Ministry of Transportation and Infrastructure MEMORANDUM · December 2018, the Minister of...

Ministry of Transportation and Infrastructure

M E M O R A N D U M

Mailing Address:

PO Box 9850 Stn Prov Govt Victoria BC V8W 9T5

Telephone: 250 387-5062 Fax: 250 387-6431

Location: 5B 940 Blanshard Street Victoria BC V8W 3E6 www.gov.bc.ca/tran

January 6, 2020

George Massey Crossing Project Technical Analysis Summary and Next Steps

Purpose of this cover memo: This cover memo, prepared by the Ministry of Transportation and Infrastructure’s George

Massey Crossing Project Team, accompanies and provides context for the technical report

prepared by COWI/Stantec: Technical Services For George Massey Crossing Project (December 2019).

Purpose of the technical report: The attached technical report was prepared in support of the consultation with Metro

Vancouver’s George Massey Project Task Force and as reference material for discussions with

other parties.

This report does not make recommendations to the Ministry of Transportation and

Infrastructure, nor does it represent the extent of analysis that will be undertaken by the Ministry

to complete the business case for the George Massey Crossing Project.

Technical Work Program: The Ministry retained COWI/Stantec to provide technical services for the George Massey

Crossing Project in July 2019. COWI/Stantec’s primary task was to provide feasibility level

technical services and conceptual designs to support the work with Metro Vancouver Task

Forces, and to analyze potential options for the replacement of the existing George Massey

Tunnel under the Fraser River. The Ministry also used COWI/Stantec’s findings to support

discussions with participating First Nations, TransLink, adjacent Fraser River communities, and

key stakeholders.

COWI/Stantec developed and refined a range of technical work including traffic modelling and

analysis, structural and highway design, geotechnical and hydrotechnical analysis, preliminary

environmental review, and high-level cost estimating. COWI/Stantec also compared their

findings with the conclusions of the Independent Technical Review of the George Massey Crossing (Westmar Advisors 2018).

The results of COWI/Stantec’s work were summarized and compiled between November and

December 2019 to document the extent of the work conducted as well as the findings. The

Ministry notes the following with respect to the COWI/Stantec technical report:

• The level of traffic modelling and roadway design was sufficient to support a high-level comparison of options and related interchange connections, including proving the feasibility

of various crossing options. Additional modelling will be required, including micro-

simulations, to develop reference concepts for the business case.

• The scope of the environmental analysis was limited to confirming environmental indicators and a comparative risk assessment. Therefore, the Ministry also commissioned a separate,

more detailed environmental review of the options to support the multiple account

evaluation. The report, Environmental Input to GMC Multiple Accounts Evaluation (Hemmera 2019), is available under a separate cover. The extent of the environmental

analysis and mitigation will be prescribed by the Environmental Assessment Office once an

application is submitted for an Environmental Assessment Certificate.

• Order of magnitude cost estimates were developed to support the comparative analysis of options. More detailed cost estimates are now being developed to support business case

development in 2020.

Summary of Findings: While the purpose of the technical report was to support the Metro Vancouver Task Force in

selecting their preferred option, the Ministry’s Project team did draw the following conclusions

from the analysis:

• The relative cost, constructability, and environmental risk of a deep bored tunnel renders it unsuitable for consideration as a long-term solution for the George Massey Crossing.

• While the long- and short-term environmental effects of a long span cable bridge and an immersed tube tunnel differ, these effects can be managed through best practice

environmental offsets, and enhancements, which will be explored in more depth in the

coming months.

• Improving transit services and reliability remains a top priority for the new crossing. Expanding transit lanes on, and leading to, the new crossing will increase people-carrying

capacity across the Fraser River. This combined with TransLink’s potential support to

provide rapid transit service and increase transit frequency should increase ridership, and it

will also align with the region’s desired shift to sustainable modes.

• Dedicated pedestrian and cyclist facilities provide an important incentive for active transportation, and users are better served if these facilities are in/on the new crossing.

• The benefits of retaining the existing tunnel for traffic over the long term are limited. Additionally, the costs associated with seismic upgrades to retain the existing tunnel for this

purpose would be more expensive than the all-new infrastructure options. As such, the

existing tunnel should be retained for utilities only.

Actions and Next Steps: The Metro Vancouver Board’s decision to endorse an eight-lane immersed tube tunnel as Metro

Vancouver’s preferred solution for upcoming public engagement was based on the Metro

Vancouver Task Force’s discussions with the Ministry’s Project Team and the COWI/Stantec

analysis.

The Ministry will take the COWI/Stantec analysis and engagement with participating parties into

consideration when identifying a preferred option; however, additional technical analysis and

ongoing engagement with First Nations, federal, regional and municipal governments,

stakeholders, and the public remains to be completed in the coming months. The Ministry is in

the process of preparing a full business case by fall 2020.

DECEMBER 2019 BC MOTI

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT FINAL REPORT DRAFT 2019 DECEMBER 19

PROJECT NO. DOCUMENT NO.

A127810 GMC-rpt-01-gen-cowi_Final_report_Rev0E_19-Dec-2019

VERSION DATE OF ISSUE DESCRIPTION PREPARED CHECKED APPROVED

0E 19 December 2019

Final report draft Darryl Matson, P.Eng GMC – GMC Technical Lead

Derek Drummond GMC – Deputy Lead

Darryl Matson, P.Eng.

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT i

CONTENTS EXECUTIVE SUMMARY iii

Glossary of Terms xv

1 Introduction 1 1.1 Objectives 3 1.2 Report Organization 3

2 Technical Analysis and Design Process 5 2.1 Review of Long-List of Crossing Options 5 2.2 Short-List of Crossing Options 5 2.3 CST Presentation to Joint Agency Working Group 6 2.4 Short-List Option Refinement 6 2.5 COWI-Stantec Team Reporting 7

3 Technical Summary 8 3.1 CST's Technical Analysis of the Long-List of Options 8 3.2 COWI-Stantec Team's Technical Input to the Short-

List of Options 9 3.3 Summary of CST's Technical Findings for the Short-

List Options 26

4 References 49

APPENDICES Appendix A Continued Use of Existing Tunnel for Transit and Active

Transportation

Appendix B Deep Bored Tunnel

Appendix C Immersed Tube Tunnel

Appendix D Long-Span Bridge

Appendix E Geotechnical

ii GEORGE MASSEY CROSSING ASSESSMENT

Appendix F Environmental

Appendix G Hydrotechnical

Appendix H Traffic and Geometrics

Appendix I Examples of MUPs in Existing Tunnels

Appendix J Estimated Range of Total Project Cost for the Eight-Lane Options

Appendix K Renderings

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT iii

EXECUTIVE SUMMARY Introduction

The George Massey tunnel, constructed between 1957 and 1959, is a 630-meter long immersed tube tunnel (ITT) crossing the Fraser River (Figure EXEC1). The tunnel design was considered state-of-the-art, and among the first pre-fabricated rectangular concrete tunnels in the world to be installed using immersed tube technology.

Figure EXEC1: Typical Cross Section of the George Massey Tunnel as originally constructed (extracted from Westmar Advisors, 2018)

Now 60 years old, the existing tunnel does not meet current highway design or seismic standards. Plans to develop a replacement crossing were first announced in 2012, and in 2015 the Province released a project definition report and business case for a 10-lane cable-stayed bridge with interchange and highway improvements to be funded by user tolls.

