Vision Line Coalition Bellevue LRT Alignment Assessment Phase A Report
Document ref REP/210740/C001
FINAL 2
Vision Line Coalition Bellevue LRT Alignment Assessment Phase A Report High Level Alignment Investigation
September 2009
Arup North America Ltd 560 Mission Street, Suite 700, San Francisco, CA 94105 Tel +1 415 957 9445 Fax +1 415 957 9096 www.arup.com
This report takes into account the particular instructions and requirements of our client. It is not intended for and should not be relied upon by any third party and no responsibility is undertaken to any third party
Job number
210740
Document Verification
Page 1 of 1
Job title
Bellevue LRT Alignment Assessment
Job number
210740
Document title
Phase A Report
File reference
Document ref Revision Date
REP/210740/C001
Filename Description
Draft 1
09/09/09
First draft
Prepared by Name Signature
Checked by
Approved by
Eugene Lam
David Hunt / Nicholas Taylor
Richard Prust
Final 1
28/09/09
Filename Description
Bellevue LRT - Phase A Report (2009-09-23).doc Client comments incorporated
Prepared by Name Signature
Checked by
Approved by
Nicholas Taylor
Eugene Lam
Nicholas Taylor
Final 2
29/09/09
Filename Description
Bellevue LRT - Phase A Report (2009-09-29).doc Client comments incorporated.
Prepared by Name Signature Filename Description
Checked by
Approved by
Nicholas Taylor
Nicholas Taylor
Nicholas Taylor
Prepared by Name Signature
Checked by
Approved by
Issue Document Verification with Document
S:\00 PROJECTS\210740-00 BELLEVUE ALIGNMENT STUDY\4 INTERNAL PROJECT DATA\4-05 REPORTS & NARRATIVES\PHASE A REPORT - FINAL 2\BELLEVUE LRT - PHASE A REPORT (2009-09-29).DOC REP/210740/C001
Arup North America Ltd Final 2 29 September 2009
Vision Line Coalition
Bellevue LRT Alignment Assessment Phase A Report
Contents
1 Overview of Study and Phase A Scope 1.1 2 3 Key Meetings and Background Documents Page 1 1 1 2 2 3 3 3 3 4
th
VLC Alternative Alignment Alignment Description & Issues 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Design standards Southern Segment Wilburton Park & Ride Station Wilburton Park & Ride to NE 4th Street East Main Street Station NE 6 Street Station NE 4 Street to NE 8 Street Hospital Station and Northern Tie-In
th th
4 4 5 6
4 5
Conclusions Next Steps
Figures
Figure 1 - Downtown Bellevue Alignment Alternatives (DEIS) Figure 2 - South Bellevue Alignment Alternatives (DEIS) Figure 3 - Overall Map Figure 4 - Alignment Figure 5 - Alignment
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Arup North America Ltd Final 2 29 September 2009
Vision Line Coalition
Bellevue LRT Alignment Assessment Phase A Report
1
Overview of Study and Phase A Scope
Sound Transit is moving forward on the next phase of its regional transit strategy. The East Link Project is a major component of this effort which will link Seattle to Mercer Island, Bellevue, and Redmond with light rail transit (LRT) service via the I-90 corridor. The Draft Environmental Impact Statement (DEIS) was released for the East Link Project in late 2008. Subsequently, the Sound Transit Board identified two of the original six DEIS alignments as preferred alignments through Downtown Bellevue: a tunnel option (Alternative C3T) along 108th Avenue NE; and an at-grade couplet (Alternative C4A) along 108th and 110th Avenue NE. The Downtown Bellevue section (Segment C) ties into the South Bellevue section (Segment B) to the south and Bel-Red/Overlake (Segment D) section to the east. These options are illustrated in Figure 1 and Figure 2. Arup has been commissioned by the Vision Line Coalition (VLC) to assess an alternate alignment corridor (called the “VLC Alternative”) which differs from the six DEIS alternatives in Segment C. The VLC Alternative assessment was divided into three phases as follows:
• • •
Phase A - High-Level Alignment Investigation Phase B - Additional Investigation of Proposed VLC Alignment Phase C - Engineering Investigation of Proposed VLC Alignment
The scope of each Phase is described in the Arup proposal to the Vision Line Coalition dated August 2009. This report summarizes Arup’s findings for Phase A, which includes a high-level assessment of the proposed routing of the VLC Alignment. The Phase A study does not include assessment of existing utilities, construction staging, ridership, station planning etc.
