somewhat greater, than the

sound level expected for the sinus plates. Because of this, there does not appear to be a compelling

ACOUSTICS NOISE VIBRATIoN www.hgcengineer.ng.com

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TransLink Page 19Golden Ears Bridge Expansion Joint Sound Study Draft July 11,2013

case to consider implementation of sinus plates at this time, since it is not clear that a further noise

reduction would be a reasonable expectation.

In summary, it is concluded that TransLink has followed a reasonable acoustic mitigation strategy to

deal with noise from expansion joints. HGC Engineering’s review of the data provide by Wakefield

Acoustics indicates that the mitigation has been effective, although regular inspections and a

maintenance program will need to be put in place to ensure continuous mitigation in the future.

ACOUSTICS NOISE VIBRAtION www.hgcengIneering.com

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TransLinkGolden Ears Bridqe Expansion Joint Sound Study

Page 20Draft July11, 2013

ACOUSTICS NOISE VBRATIGN www.hgcenglneerlng.com

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Tra nsLinkGolden Ears Bridge Expansion Joint Sound Study

Page2lDraft July 11,2013

!-)

,

wwwiigcenglneering.com

Figure 2. Frequency Spectrum of 25 Vehicles Passing Over Expansion Joint MG(measured 15m to the north), March 1, 2013.

90

85

80

70

65

60

55

5063 80 100 125 160 200 250 315 400 500 630 800 1000’ 1250 1600 2000 2500 3150 4000 5000 6300 8000 A

Frequency (Hz)

ACOUSTICS NOISE VIBRATION

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TransLin k

Golden Ears Bridge Expansion Joint Sound Study

Page 22

Draft July 11, 2013

-

.

‘<

www.hgcengineering.com

Figure 3. Frequency Spectrum of 30 Vehicles Passing Over Expansion joint M6,

(measured in line with joint) March 1, 2013.

90

. 75

_______

-J

170

65

_______ _____ ______________________ ______ ____

60

55

5063 80 1) 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 A

Frequency (Hi)


106- 133 -


ACOIJSTIIS NOISE VIBRATION



/Fq\11ffc)

Figure 4. Frequency Spectrum of 32 VehIcles Passing Over Southbound NorthApproach Viaduct Joint (measured 15m to the north), March 1, 2013.

:/\70

65

60

55

50

T

63 80 1 125 160 200 250 315 400 500 630 8(X) 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 A

Frequency (Hz)

107- 134 -

TransLink

Golden Ears Bridge Expansion Joint Sound Study

Page 24

Draft July 11,2013

.-.-

‘

I

,t

,‘

—

www.hgcenglneering.com

FigureS. Frequency Spectrum of 31 Vehicles Passing Over Southbound North

Approach Viaduct Joint (measured in line with joint), March 1, 2013

90

85

80

75

j70

____ _____ ______________________________________________________

65

60

55

63 80 100 125 160 200 250 325 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 AFrequency (liz)


108

- 135 -



as

Figure 6: Comparison of Frequency Spectra of Average Sound Levels Measured atExpansion Joints by HGC Engineering (after treatment) and Wakefield Acoustics

(before treatment).

.

63 80 100 125 160 260 250 315 400 560 630 80) 1000 1250 1600 2600 2500 3150 40)0 5000 6300 8000 A

Frequency (Hz)

80

. 75

4,

170

65

60

55

ACOUSTICS

—--Wakefield Acoustics, Untreated, iSm North of NAV, August 2009.HGC Engineering, iSm North of M6, March 2013.

—I—HGC Engineering, Centreline of MG, March 2013.—*— HGC Engineering, 15m North of Southbound NAV Expansion Joint, Mardi 2013.—— HGC Engineering, Centreline of Southbound NAV Expansion Joint, March 2013.

VIBRATION www.hgcengineeriag.comNOISE

109- 136 -

TrarisLinkGolden Ears

ACOUSTICS

Bridge Expansion Joint Sound Study

NOISE VIBRATION


Figure 7.. Peak Frequency of Fast Fourier Transform of Sound LevelMeasured for 13 Vehicles Passing Over M6 Joint, March 1, 2013.

800

700

600

5O0

.40O

U.

3O0

200

100

0

,

.....

62 64 66 68 70 72 74

Peak Sound Level (dB)76 78


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APPENDIX A

Reference Materials

(Under separate cover)

ACOUSTICS NOISE VIB RATION www.hgcenglneering.com

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ATTACHMENT F

WakefieldAcousticsCONSULTING ACOUSTICAL ENGINEERS

14-1990-1April 27, 2015

Translink

1600 - 4720 KingswayBurnaby, BC V5H 4N2

Attention: Bob Moore P. Eng., C.Eng., MICE - Golden Ears Bridge

Regarding: Golden Ears Bridge Modular Expansion Joint Noise — Follow-up NoiseMeasurement

Dear Bob,

As requested, follow-up noise measurements of vehicles passing over the Golden Ears Bridge modularexpansion joints (MEJs) have been completed during April 2015. The purpose of these measurementswas to quantify levels of residual “croaking” noise occurring at this time and verify the ongoingeffectiveness of the geotextite/neoprene seals in achieving a substantial noise reduction. This reportpresents the methodology and results of a comparison of noise levels measured March 2010, before thegeotextile/neoprene seal treatment, with current noise levels in April 2015, five years after thetreatment.