In response to concerns about the proposed project size and tolling, the Province commissioned an Independent Technical Review (Westmar Advisors, 2018), which concluded that there are other, less costly options for a replacement that would be more in keeping with regional plans. In December 2018, the Minister of Transportation and Infrastructure (the Ministry) committed to work with Indigenous Groups, Metro Vancouver, TransLink, and Fraser River communities to develop a new crossing solution that better aligns with regional plans.

Working with these groups, in May 2019, the Ministry project team reached consensus on principles, goals and objectives, and developed a long-list of 18 potential crossing options for a new crossing. The Metro Vancouver Board also established a Task Force of elected officials to support the Province in identifying and evaluating crossing options.

iv GEORGE MASSEY CROSSING ASSESSMENT

In early July 2019, the Ministry hired COWI North America Ltd. (COWI) to provide feasibility level technical services and conceptual level design services to define the technical elements of different crossing options, which the Ministry would use to support its work in short-listing options, and ultimately in selecting a preferred option. Stantec is a primary subconsultant to COWI, and the COWI-Stantec Team (CST) is supported by several subconsultants. CST provided the following technical expertise and support to the Ministry:

› Bored tunnel engineering; › Immersed tube tunnel engineering; › Long span bridge engineering; › Highway design engineering; › Geotechnical engineering; › Travel demand forecasting; › High level transportation modeling; › Multi-modal transportation planning; › Traffic and safety engineering; › Review of existing tunnel; › Hydrotechnical engineering; › Environmental services; › Option review/refinement; › Renderings; and › Cost estimating.

The COWI-Stantec Team's work was completed between July and December 2019.

Objectives

The primary objectives of the COWI-Stantec Team's assignment were to:

› Provide recognized subject matter expertise for each of the technologies considered (deep bored tunnel, immersed tube tunnel and long span bridge);

› Complete factual and unbiased technical evaluations and conceptual level designs for the various crossing options; and,

› Prepare a detailed summary report of the work completed to support the future business case for a new crossing solution.

Technical Analysis and Design Process

Soon after the COWI-Stantec Team started on the project, the Ministry met with the Metro Vancouver Task Force, and reduced the long-list of eighteen options to a short-list of six options. As a result, CST's efforts primarily focused on the six short-list options which comprised the following:

› New eight-lane bored tunnel, plus MUPs in existing tunnel;

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT v

› New six-lane bored tunnel, plus two traffic lanes and multi-use paths (MUPs) in existing tunnel;

› New eight-lane immersed tube tunnel, plus MUPs in new or existing tunnel; › New six-lane immersed tube tunnel, plus two traffic lanes and MUPs in existing tunnel; › New eight-lane bridge with MUPs; and, › New six-lane bridge, plus two traffic lanes and MUPs in existing tunnel.

All six options included allocation of two lanes dedicated for transit (one in each direction).

The Project extent for CST's work included the crossing of the Fraser River, extending from the Steveston Interchange to the Highway 17A interchange. It is also noted that the Ministry is considering interim improvements at the Steveston Highway and Highway 17A interchanges and these improvements were incorporated in the design where applicable.

Given the importance of transit on the Highway 99 corridor, the Ministry asked CST to assess the expected transit travel time for each of the short-listed options. CST found that transit travel time would increase if the existing tunnel was used as a dedicated transit facility, primarily due to the added travel distance. Based on this assessment and discussions with TransLink and the Mayors Task Force, options that use the existing tunnel for vehicle traffic were dropped and the Ministry instructed the COWI-Stantec Team focus on the options with all eight lanes on the new structure.

Eight-Lane Deep Bored Tunnel (DBT)

The need to accommodate up to eight lanes of traffic resulted in a twin bore cross section with a stacked roadway arrangement (there would be two lanes on the top deck and two lanes on the bottom deck in each of the two bores). Given the depth and length of the DBT, pedestrian and cyclist traffic would be accommodated in the existing tunnel.

A cross section of the Eight-Lane DBT, including the existing tunnel use, is shown in Figure EXEC2.

Figure EXEC2: Cross Section of Deep Bored Tunnel Option (Including Existing Tunnel for MUPs)

vi GEORGE MASSEY CROSSING ASSESSMENT

Based on Ministry lane and shoulder width requirements, CST confirmed that an 18.5 m outside diameter bore would be required to accommodate four lanes of traffic and would be a world record if built (the current largest bored tunnel is the SR99 tunnel in Seattle, WA, which has a 17.5 m outside diameter).

Since the inside of the tunnel would be filled with air and the tunnel structure itself would be quite light, the DBT naturally wants to float. To prevent this, a significant amount of soil would be required on top of the tunnel. Therefore, the crown of the DBT would need to be approximately 60 m below the surface of the river. This results in a tunnel that would be approximately 4.4 km long (3.5 km between portals). Due to the length, the tunnel daylights past the Steveston Highway and Highway 17A interchanges, and therefore both interchanges would need to be replaced.

The entrance portals of the new tunnel were raised to an elevation of +4.38 m (approximately 2 m higher than the existing tunnel portals) to provide flood resiliency to the tunnel. It is possible that the Provincial Dike Authority may require additional height for this flood protection, but this could be accommodated readily if required.

A rendering of the twin bored, stacked roadway arrangement in the portal is shown in Figure EXEC3.

Figure EXEC3: Rendering of the Portal of the Eight-Lane Deep Bored Tunnel Option

There are several significant challenges associated with the DBT, including:

› Construction of the tunnel portals due to the depth needed for the Tunnel Boring Machines (TBM) to start boring.

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT vii

› The need to un-stack the traffic at each end, as well as the need to direct traffic into the correct lanes to allow vehicles to exit onto Steveston Highway and Highway 17A. Despite best efforts, CST could not identify an easy way to accomplish this; the only viable option identified involved moving the entrances/exits from Steveston and Highway 17A away from the current intersections by approximately 1 km each to allow the traffic to weave into the correct lanes (without this, one level of the bore would be significantly over loaded). This solution is not considered practical, however a better option was not identified.

› The significant impacts to lands in the Agricultural Land Reserve and increased trip times for all users.

› The risk of developing sink holes during construction, especially under the Fraser River. Based on a review of 100 tunneling projects around the world, it was found that, on average, one sink hole occurs for every 1.32 km of tunnel constructed.

› Since the existing tunnel would be used for Pedestrians and Cyclists, the seismic upgrade of the existing tunnel would need to be completed as part of the DBT option.

Eight-Lane Immersed Tube Tunnel (ITT)

In order to accommodate eight lanes and two MUPs, the ITT cross section would need to be approximately 47 m wide. The cross section is shown in Figure EXEC4.

Figure EXEC4: Cross Section of Eight-Lane Immersed Tube Tunnel Option

The significant span of the roof and floor in the eight-lane option would require the use of post-tensioned concrete construction or the use of a double steel sandwich plate construction. CST completed preliminary designs for both and determined that the post-tensioned concrete option would likely be the most economical option, and therefore this option was carried forward.

An upstream alignment for the new ITT was selected for a number of reasons, including: minimizing property impacts; reducing concerns of increasing scour at the existing downstream GVRD water tunnel; and avoiding impacting the location of a future relocation of the BC Hydro transmission line if required (which would be downstream of the existing tunnel).