1.1
Key Meetings and Background Documents
Meetings were held with key stakeholders and agencies, these included the following meetings: Date 26-Aug-09 Agency/Stakeholder Sound Transit Attendees Don Billen ( Sound Transit), John Sleavin (Sound Transit), Tony Raben (Sound Transit), Sue Comis (Sound Transit), Jason Bailey, Civil Engineer (Sound Transit), Nicholas Taylor (Arup) Denise Cieri (WSDOT), Wendy Taylor (WSDOT Consultant), Kevin Wallace (VLC), Nicholas Taylor (Arup)
1-Sep-09
WSDOT
Relevant documents and reports used to support the alignment analysis included the following: • • East Link Light Rail Draft Environmental Impact Statement (DEIS) WSDOT I-405 Corridor Program Master Plan
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Bellevue LRT Alignment Assessment Phase A Report
• •
Sound Transit Design Criteria (Chapter 4 – Track Alignment and Vehicle Clearances) GIS Aerial Mapping and Associated Files (City of Bellevue)
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2
VLC Alternative Alignment
The VLC proposal comprises an elevated alignment which follows the DEIS proposed B7 alignment to Main Street, and then follows the west side of I-405 between SE 8th Street and NE 6th Street, where the alignment crosses I-405 and links up with the DEIS proposed Hospital Station. The proposed alignment and station locations are shown in Figure 3. The VLC alignment includes the following elements:
•
Within Segment B in South Bellevue, the B7 alternative would be modified by moving the 118th SE Station north to the Wilburton Park & Ride. From B7, this proposed alignment would then generally follow the C8E alignment to south of 2nd Street, where it would proceed northbound largely along 114th Ave NE. An elevated station located at NE 6th Street and 114th Ave NE. From 6th Street, it would cross I-405 to connect to the BNSF corridor at the proposed Hospital Station.
•
• •
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Bellevue LRT Alignment Assessment Phase A Report
3
Alignment Description & Issues
The following section describes the VLC from south to north, highlighting key features and potential issues. Figure 4 and Figure 5 illustrate the proposed Vision Line Coalition alignment in the downtown area. 3.1 Design standards
The design standards being used in constructing these two alignments are from Chapter 4, Track Alignment and Vehicle Clearances, of Sound Transit’s Design Criteria, dated May 2009. Below are highlights of the key design criteria used in constructing the alignment along with the design interpretation used in preparing the conceptual VLC alignment.
Design Criteria Tangent Length
Sound Transit Criteria Desire Min = 200 feet Minimum = 100 feet Absolute Min = 40 feet
Design Interpretations Tangent lengths of 50 feet are used as a minimum
Tangent Beyond Platform
Desire Min = 75 feet Minimum = 60 feet Absolute Min = 45 feet
A 60 foot tangent beyond the ends of platforms is used.
Minimum Radius
Aerial Structures = 500 feet At-grade Ballasted = 300 feet
These minimum radii shall be respected. Grades of less than 4% are used.
Maximum Grades
Sustained Grade (unlimited length) = 4% Sustained Grade (up to 2500 feet) = 6% Short Sustained Grade (up to 500 feet) = 7%
Minimum Vertical Clearance at Overhead Bridges
Preferred Min = 21 feet 6 inches Desired Min = 15 feet 0 inches Absolute Min = 14 feet 7 inches
There are no overhead bridges within the study area.
Track Spacing Centerline to Centerline
Absolute Min = 12 ft (no center OCS poles) Absolute Min = 14 ft (center OCS poles) 16 ft apart at-grade. 8ft from center ROW 36ft.
16 foot adopted throughout.
Clearance Centerline to ROW
8 ft from centerline
The following station dimensions were derived from interpretation of the Sound Transit DEIS documents.
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Bellevue LRT Alignment Assessment Phase A Report
Center platform
30ft x 380ft central platform Track spacing 40ft centerline to centerline
Typical station footprint box interpreted by Arup as 60ft x 380ft
Side platform
13’4” x 380ft side platforms Track spacing 16ft centerline to centerline
Typical station footprint box interpreted by Arup as 60ft x 380ft
At this stage the alignment options proposed are strictly for light rail vehicles in the Sound Transit Link system. The option to operate DMUs on these alignments has not been assessed pending receipt of vehicle performance information. This will be considered during Phase B of this study.