Methodology

Monitoring Locations, Times and Weather Condition

Noise monitoring was conducted at the locations and times indicated in Table 1 where the weatherconditions are also noted.

COMMUNITY NOISE IMPACT ASSESSMENT S CONTESt. I TRANSPORTATION NOISE ARCHITECTUR1IL ACOUSTICSSUILOINO NOISE CONTROL I NOISE S VI8RATION MEASUREMENTS CONTROL TRAINING 8 LEPERS TESTIMONY

3012250 Oak Bay AvEnue. Victoria. Canada VER 105 T 250370 9302 F 2503709309 5 kifaCwakefloIdacousticcom wake Idacansticscom

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Golden Ears Bridge Modular Expansion Joint Noise April27, 2015Follow-Up Noise Measurement

Table 1: Noise Monitoring Locations, Times and Weather Conditions

Start StopTime Time

WeatherSite Location da/mo/yr da/mo/yr

Conditionshh:mm hh:mni

-7 m1 offset from transverse 9/04/15 9/04/15la centerline (west side) of the 13:38 13:49

NAV2MEJ

-7 m offset from transverse 9/04/15 9/04/15lb centerline (west side) of the 13:57 14:24

Dry conditions prevailed with clear skies,negligible wind and daytime highs of 15°C.

M6MEJ

-7 m offset from transverse 9/04/15 9/04/15la centerline (west side) of the 14:25 15:3 1

NAV MEJ

2-565 m offset from the 9/04/15 9/04/15 Dry conditions prevailed with clear skies,

NAV MO 01:20 10:46 negligible wind and nighttime lows of 4 °C.

1. The minus sign indicates the longitudinal offset relative to the transverse centerline of the MEl in thedirection opposite to the traffic flow.

2. NAV stands for North Approach Viaduct.

Site la and Site lb were the control sites representing the NAV and MG MEJs respectively. Site 2was the residential noise monitoring location representative of the Wildwood residential area. Site2 was located 565 m to the north of the NAV MEl at the southeast corner of Wildwood Crescent S.(see Figure 1).

Poge2of7wakefieldacoustics.com

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Figure 1: Golden Ears Bridge showing noise monitoring sites.

April 27, 2015

AA Page 3 of 7wakefleldacoustics.com

Golden Ears Bridge Modular Expansion Joint Noise

Follow-Up Noise Measurement

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Golden Ears Bridge Modular Expansion Joint Noise April27, 2015

Follow-Up Noise Measurement

Instrumentation and Procedures

A Larson-Davis Real-Time Analyzer (RTA) Model 2800 was used to conduct the noise measurements atthe control site locations on the bridge’s western sidewalk. The metric employed was the Larson-DavisMxSpect. The Model 2800 was field-calibrated before noise monitoring using a Larson-Davis AcousticCalibrator Model CAL25O. The microphone was located 7 m north of the transverse centerline of thesouth bound portion of each MEJ. The microphone was held approximately 1.5 m above sidewalk levelalong the CRB adjacent to the western sidewalk. Tire/MEJ interaction noise events (“croaks”) werecaptured and stored for vehicles using the south bound middle lane only.

A Bruel & Kjr Hand-held Analyzer (RHA) Type 2250 was employed for continuous noise monitoring atSite 2. This digital instrument corriplies with ANSI S1.4 [19831 standards for Type 1 Sound Level Metersand is capable of sampling the ambient sound level many times per second and storing the resultingsound level data for subsequent analysis and display. The Type 2250 was set to store the maximumsound level, or LAFm,,2. A time interval of 1 second was chosen to capture and isolate each individual“croak”3. The LAFmax(1 sec) and other metrics notably the L(1 sec)4were logged by the Type 2250. TheType 2250 was field-calibrated before noise monitoring using a Larson-Davis Acoustic Calibrator ModelCAL25O. The microphone was located near the walking trail in the southeast corner of the meadowadjacent Wildwood Crescent S. The microphone was mounted in a bush at a height of 1.5 m above localground level. This location had line-of-sight to the NAV and M6 MEJ’s.

In addition, the Type 2250 recorded the audio track at the Wildwood location for subsequentidentification of residual “croaks”. To insure that the residual “croaks” would be audible over thebackground, it was necessary to conduct the monitoring at Site 2 during the quietest portion of thenighttime, i.e. between 02:39 and 03:06 hours on April 9, 2015. The number of nighttime tire/MEJinteraction noise evnts during this time was limited. Any reasonably clean event was included in theaverage, provided it was audible and higher than the levels attained in the second before and after theevent.

1 When the MxSpec is selected on the Model 2800, a single one-third octave band spectrum (in dB) is logged at the instant ofdetection of the maximum energetic band summation occurring within the measurement interval. The MxSpec is normallyun-weighted. This metric has been employed for control site measurements at Golden Ears Bridge since March 2010.