The new tunnel would be approximately 1 km long and approximately 3 m deeper than the existing tunnel. The distance between the new tunnel and the existing tunnel was chosen to be 42 m to allow a sloped trench to be excavated for the new tunnel without destabilizing the existing tunnel.

viii GEORGE MASSEY CROSSING ASSESSMENT

The entrance portals of the new tunnel were raised to an elevation of +4.38 m (approximately 2 m higher than the existing tunnel portals) to provide flood resiliency to the tunnel. It is possible that the Provincial Dike Authority may require additional height for this flood protection, but this could be accommodated readily if required.

A rendering of the entrance portal to the new eight-lane ITT is shown in Figure EXEC5.

Figure EXEC5: Rendering of Eight-Lane ITT Option

In addition to the new ITT, the Deas Slough bridge would be replaced with a new bridge. The slough was filled in for the original construction, so the existing bridge is relatively short. CST has assumed that the slough would not be filled in for the new crossing, and this results in a bridge that would be approximately 310 m long. CST has assumed that the vertical clearance under the new Deas Slough bridge would be the same as the clearance under the existing bridge.

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT ix

Eight-Lane Long Span Bridge

The cross section of the main cable-stayed bridge would be approximately 43 m wide and is shown in Figure EXEC6.

Figure EXEC6: Cross Section of Eight-Lane Bridge Option

Similar to the ITT options, an upstream alignment was selected for the bridge options. Initial designs included a clear-span main section across the Fraser River to avoid in-river impacts, and approach spans with piers on either side including across Deas Slough (Option 1 shown in Figure EXEC7). A subsequent refinement was developed to also avoid piers in Deas Slough by adding a second cable-stayed span (Option 2 shown in Figure EXEC8).

Figure EXEC7: Rendering of Eight-Lane Bridge Option 1

x GEORGE MASSEY CROSSING ASSESSMENT

Figure EXEC8: Rendering of Eight-Lane Bridge Option 2

The distance between the edge of the bridge deck and the edge of the existing tunnel would be approximately 25 m. The clear span of the Fraser River crossing would be 650 m and the clear span of the Deas Slough crossing would be 380 m (Option 2).

The required shipping envelope was assumed to be the same as that required for the previous George Massey Tunnel Replacement project.

The Independent Technical Review (Westmar Advisors, December 2018) identified that cost savings could be achieved by shortening the cable-stayed bridge and placing the piers in the river. However, because the river piers would need to resist significant ship impact loads (assumed to be from a 60,000 DWT vessel), CST’s analysis determined that there would be little, or no cost savings associated with shortening the cable-stayed bridge.

Traffic Analysis

The COWI-Stantec Team performed macro Regional Traffic Modelling (RTM) to estimate the traffic volumes on the road network around and on the George Massey Crossing. The time horizons investigated were 2017 (the baseline date of the RTM model), 2035, and 2050. All scenarios included recent updates to regional demographic forecasts as well as planned transportation system expansions/improvements for the appropriate time frame.

Today, the George Massey Tunnel carries approximately 85,000 vehicles per day on average, approximately 10% of which are trucks. Additionally, transit represents approximately 1% of the vehicle trips, but carries approximately 10% of the people at the crossing. During the year, daily traffic can vary anywhere from 79,000 vehicles per day during the fall and winter periods to over 92,000 vehicles per day during the summer periods. During the morning and afternoon rush hour

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT xi

periods when the counter-flow lanes are in effect, the tunnel carries approximately 5,000 vehicles per hour in the peak direction and approximately 1,500 vehicles per hour in the off-peak direction. Current demands are between 4,800 and 5,400 vehicles per hour in the peak direction and between 2000 and 2500 vehicles per hour in the off-peak direction. Since the demands are at or above what the tunnel can process, weekday vehicle queues and corresponding delays for cars and commercial vehicles can be significant in both directions during the morning and afternoon three-hour periods.

During weekday midday and evening periods, as well as on weekends, when the tunnel supports two travel lanes in each direction, traffic volumes are slightly below the capacity of the two-lane crossing contributing to some moderate delays, particularly when heavy commercial vehicles are most prominent.

Table EXEC1 shows the forecast 2035 and 2050 demands (veh/hr) assuming an eight-lane crossing with three GP lanes and one dedicated bus lane in each direction, along with current estimated peak hour demand for reference. The forecast volumes are effectively the same for all three technologies (Deep Bored Tunnel, Immersed Tube Tunnel, and Bridge). As illustrated, traffic demand during rush hour is projected to increase over the next 30 years.

Table EXEC1 – Current and expected peak hour demands (veh/hr)

Time Period Direction Current Demand

(2017 model) 2035 GMC Demand 2050 GMC Demand

AM Peak Hour NB 4880 5300 5570 SB 2010 3280 3460

PM Peak Hour NB 2470 3820 4050 SB 5410 5960 6300

The planned eight-lane George Massey Crossing, including a dedicated bus-only lane in each direction, would support improved mobility for sustainable modes, goods movement as well as vehicular travel through:

• Dedicated bus-only lanes, which would support the existing two minute services in peak directions with increasing service levels and capacity through the introduction of double-decker buses over the next few years. Dedicated lanes would connect with bus-on-shoulder facilities both north and south of the existing crossing and would ultimately support increased ridership to/from South of Fraser communities;

• Dedicated pedestrian and cycling facilities between Richmond and Delta connecting into TransLink's Major Bike Network that serves urban centres across Metro Vancouver;

• Additional capacity serving off-peak directional travel as well as midday and weekend traffic, including commercial vehicles supporting regional, provincial and national trade corridors. The additional capacity for off-peak periods would be particularly important for summer periods when daily traffic is highest; and,

xii GEORGE MASSEY CROSSING ASSESSMENT

• Improved safety and incident management with active lane-management and improved responses.

The combination of removing buses from general traffic lanes, increased transit service, and moderate improvements in general purpose capacity due to wider travel lanes and improved safety would help improve travel time speed and reliability and reduce congestion. Continued improvement in transit service levels between South of Fraser and Richmond / Bridgeport Station also would be needed to further reduce congestion during these times, as is the case in other parts of the region, to provide attractive alternatives, manage demands and support regional and provincial goals for sustainable modes and climate action.

Additionally, improved utilization for the bus-only lanes could be considered through alternative lane designations (HOV/transit, auxiliary lanes) to avoid or minimize peak period queues in future. In this regard, technical strategies could be considered at subsequent stages of planning and design, to address some of the growth in vehicle queues while maintaining priorities for transit on the new crossing.

Estimated Costs

The COWI-Stantec Team developed estimated order of magnitude, total project costs for the eight-lane DBT, ITT, and Bridge options, which included construction cost, design cost, owner costs, property acquisition costs, environmental offsetting costs, escalation, interest during construction, and an allowance for risk and contingencies.

CST's estimated total project cost for each eight-lane option was as follows:

› Deep Bored Tunnel: between $12 and $17 billion.

› Immersed Tube Tunnel: between $4 and $5 billion.

› Bridge: between $3.5 and $4.5 billion.

The cost ranges allowed for relative comparisons between the various options as the project progressed but are not considered suitable for budgeting purposes.

Following the meeting the Ministry had with the Task Force on October 2, 2019, the Ministry requested that CST develop detailed project cost estimates for the eight-lane ITT option and the eight-lane Bridge option (for the purpose of the Bridge option, the Ministry requested that Option 2 be evaluated). These detailed cost estimates were not complete at the time of writing this report.

