GREEN LINE EXTENSION PROJECT

Transcription

1 GREEN LINE EXTENSION PROJECT RETAINING WALLS & NOISE BARRIERS

2 AGENDA Upcoming Meeting Schedule Wall Aesthetics/ Design FTA Guidelines for Assessing & Mitigating Noise Impact Plans & Cross Sections Typical GLX Real Estate Scenarios Preliminary Construction Phasing Breakout Session

3 Project Phasing LOWELL STREET

4 GLX Corridor Outreach Process: Retaining Walls/ Noise Walls Corridor-wide Overview May 22, 2012 Community/City-wide Meetings Neighborhood Meetings Jan/Feb 2014 Individual Property Owner Meetings Phase 1 Process Underway Phase 2/2A Process Just Beginning Phase 3 Process Underway Phase 4 Process Has Not Yet Begun

5 NEIGHBORHOOD PUBLIC MEETINGS Inner Belt/Brickbottom/Union Square Branch (includes Union Square Station) Wednesday, January 8, :00 8:00 PM Holiday Inn, 30 Washington Street, Somerville Washington Street to Medford Street (includes Washington Street Station) Tuesday, January 14, :00 8:00 PM Holiday Inn, 30 Washington Street, Somerville Medford Street to Lowell Street (includes Gilman Square Station) Wednesday, January 15, :00 8:00 PM Center for the Arts at the Armory 191 Highland Avenue, Somerville Lowell Street to Broadway(includes Lowell St. and Ball Square Stations) Wednesday, January 22, :00 8:00 PM Center for the Arts at the Armory 191 Highland Avenue, Somerville Glass Factory Condominiums Area (includes Lechmere Station) Tuesday, February 4, :00 8:00 PM Cambridge Multicultural Arts Center 41 Second Street, East Cambridge Broadway to Winthrop Street (includes College Avenue Station) Wednesday, February 5, :00 8:00 PM St. Clement School 579 Boston Avenue, Medford

6 Map of Neighborhood Meetings LOWELL STREET

7 Map of Neighborhood Meetings LOWELL STREET

8 Varying Conditions within GLX Corridor

9 GLX Corridor Walls Understanding of Multiple Perspectives From Green Line & Commuter Trains From the Backyards of Abutting Private Property From Bridges From the Future Community Path From Neighborhoods

10 GLX Corridor Walls Varying Considerations: Aesthetics Maintenance Graffiti Resistance Constructability Cost

11 GLX RETAINING WALLS & NOISE BARRIERS GOALS & OBJECTIVES Create functional & attractive systems to protect & enhance neighborhoods Design to be affordable, durable, high quality & constructible with minimum impact on abutters Meet or exceed state & federal requirements for noise attenuation Maintain some access to natural light where appropriate Develop wall finishes that discourage graffiti

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13 MBTA Orange Line

14 PHASE 1 HARVARD STREET WALL

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17 ACRYLIC TOP SOUND WALL DESIGN CRITERIA

18 NOISE BARRIER MAP LOWELL STREET

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20 FTA GUIDELINES FOR ASSESSING & MITIGATING NOISE IMPACT

21 FTA Guidelines for Assessing Noise Impact Noise impact is assessed by comparing existing noise levels to potential future increases in noise Future noise levels take into account: Number of total train events Whether events occur during the day or night Noise level of each train event Duration of each train event Existing noise levels are generally 65 to 80 Ldn Prior to mitigation, noise conditions would generally increase: A few decibels where there are existing commuter trains Approximately 10 db in areas where there are no existing commuter trains

22 FTA Guidelines for Mitigating Noise Impact Noise barriers are the preferred means of noise mitigation where feasible and effective Noise barrier design goals are to: Reduce noise 5 db or more Reduce levels below severe criteria Block the line of sight from significant train noise sources Future noise levels are expected to be lower than existing noise levels with the noise barriers at most locations along the existing commuter lines

23 TO CEDAR STREET LOWELL STREET

24 LOWELL STREET TO CEDAR STREET WALL CROSS SECTION

25 CEDAR STREET LOWELL STREET

26 CEDAR STREET LOWELL STREET

27 NORTH OF BROADWAY WALL CROSS SECTION

28 NORTH OF BROADWAY WALL CROSS SECTION Looking South Towards Ball Square Station and Broadway

29 TYPICAL GLX REAL ESTATE SCENARIOS

30 SCENARIO 1: NO EASEMENT REQUIRED LOWELL STREET

31 SCENARIO 2: TEMPORARY CONSTRUCTION EASEMENT REQUIRED

32 Example at Phase 1

33 SCENARIO 3: TEMPORARY/ PERMANANT CONSTRUCTION EASEMENTS REQUIRED LOWELL STREET

34 SCENARIO 4: TEMPORARY CONSTRUCTION EASEMENT/ PARTIAL FEE ACQUISITION REQUIRED

35 PRELIMINARY CONSTRUCTION PHASING

36 NEXT STEPS Survey Continuing Constructability Analysis Ongoing Geotechnical Work Ongoing Coordination with Drainage and Utilities is Ongoing Phase 2/2A Design Advancing to 60% Construction Documents Winter % Design of 2/2A Summer 2014 Phase 2/2A Early Construction Packages Summer 2014 Preconstruction Survey

37 BREAKOUT SESSION Lowell Street to Broadway

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