LAF,,,, is the maximum, A-weighted, Fast Response, noise level attained over the measurement interval.The “croaks” are also known astire/MEJ interaction noise events.

L is the 90 percentile level. The La,, is the level that is exceeded 90% of the time. The L is considered a measure of thebackground noise level and is expressed in dBA.

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Golden Ears Bridge Modular Expansion Joint Noise April 27 2015Follow-Up Noise Measurement

Results

Control Sites la and lb

The results of the control site measurements are presented in Table 2.

Table 2: Noise Monitoring Results at the Control Sites

Before Geotextile/Neoprene Seals 5 years After Cieotextile/Neoprene Seals. June 20, 2011 April 9, 2015 NRSite Location

Summation of MxSpec Levels at Summation of MxSpec Levels at (dB)500, 630, 800 and 1 KHz (dB) 500, 630, 800 and 1 KHz (dB)

-7 m offset fromtransverse

la centerline (west 90.212 76.6 l3.6side) of the NAV

MEJ

-7 m offset fromtransverse

lb centerline (west 90.21.6 7g31

side) of the

M6MEJ

1. Arithmetic mean of 30 events.2. The standard deviation was 5 dB.3. Arithmetic mean of 90 events.4. The standard deviation was 2.5 dB.5. The noise reduction of the geotextile/neoprene seal treatment reported to HGC in March 26, 2013 was

NR 10.3 dB based on June 16 and 20, 2011 measurements.6. MxSpec average for the M6 MEJ have been approximated with the MxSpec average for the NAV since

MxSpec measurements were not conducted at M6 before the geotextile/neoprene seal treatment wasapplied.

The noise reduction (NR) provided by the geotextile/neoprene seal treatment is found by taking thedifference in the levels, averaged over 30 or more events, listed in the before and after columns of Table2. This results in 5th anniversary noise reductions of NR 13.6 dB and NR 11.9 dB for the NAV and M6M EJs respectively.

\Alwakefieldacoustics.com

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Golden Ears Bridge Modular Expansion Joint Noise April 27. 2U15Follow-Up Noise Measurement

Residential Site 2- Wfldwood Crescent S.

The results of the residential noise measurements conducted near Wildwood Crescent S. during thenighttime before and after the installation of the geotextile/neoprene seals are presented in Table 3.

Table 3: Noise Monitoring Results at Residential Site 2 (Wildwood)

Before Geotextile/Neoprene Seals 5 years After Geotextile/Neoprene SealsNRSite Location March 3, 2010 April 9, 2015 (dBLAF (dBA) LAF,, (dBA) Corrected for L

-565 m offset2 from the 58.02.3 47.4’ 1O.6

. NAVMEJ

1. Since the average residual “croak” levels 5 years after the treatment were LAF, 50.6 dBA and only 4.4dBA higher than the background L 46.2 dBA for the averaging period 02:39 to 03:06 it was deemednecessary to correct the measurements for background. Correcting the March 3, 2010 “croaks” forbackground was not necessary since they were approximately 10 dBA higher than the background.

2. Arithmetic mean of 30 events.3. The standard deviation was 3.2 dBA.4. The standard deviation was 2.8 dBA.5. The noise reduction of the geotextile/neoprene seal treatment reported to HGC in March 26, 2013 was

NR 7.7 to 8.7 dBA with a seasonal correction of 3 to 4 dBA applied to an uncorrected noise reduction ofNR 11.7 dBA based on the March 10, 2010 and August 30, 2011 measurements at Wildwood Crescent S.

The noise reduction provided by the geotextile/neoprene seals at residential Site 2 is again found bytaking the difference in the levels listed in the before and after columns of Table 2. This results in NR10.6 dBA for NAy, M6 MEJs. Occasionally the south tower MEJ was audible and approximately of thesame noise level as that of a typical M6 event.

Conclusions

The noise reduction effects of the geotextile/neoprene seals at -7 m offsets from the NAV and M6 MEJswere NR 13.6 dB and NR 11.9 dB respectively (vs NR 10.3 dB measured at the NAV MEJ in 2012) undersunny, dry and windless conditions and daytime temperature high of 15 degrees C.

The noise reduction at residential Site 2 for the same weather conditions was NR 10.6 dBA (vs NR 7.7 to8.7 dBA measured at the NAV 2012). Residual tire/MEJ interaction noise originated primarily from theNAV and M6 MEJ5 with minor contributions from the south tower MEJ.

It is concluded that over five years there was no loss in noise reduction performance of thegeotextile/neoprene seal treatments at NAV and M6 of the Golden Ears Bridge.

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Golden Ears Bridge Modular Expansion Joint Noise April 27, 2015

Foflow-Up Noise Measurement

trust this has provides the requfred information for the five year follow-up measurements of the NAVand M6 MEJs on the Golden Ears Bridge. Please call myself or Clair Wakefield at (250) 370-9302 if youhave any questions.

Sincerely,Wakefield Acoustics Ltd.

Duane Marriner, M.A.Sc., P. Eng.

Page 7 of 7wakefieldacoustics.com

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