Estimated Design and Construction Schedule

The design schedule for all options is expected to be similar – all taking between one and two years. Depending on the procurement strategy, there is a possibility of overlapping the design schedule with the construction schedule (e.g. design-build or forms of early contractor involvement procurement methods).

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT xiii

The construction schedule for the options is expected to be as follows:

› Deep Bored Tunnel: approximately seven years (plus an extra year to seismically upgrade the existing tunnel after traffic is transferred to the new facility);

› Immersed Tube Tunnel: approximately five years (plus an extra year to close the portals of the existing tunnel and recommission it for utility only use); and,

› Bridge: approximately five years (plus an extra year to close the portals of the existing tunnel and recommission it for utility only use).

For the ITT options, work in the river is likely limited to a 6-month or 7-month work window each year. This imposes a schedule risk that would need to be considered since if the construction falls behind, critical path items could be delayed by 6 months, or even potentially a year.

TECHNICAL SERVICES FOR GEORGE MASSEY CROSSING PROJECT xv

Glossary of Terms ALR Agricultural Land Reserve

Assignment COWI's assignment to provide as-and-when technical services for the George Massey Crossing project. The assignment occurred in 2019.

CST The COWI-Stantec Team that completed the present assignment.

GMC George Massey Crossing

Project Activities related to the George Massey Crossing replacement. It includes preliminary studies, procurement process, design, and construction.

ITT Immersed Tube Tunnel

DBT Deep Bored Tunnel

GP Lane General Purpose Traffic Lane

RTM Regional Traffic Model

TBM Tunnel Boring Machine

GEORGE MASSEY CROSSING ASSESSMENT 1

1 Introduction

The George Massey tunnel, constructed between 1957 and 1959, is a 630-meter long immersed tube tunnel (ITT) crossing the Fraser River (Figure 1). The Tunnel design was considered state-of-the-art, and among the first pre-fabricated rectangular concrete tunnels in the world to be installed using immersed tube technology. The Province of British Columbia (the Province) owns and operates the Tunnel.

Figure 1: Typical Cross Section of the George Massey Tunnel as originally constructed (extracted from Westmar Advisors, 2018)

Now 60 years old, the existing tunnel does not meet current highway design or seismic standards. Plans to develop a replacement crossing were first announced in 2012, and in 2015 the Province released a project definition report and business case for a 10-lane cable-stayed bridge with interchange and highway improvements to be funded by user tolls.

In response to concerns about the proposed project size and tolling, the Province commissioned an Independent Technical Review (Westmar Advisors, 2018), which concluded that there are other, less costly options for a replacement that would be more in keeping with regional plans. In December 2018, the Minister of Transportation and Infrastructure (the Ministry) committed to work with Indigenous Groups, Metro Vancouver, TransLink, and Fraser River communities to develop a new crossing solution that better aligns with regional plans.

Working with these groups, in May 2019, the Ministry project team reached consensus on principles, goals and objectives, and developed a long-list of 18 potential crossing options for a new crossing. The Metro Vancouver Board also

2 GEORGE MASSEY CROSSING ASSESSMENT

established a Task Force of elected officials to support the Province in identifying and evaluating crossing options.

In early July 2019, the Ministry hired COWI North America Ltd. (COWI) to provide feasibility level technical services and conceptual level design to define the technical elements of different crossing options, which the Ministry would use to support its work in short-listing options, and ultimately in selecting a preferred option. Stantec is a primary subconsultant to COWI, and the COWI-Stantec Team (CST) is supported by several subconsultants. CST provided the following technical expertise and support to the Ministry:

› Bored tunnel engineering; › Immersed tube tunnel engineering; › Long span bridge engineering; › Highway design engineering; › Geotechnical engineering; › Travel demand forecasting; › High level transportation modeling; › Multi-modal transportation planning; › Traffic and safety engineering; › Review existing tunnel and risk assessment reports and findings; › Hydrotechnical engineering; › Environmental services; › Option review/refinement; › Renderings; and › Preliminary cost estimating.

Responsibilities of the CST team members are outlined in Table 1.

Table 1 – Key team members and their specialties

Consultant Area of Responsibility

COWI North America Ltd. › Lead Consultant

› Project Technical Lead

› Bridge Lead

› Immersed Tube Tunnel Lead

› Renderings and animations

Stantec Consulting Ltd. › Deputy Lead

› Highway Design Lead

› Geotechnical Lead

› Environmental Lead

› Multi-Modal Lead

› Traffic engineering support


Consultant Area of Responsibility

› Project management

McMillen Jacobs Canada Corporation › Bored Tunnel Lead

Great Northern Engineering Consultants Inc.

› Traffic Lead

McElhanney Ltd. › Traffic modelling

Northwest Hydraulic Consultants Ltd. › River hydraulics

Anthony Steadman And Associates Inc. › Detailed cost estimating

MMK Consulting Inc. › Multiple Account Evaluation

Naesgaard-Amini Geotechnical Ltd. › Geotechnical Support

1.1 Objectives The primary objectives of the COWI-Stantec Team's assignment were to:

› Provide recognized subject matter expertise for each of the technologies considered (deep bored tunnel, immersed tube tunnel and long span bridge);

› Complete factual and unbiased technical evaluations and conceptual level designs for the various crossing options; and,

› Prepare a detailed summary report of the work completed to support the future business case for a new crossing solution.

This report summarizes the process and results of CST’s technical work.

1.2 Report Organization This report is divided into three chapters and supporting appendices as follows:

› Chapter 1 presents the background for the assignment;

› Chapter 2 presents the technical analysis and design process and a description of the tasks performed by CST;


› Chapter 3 presents the main findings of the technical work performed; and,

› The appendices contain technical memos summarizing the work performed by CST and additional background information.


2 Technical Analysis and Design Process The COWI-Stantec Team's work for this report was completed between July and December 2019.

2.1 Review of Long-List of Crossing Options In July 2019, CST provided a high-level analysis of technical feasibility of the long-list of 18 options, including reviewing existing information, estimating high-level construction costs and developing preliminary road alignments for bored tunnel, immersed tube tunnel, and bridge options. The Ministry used this information to support development of its July 2019 meeting with the Metro Vancouver Task Force. As an outcome of this meeting, the long-list of options was refined to a short-list of six options:

› New eight-lane bored tunnel, plus MUPs in existing tunnel; › New six-lane bored tunnel, plus two traffic lanes and multi-use paths (MUPs) in

existing tunnel; › New eight-lane immersed tube tunnel, plus MUPs in new or existing tunnel; › New six-lane immersed tube tunnel, plus two traffic lanes and MUPs in existing

tunnel; › New eight-lane bridge with MUPs; and, › New six-lane bridge, plus two traffic lanes and MUPs in existing tunnel.

All six options included allocation of two lanes dedicated for transit (one in each direction).

2.2 Short-List of Crossing Options CST was tasked to provide a high-level design for each of the short-listed crossing options and determine the related impacts to property and to the Steveston Highway interchange and Highway 17A interchange.

The Ministry also requested CST to confirm forecast traffic volumes for the short-listed crossing options using macro simulation modeling with the Regional Traffic Model (RTM).

Since some of the short-listed options included re-use of the existing tunnel for MUPs and/or transit only lanes, the Ministry asked CST to evaluate the implications of using the existing tunnel for this purpose.