3.2
Southern Segment
South of the downtown area the southern segment begins at Interstate 90 and ends to the south of the 118th Avenue Station following the preliminary design of Alternative B7 from the DEIS document. 3.3 Wilburton Park & Ride Station
The VLC alignment proposes to move the 118th SE Station northwards from the DEIS location to a location at the Wilburton Park & Ride. The alignment in this area is flexible and can accommodate a station at either location with minor adjustments. These adjustments to the alignment will not adversely impact other parts of the alignment. The proposed station at Wilburton Park & Ride will be elevated and will have a design similar to the 118th SE Station described in the DEIS. 3.4 Wilburton Park & Ride to NE 4th Street
Heading north from Wilburton Park & Ride, the VLC alignment follows 114th Avenue until reaching NE 4th Street. The alignment remains on an elevated structure to cross the existing Main Street and NE 4th Street bridge structures. These two bridges are currently constructed at about 25 feet above the elevation of 114th Avenue. In order for the light rail tracks to cross both the interstate and the local streets, it would require the structure to be built approximately 25 feet above the bridges. This would put the track elevation approximately 50 feet above the surrounding ground. The interstate expansion described in the I-405 Corridor Program Master Plan would not be impacted in this section. 3.5 East Main Street Station
A proposed East Main Street Station was identified in Option C8E of the DEIS document situated between Wilburton Park & Ride and NE 6th Street. VLC has recommended eliminating this station due to its proximity to the proposed Wilburton Park & Ride and NE 6th Street Stations.
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3.6
NE 6th Street Station
The VLC alignment proposes that a station be located between NE 4th and NE 6th Street. This station will be elevated to accommodate the approximately 50ft elevated track alignment. 3.7 NE 4th Street to NE 8th Street
North of NE 4th Street, the alignment turns east to cross I-405 and then north, crossing over four buildings to tie into the BNSF right-of-way and the proposed Hospital Station. This would result in a curved overcrossing with a significant span which will require further assessment, but which appears feasible given the available information. The alignment will make these turns between NE 6th Street and NE 8th Street. Vertically, this option is already 25-30 feet above the 6th Street bridge. Therefore clearing the interstate, 116th Ave and NE 8th Street will not be an issue. Other than the co-ordination required to locate the supporting columns to span the existing and planned configuration of I-405, the VLC alignment will not adversely impact the I-405 Corridor Program Master Plan. 3.8 Hospital Station and Northern Tie-In
The Hospital Station is located after the northerly turn after crossing the interstate. The station is elevated similar to the station design depicted in Alternative C1T and C2T from the DEIS. This northerly turn on the VLC elevated alignment requires the station to be shifted slightly to the north by approximately 200 feet. The tie-in to at-grade operations in the BNSF corridor will have a similar configuration to the designs detailed for Alternatives C1T and C2T from the DEIS.
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Vision Line Coalition
Bellevue LRT Alignment Assessment Phase A Report
4
Conclusions
The Vision Line Coalition (VLC) alignment appears feasible. The VLC alignment can adequately tie into Segment B (South Bellevue) to the south and Segment D (Bel-Red/Overlake) to the north. Key conclusions, impacts and findings for the VLC alternative are detailed below:
•
The proposed alignment will have minimal physical impacts on existing and planned infrastructure, including the build-out of the I-405 Corridor Program Master Plan. A tall elevated structure alongside the frontage of I-405 (and rear of 114th) is required. The relative height of this structure will be of the order of a four-story building. The visual, acoustic and aesthetic impacts of this structure in an urban setting will need to be assessed, but is similar to the elevated solutions proposed by Sound Transit. Mitigation of noise impacts from the elevated operations may be problematic for the surrounding and adjacent buildings. However the impacts would be expected to be similar to the elevated solutions proposed by Sound Transit. The acoustic impact of the VLC alignment is likely to be lower than the Sound Transit alternatives presented in the DEIS as: In Segment C, none of the adjacent existing buildings to the VLC alignment are residential, and The closer proximity of the VLC alignment to the I-405 corridor benefits from the enhanced noise masking effect of the I-405 corridor.
•
•
•
This option shifts the proposed Hospital Station to the north by approximately 200 feet.
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Bellevue LRT Alignment Assessment Phase A Report
5
Next Steps
This study has concluded that the VLC alignment is potentially viable. Therefore Arup recommends that the Vision Line Coalition further investigate the VLC alignment and proceed to the Phase B investigation to assess how the elevated alignment meshes with the planned development and growth of Bellevue, whether sufficient ridership can be attracted, and whether proposed operating plans can be implemented.
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FIGURES
Vision Line Coalition
Bellevue LRT Alignment Assessment Phase A Report
Figure 1 - Downtown Bellevue Alignment Alternatives (DEIS)
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Arup North America Ltd Final 2 29 September 2009
Vision Line Coalition
Bellevue LRT Alignment Assessment Phase A Report
Figure 2 - South Bellevue Alignment Alternatives (DEIS)
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Arup North America Ltd Final 2 29 September 2009