2.3 CST Presentation to Joint Agency Staff Working Group

On August 8, 2019, the COWI-Stantec Team, along with the Ministry project team, presented preliminary technical findings to a joint agency staff working group comprising staff from the City of Delta, City of Richmond, Metro Vancouver, TransLink and Tsawwassen First Nation.

In attendance for CST were the Project Technical Lead, Bored Tunnel Lead, ITT Lead, and Bridge Lead to present CST’s initial findings including high level design of the six short-listed options and the primary risks associated with each technology. The information presented was technical in nature and intended to provide staff with early insight to the options analysis as input to their ongoing discussions with the Ministry. CST responded to technical questions at this meeting.

2.4 Short-List Option Refinement Following the meeting, CST continued to develop the technical scope of the short-listed options.

CST's design configuration of the Bored Tunnel options was significantly different than the Bored Tunnel option presented in the Independent Technical Review (Westmar Advisors, 2018). To confirm the validity of CST’s design the Ministry asked CST to obtain an independent review of the proposed depth of the Bored Tunnel, and an independent review of the risk of a sink hole during construction. These reviews confirmed CST’s design. Subsequently, the Ministry also confirmed CST’s Deep Bored Tunnel concept with the Independent Reviewer, Westmar Advisors.

Given the importance of transit on the Highway 99 corridor, the Ministry also asked CST to assess the expected transit travel time for each of the short-listed options. CST found that transit travel time would increase if the existing tunnel were to be used as a dedicated transit facility, primarily due to the added travel distance.

As CST’s technical work on the short-list of options continued, our team identified operational challenges specific to the Bored Tunnel options caused by the stacked traffic lane design. The solutions to these are described in more detail in Section 3.2.9.

As the ITT options developed, CST investigated the hydrotechnical issues associated with the in-river trenching needed for the tunnel. The preliminary hydrotechnical findings showed that the trench is feasible and should not present significant construction challenges.

CST also developed renderings for the eight-lane options for each of the Bored Tunnel, ITT, and Bridge technologies.


Finally, CST provided drawings, renderings and updated technical analysis as input to the following key meetings with the joint agency staff working group and the Task Force:

› Joint-agency staff working group (September 12, 2019) – technical update;

› Metro Vancouver Finance and Intergovernmental Committee (September 18, 2019) – the Ministry subsequently directed CST to stop work on the six-lane short-list options and only continue advancing the eight-lane options, including order of magnitude cost estimates for each; and,

› Task Force (October 2, 2019) – Task Force identified the eight-lane ITT as their preferred option for Metro Vancouver’s interests.

It is noted that this information was also used to support the Ministry’s on-going engagement with Indigenous Groups.

2.5 CST Reporting Following the October 2, 2019 Task Force meeting, the COWI-Stantec Team continued to respond to additional questions from the Ministry, including developing more accurate overall project cost estimates for the eight-lane ITT and eight-lane Bridge options. No further work for the eight-lane bored tunnel option was developed.

In addition, CST finalized this report and its appendices, summarizing our teams work.


3 Technical Summary This Chapter presents the main findings and technical information that the COWI-Stantec Team developed for the GMC options analysis. Background information and additional details are provided in Appendices as noted.

3.1 CST's Technical Analysis of the Long-List of Options

The following long-list of options was finalized in June 2019 prior to CST’s involvement:

Options that include the existing tunnel: 1. New four-lane bridge; keep existing four-lane tunnel (all general purpose [GP] lanes) 2. New four-lane deep bored tunnel; keep existing four-lane tunnel (all GP lanes) 3. New four-lane immersed tube tunnel; keep existing four-lane tunnel (all GP lanes) 4. New six-lane bridge (all GP lanes); keep existing tunnel for transit or local traffic 5. New six-lane deep bored tunnel (all GP lanes); keep existing tunnel for transit or local traffic 6. New six-lane immersed tube tunnel (all GP lanes); keep existing tunnel for transit or local traffic

Options without the existing tunnel:

7. New six-lane bridge (all GP lanes); with counterflow 8. New six-lane deep bored tunnel (all GP lanes); with counterflow 9. New six-lane immersed tube tunnel (all GP lanes); with counterflow 10. New six-lane bridge (all GP lanes); without counterflow 11. New six-lane deep bored tunnel (all GP lanes); without counterflow 12. New six-lane immersed tube tunnel (all GP lanes); without counterflow 13. New seven-lane crossing; with counterflow (assume all GP but consider a peak direction-only transit lane) 14. New seven-lane deep bored tunnel; with counterflow (assume all GP but consider a peak direction-only transit lane) 15. New seven-lane immersed tube tunnel; with counterflow (assume all GP but consider a peak direction-only transit lane) 16. New eight-lane bridge; consider potential dedicated lanes 17. New eight-lane deep bored tunnel; consider potential dedicated lanes 18. New eight-lane immersed tube tunnel; consider potential dedicated lanes


All options assumed that MUPs would be provided across the Fraser River and that the existing tunnel would continue to be used as a utility corridor.

Within the first few days of starting the assignment, CST conducted a workshop to develop an initial draft Multiple Account Evaluation for the long-list of options, based on the project goals and objectives established by the Ministry in consultation with participating agencies and interest groups. A working draft of CST's findings was provided to the Ministry on July 17, 2019 as input for its meeting with the Task Force, however since the Task Force short-listed to six options at this meeting, the Ministry halted any further work on the evaluation of the long-list of options. Key findings of CST's initial evaluation are noted below:

› Options that relied on the existing tunnel for regular GP traffic lanes did not improve safety significantly.

› The bridge options could move forward more quickly than the tunnel options.

› The ITT options would have the greatest impact on the river in the short term, but the least long-term impact.

3.2 CST's Technical Input to the Short-List of Options

The short-listed options considered by CST were as follows:

› Option A – Eight-Lane Bored Tunnel: six GP lanes and two dedicated transit lanes in a new Bored Tunnel, with a bi-directional MUP in the existing tunnel.

› Option B –Six-Lane Bored Tunnel: six GP lanes in a new Bored Tunnel, with two dedicated transit lanes and a bi-directional MUP in the existing tunnel.

› Option C –Eight-Lane Immersed Tube Tunnel: six GP lanes, two MUPs and two dedicated transit lanes in a new ITT.

› Option D – Six-Lane Immersed Tube Tunnel: six GP lanes and two MUPs in a new Immersed Tube Tunnel, with two dedicated transit lanes in the existing tunnel.

› Option E – Eight-Lane Bridge: six GP lanes, two MUPs and two dedicated transit lanes on a new Bridge.

› Option F – Six-Lane Bridge: six GP lanes and two MUPs on a new Bridge, with two dedicated transit lanes in the Existing Tunnel.


The Project extent for CST's work included the crossing of the Fraser River, extending from the Steveston Interchange to the Highway 17A interchange. It is however noted that the Ministry is considering interim improvements at the Steveston Highway and Highway 17A interchanges and these improvements were incorporated in the design where applicable.

Concepts were developed such that, where practical, precedent projects elsewhere in the world could be used as viable references. CST accomplished this goal for all options except the eight-lane Bored Tunnel, which in order to fit the lanes and the necessary shoulders, would require a bore with an outside diameter of approximately 18.5 m, 1 m larger than the world’s largest bored tunnel at the time of its construction (Bertha in Seattle, USA).

3.2.1 Major Design Criteria Components It was important that CST's work resulted in an unbiased assessment of all alternatives. Therefore, one of CST’s first tasks was to develop a consistent set of design criteria for the GMC. These criteria were applied uniformly across all options.

Following is a list of the key design criteria applied to each option that CST investigated.

› Highway design: Meet requirements of TAC and BC Supplement to TAC

› Design speed for Highway 99: 100 km/h

› Transit lane width on new bridge/tunnel: 3.7 m

› General purpose (GP) lane width: 3.7 m

› Shoulder widths on new bridges and in new tunnels:

Number of Lanes Inside Shoulder Outside Shoulder

1 lane roadway 1.0 m 2.5 m 2 lane roadway 1.0 m 2.5 m 3 lane roadway 1.0 m 1.5 m 4 lane roadway 1.0 m 1.0 m

› Shoulder widths on Roadway: Inside shoulder 1.7 m; outside shoulder 3.0 m

› Multi Use Path width: 3.5 m (it is noted that while some initial design drawings applied a more standard with of 3.0 m, a 3.5 m MUP width was


subsequently confirmed to be feasible and is the width reflected in CST’s final cost estimates).

› Vehicle vertical clearance: 5.0 m (roadway); 3.5 m (MUPs)

› Maximum roadway grade: 5%

› Seismic Criteria: Existing tunnel classified as "Other" structure; therefore, upgraded to 1:475 year design earthquake. All new facilities classified as "Lifeline" structures; therefore, designed to resist a 1:2,475 year design earthquake.

› Navigation clearance envelope: Elevation -15 m (Geodetic) deep by 325 m wide underwater; 59.57 m clearance from high water (2.0m Geodetic) for the one-way shipping channel; 57.0 m clearance from high water for the two-way shipping channel; and 53.8 m clearance from high water for the indicative nautical clearance safety zones.

› Design Life of new tunnel or new bridge: 120 years

› Fire Life Safety: NFPA 502 Category D (Tunnels)

› Dangerous goods movement: Allowed on new facility, not allowed in the existing tunnel.

3.2.2 Continued Use of Existing Tunnel for Transit and Active Transportation

CST reviewed the original design of the existing tunnel, as well as retrofits that have been done, as well as previous studies of the existing tunnel. Based on this background information, CST concluded that it would be possible to use the existing tunnel for transit, MUPs, or only utilities as part of the GMC project.

Since the seismic upgrade of the existing tunnel has only been partially completed for the tunnel, if the existing tunnel is used for transit or MUPs as part of the future GMC, the seismic upgrade would need to be completed, both, structural upgrades and ground improvement within the river channel and on land. Also, if the existing tunnel is used for MUPs, it is expected that lighting upgrades would also be required.

For the six-lane options, the existing tunnel would be used for the transit only lanes. CST's traffic analysis of transit use in the existing tunnel indicated increased trip times for buses compared to the eight-lane options. This was not considered acceptable by TransLink and was a significant factor in eliminating the six-lane options.


More detail of CST's evaluation of the existing tunnel is given in Appendix A.

3.2.3 Deep Bored Tunnel (DBT) The need to accommodate up to eight lanes of traffic resulted in a twin tunnel cross section with a stacked roadway arrangement (e.g. for the eight-lane DBT option, there would be two lanes on the top deck and two lanes on the bottom deck in each of the two bores). A rendering of the twin bored, stacked roadway arrangement in the portal is shown in Figure 2.

CST’s mandate was to work within proven reference designs from around the world; this proved to be difficult for the eight-lane DBT option. Based on Ministry lane and shoulder width requirements, CST confirmed that an 18.5 m outside diameter bore would be required to accommodate four lanes of traffic (and a slightly smaller bore with a 17.5 m outside diameter for three lanes of traffic). Given the depth and length of the DBT, pedestrian and cyclist traffic would be accommodated in the existing tunnel for both DBT options.

Figure 2: Rendering of Eight-Lane Deep Bored Tunnel Option (see Appendix K for additional renderings)

The vertical geometry and specifically the depth of the DBT under the river was a significant factor in the layout of this option. The primary design requirement that dictated the depth of the DBT was the buoyancy resistance. Since the inside of the tunnel would be filled with air and the tunnel structure itself would be quite light, the DBT would naturally float. To prevent this, a significant amount of soil on top of the tunnel would be required. The governing location for this is under the Fraser River and Deas Slough. In both locations, soils to elevation -35 m is made up of loose to compact sands, which are susceptible to liquefaction during the design earthquake, and would provide no buoyancy resistance during an earthquake.


CST’s geotechnical evaluation confirmed that under the river, the crown of the DBT would need to be placed at elevation -45 m (approximately 1.5 bore diameters deep) if the sand layer is improved (densified) to elevation -35 m; or at elevation -60 m (approximately 2.5 bore diameters deep) to avoid ground improvements.

› Both options would require full replacement of the Steveston Highway and Highway 17A interchanges, and both have similar impacts to agricultural lands.

› The shallow option would result in a tunnel length of approximately 2900 m. It would require soil improvement for the full length of the tunnel and portals, including in the river, to provide buoyancy resistance. In addition, it would require a layer of rip rap, approximately 2 m thick, to be placed on the river bed above both tunnels, requiring significant dredging to ensure that the rip rap was below the underwater navigation clearance envelope.

› The deeper option would result in a tunnel length of approximately 3500 m and would require soil improvement only when the crown of the tunnel rises above elevation -60m (approximately 600 m at each end of the tunnel plus under the portals).

Since the main advantage of the deep bored tunnel option was the ability to not disturb the river, the shallower DBT option was not carried forward by CST.

Therefore, the DBT length for both the six-lane and eight-lane options would be approximately 3.5 km long and would have a total roadway length of approximately 4.5 km between the tie-in points to Highway 99. The entrances/exits of the DBT would be north of Steveston Highway and south of Highway 17A. The resulting roadway configuration to tie back to the interchanges at Steveston Highway and Highway 17A would result in significant impacts to lands in the Agricultural Land Reserve and increased trip times for all users. Given the significance of these impacts and that these impacts were driven by the depth of the tunnel under the river, the Ministry requested that CST undertake an independent check of the tunnel depth. The results of this independent check confirmed that CST’s depth assumptions were correct. A memo to this effect is included in Appendix B.

Construction of the tunnel portals present a significant challenge. The Tunnel Boring Machines (TBM) need to start boring in a launching pit. The bottom of the launching pit would need to be at approximately elevation -37 m to mitigate issues associated with buoyancy of the first segments of the tunnel. Adding to the complication of the portal construction is that the excavation would need to be maintained in a dry state, therefore requiring extensive dewatering. Recent reported construction experience in Richmond is that the deepest de-watered excavations are in the order of 10 m deep, much smaller than would be required for the DBT launching pit. The depth of the launching pits would result in very expensive excavations and dewatering at each end of the DBT. Taking into consideration these significant


challenges, CST prepared a conceptual design for the launching pits in order to develop a cost estimate.

The shape of the bore (a circle) results in the need to stack the traffic in each bore (two lanes on a top deck and one or two lanes on a bottom deck). This presented significant challenges, both to “unstack” the traffic at each end, as well as the need to direct traffic into the correct lanes to allow vehicles to exit onto Steveston Highway and Highway 17A. The stacking and unstacking could be accomplished in the length of the portals; however, getting the traffic in and out of the correct lanes proved to be challenging. Despite best efforts, CST could not identify an easy way to accomplish this; the only viable option identified involved moving the entrances/exits from Steveston and Highway 17A away from the current intersections by approximately 1 km each to allow the traffic to weave into the correct lanes (without this, one level of the bore would be significantly over loaded). This solution is not considered practical, however a better option was not identified.

With bored tunnels, there is a risk of developing sink holes as the DBT mining progresses. During the boring operation, the front end of the TBM must be pressurized to prevent water from entering the tunnel. This is accomplished by using a pressured face TBM. For larger TBMs (i.e., larger than 10 m diameter), maintaining this balanced pressure is a significant challenge, and the risk of a sink hole developing increases. Given the significance of this risk, CST undertook a separate study regarding sink holes. Based on a review of 100 tunneling projects around the world, it was found that, on average, one sink hole occurs for every 1.32 km of tunnel constructed and that the formation of a sink hole in the Fraser River would be extremely difficult and expensive to remedy. Memos to this effect are included in Appendix B, along with more details of CSTs' technical work for the Deep Bored Tunnel options.

The portals of the new tunnel were raised to an elevation of +4.38 m to provide flood resiliency to the tunnel. This height allows for 1 m of future sea level rise due to climate change and would result in the roadway being approximately 2 m higher than the current entrance/exit of the tunnel. It is possible that the Provincial Dike Authority may require additional height for this flood protection, but this could be accommodated readily if required.

3.2.4 Immersed Tube Tunnel (ITT) The COWI-Stantec Team has extensive experience with ITT's around the world. Due to local ground conditions, and local depth and width requirements each ITT is unique. It was therefore not possible for CST to identify a similar ITT to that required for GMC to benchmark the size and cost. As such, CST expended considerable efforts to develop a fairly detailed concept level design for the ITT options to allow for a fair comparison with the bridge and DBT options.


Preliminary structural design was completed on both six-lane and eight-lane options. CST determined that the six-lane option could be built with conventional reinforced concrete tunnel technology because the tube width needed to carry three traffic lanes and shoulders is narrow enough that the concrete shell of the ITT could be designed for water tightness.

Figure 3: Rendering of Eight-Lane ITT Option (see Appendix K for additional renderings)

Based on CST's analysis, the eight-lane option could not be built with conventional reinforced concrete tunnel technology because the roadway tube width needed to carry four lanes of traffic and shoulders would be too wide. The significant span of the roof and floor in the eight-lane option would be too large to achieve crack control, and therefore water tightness, using simple reinforced concrete. As such, there are three possible solutions:

› Separate the carriageway into four two-lane roadways. This option was discarded since it increased the total tunnel width by almost 20%, and would result in a world record width for an ITT;

› Use post-tensioned concrete construction; or

› Use a double steel sandwich plate construction.

CST completed preliminary designs for the second and third options and determined that the post-tensioned concrete option would likely be the most economical option, and therefore this option was carried forward for costing purposes.

A rendering of the entrance portal to the new eight-lane ITT is shown in Figure 3.

An upstream alignment for the new ITT was selected for a number of reasons, including: minimizing property impacts; reducing concerns of increasing scour at the


existing downstream GVRD water tunnel; and avoiding impacting the location of a future relocation of the BC Hydro transmission line if required (which would be downstream of the existing tunnel).

CST investigated the minimum distance between the new tunnel and the existing tunnel. A 25 m distance between the two structures was studied in order to minimize property impacts. It was determined that this distance required an underwater retaining wall during construction so that excavating the trench for the new tunnel would not undermine the existing tunnel. This retaining wall was evaluated and was found to be excessively expensive and could add a year to the construction schedule. Without a retaining wall, the underwater excavation would need to be a cut slope. CST determined that the maximum slope during construction could be 2H:1V (horisontal:vertical). In order to be slightly conservative, CST used a 2.3H:1V cut slope between the new and existing tunnels, and a 3H:1V cut slope upstream of the new ITT. The 2.3H:1V was rounded up from 2.25H:1V, which was chosen such that the distance between the existing tunnel and the new ITT would be reasonable (to minimize dredging, minimize the amount of rip rap needed, and minimize property impacts). This resulted in a distance between the new ITT and the existing tunnel of 42 m.

The ITT crossing design consists of three separate types of construction: an immersed tube tunnel (covering the width of the river and extending on land more than a hundred meters into Richmond and Deas Island), cut and cover tunnels at either end of the ITT and ramps with retaining walls leading into the cut-and-cover tunnels. By extending the immersed tube tunnel as far as possible on land, the need for de-watering of the excavations required for the cut-and-cover construction could be minimized. Extension of the ITT onto land was accomplished by excavating temporary trenches into the banks on either side of the river, each more than a hundred meters long, to allow the first and last segments of the ITT to be floated in at any tide level. CST extended the immersed tube technology on land on both sides until the top of the ITT was at an elevation of -1.0 m.

The MUPs within the ITT could be conveniently placed on each side of the new tunnel to allow them to be used for emergency egress in the event of a fire in the tunnel. The Fire Life Safety requirements could be satisfied by this configuration.

The portals of the new tunnel were raised to an elevation of +4.38 m to provide flood resiliency to the tunnel. This height allows for 1 m of future sea level rise due to climate change, and results in the roadway being approximately 2 m higher than the current entrance/exit of the tunnel. It is possible that the Provincial Dike Authority may require additional height for this flood protection, but this could be accommodated readily if required.

In addition to the new ITT, the Deas Slough bridge would be replaced with a new bridge. The slough was filled in for the original construction, so the existing bridge is relatively short. CST has assumed that the slough would not be filled in for the new


crossing, and this resulted in a bridge that would be approximately 310 m long. CST has assumed that the vertical clearance under the new Deas Slough bridge would be the same as the clearance under the existing bridge.

The Ministry asked CST to investigate the possibility of connecting River Road across Highway 99 based on the understanding that the City of Delta may want to add the crossing in the future. CST confirmed that the geometrics would allow River Road to go over Highway 99. A possible overpass concept is shown in Appendix C. The cost of the River Road improvements is not included in CST's work as the River Road improvements are not part of the GMC project.

More detail of CST’s technical work for the ITT options is included in Appendix C.

3.2.5 Long Span Bridge For the long span bridge options, CST applied our past knowledge to develop the six-lane and eight-lane cross sections, and approach span lengths. Similar to the ITT options, an upstream alignment was selected for the bridge options. Initial designs included a clear-span main section across the Fraser River to avoid in-river impacts, and approach spans with piers on either side including across Deas Slough. A rendering of this option is shown in Figure 4.

Figure 4: Rendering of Eight-Lane Bridge Option 1 (see Appendix K for additional renderings)

A subsequent refinement was developed to also avoid piers in Deas Slough by adding a second cable-stayed span. A rendering of this option is shown in Figure 5.


Figure 5: Rendering of Eight-Lane Bridge Option 2 (see Appendix K for additional renderings)

The distance between the foundations of the new bridge and the existing tunnel would be approximately 10 m. This results in a distance between the edge of the bridge deck and the edge of the existing tunnel of approximately 25 m. Since the bridge foundations selected by CST are drilled shafts, there would be no concern about vibration induced damage or settlement of the existing tunnel as there would be no impact driving of piles. This separation was selected based on providing sufficient room for construction equipment.

The required shipping envelope was assumed to be the same as that required for the previous George Massey Tunnel Replacement project (see Navigation Clearance Envelope dimension in Section 3.2.1 above).

The Independent Technical Review (Westmar Advisors, December 2018) identified that cost savings could be achieved by shortening the cable-stayed bridge and placing the piers in the river. CST therefore performed a comparison of the bridge cost based on a "short" cable-stayed bridge versus a "long" cable-stayed bridge. For the short option, the main piers would be placed in the river, resulting in a main span of approximately 350 m. For the long option, the main piers would be placed on the shores of the river, resulting in a main span of approximately 650 m. However, because the river piers would need to resist significant ship impact loads (assumed to be from a 60,000 DWT vessel), CST's analysis determined that there would be little, or no cost savings associated with shortening the cable-stayed bridge.

The Ministry asked CST to investigate the possibility of connecting River Road across Highway 99 based on the understanding that the City of Delta may want to add the crossing in the future. The underside of the bridge deck is slightly less than 5 m above River Road. With some minor re-alignment of River Road, it could pass under the Highway 99 mainline and allow River Road to be connected east to west. The


cost of the River Road improvements is not included in CST's work as the River Road improvements are not part of the GMC project.

More detail of CST's technical work for the Bridge options is included in Appendix D.

3.2.6 Geotechnical The COWI-Stantec Team has extensive experience with the geotechnical conditions at the George Massey Crossing, and provided support to the Bored Tunnel, ITT, and Bridge Leads to support their work.

The soil conditions at the crossing are relatively uniform along the length of the project. The upper 30 m to 35 m of soils consist of loose sands that are assessed to be liquefiable during the three levels of the design earthquake (i.e.: 475, 975 and 2,475-year return period motions).

Compressible silts and clays interlayered with sands extend from approximate elevations of -30 m to -315 m. Very dense sand and very stiff to hard silt/clay, likely to be glacial till, is located approximately below elevation -315 m. Thickness of this till-like soil layer is estimated to be about 700 m.

The top liquefiable soil layer created significant challenges for the tunnel options (this dictated the depth of the deep bored tunnel) and resulted in the need for significant ground improvement for the tunnel options, bridge options, and the retrofit of the existing tunnel. Ground improvement using vibro-replacement stone column method was assessed to be the suitable option for the GMC project. Stone columns to 35 m depth is the maximum known attempted depth worldwide. Available borehole data in the river is limited to an elevation -40 m (Geodetic). There is an unknown risk that there could be liquefiable soils present at depths deeper than elevation -35 m, which could adversely affect the ITT particularly, however based on the available information, CST believes that this risk is low.

The underwater excavation needed for the ITT was checked for slope stability. It was determined that the underwater temporary cut slope would be stable at a slope of 2-to-1 (horizontal-to-vertical). To provide added safety, CST used a slope of 2.3-to-1 for the purpose of the conceptual design.

Given the extreme depth of the glacial till, bridge piers would be founded in the silt and clay. Based on the data from previous pile load tests, as well as the extensive bore holes in the project area, pile lengths between 70 m and 90 m are expected to be required.

More details of CSTs' geotechnical technical work are given in Appendix E.


3.2.7 Environmental The COWI-Stantec Team provided high-level environmental input to support the assessment of the short-listed options, including permitting and regulatory considerations that would affect timing for completion, and the expected environmental indicators for planning and risk assessment. These indicators included sensitive species and Species at Risk, air quality and emissions, contamination risk, regulatory complexity and uncertainty, marine traffic, visual aesthetics, land use (and ALR in particular), Indigenous interests and construction challenges. Potential environmental opportunities were also considered.

This high level input confirmed significant environmental risk associated with DBT technology and different but likely manageable impacts for ITT and bridge technologies. It is noted that the Ministry will conduct further environmental work as project planning continues.

More detail of CST's environmental work is included in Appendix F.

3.2.8 Hydrotechnical CST performed a preliminary hydrotechnical evaluation of the underwater excavation needed for the ITT.

Two options were investigated:

› an excavation for the new ITT using an underwater sheet pile retaining wall between the excavation and the existing tunnel; and

› a double sloped excavation for the new ITT.

The blunt face of the underwater sheet pile wall would cause local turbulence that is expected to make it difficult to work on the river above the excavation, but this option was found to be feasible.

The double slope excavation would result in the river slowing locally due to the added depth, which could result in local deposition of material into the excavation. Other than this, the excavation is not expected to be a concern to the hydraulics of the river between August and February (inclusive). If the excavation is left open during the freshet, there is a risk of the excavation moving upstream or downstream, and therefore care would need to be taken if the ITT sections are not installed, and the excavation is not backfilled before the freshet.

More detail of CST's hydrotechnical work for the ITT options is included in Appendix G.


3.2.9 Traffic and Highway Geometrics

Traffic

The COWI-Stantec Team performed macro Regional Traffic Modelling (RTM) to estimate the traffic volumes on the road network around and on the George Massey Crossing. The time horizons investigated were 2017 (the baseline date of the RTM model), 2035, and 2050. All scenarios included recent updates to regional demographic forecasts as well as planned transportation system expansions/improvements for the appropriate time frame.

Today, the George Massey Tunnel carries approximately 85,000 vehicles per day on average, approximately 10% of which are trucks. Additionally, transit represents approximately 1% of the vehicle trips, but carries approximately 10% of the people at the crossing. During the year, daily traffic can vary anywhere from 79,000 vehicles per day during the fall and winter periods to over 92,000 vehicles per day during the summer periods. During the morning and afternoon rush hour periods when the counter-flow lanes are in effect, the tunnel carries approximately 5,000 vehicles per hour in the peak direction and approximately 1,500 vehicles per hour in the off-peak direction. Current demands are between 4,800 and 5,400 vehicles per hour in the peak direction and between 2000 and 2500 vehicles per hour in the off-peak direction. Since the demands are at or above what the tunnel can process, weekday vehicle queues and corresponding delays for cars and commercial vehicles can be significant in both directions during the morning and afternoon three-hour periods.

During weekday midday and evening periods, as well as on weekends, when the tunnel supports two travel lanes in each direction, traffic volumes are slightly below the capacity of the two-lane crossing contributing to some moderate delays, particularly when heavy commercial vehicles are most prominent.

Table 2 shows the forecast 2035 and 2050 demands (veh/hr) assuming an eight-lane crossing with three GP lanes and one dedicated bus lane in each direction, along with current estimated peak hour demand for reference. The forecast volumes are effectively the same for all three technologies (Deep Bored Tunnel, Immersed Tube Tunnel, and Bridge). As illustrated, traffic demand during rush hour is projected to increase over the next 30 years.

The directional capacity of the new GMC is estimated at approximately 5,400 veh/hr assuming a lane capacity of 1,800 veh/hr. This is a significant improvement over the capacity of the existing tunnel, which is between 1300 and 1600 veh/hr per lane. The increase in capacity comes from the elimination of the counterflow system, general roadway geometry improvements, and improvements to the merging and acceleration/deceleration lanes on the new facility.


As evident from Table 2 , the demands northbound in the AM peak period, and southbound in the PM peak period are close to, or exceed, the available capacity of GMC.

Table 2 – Current and expected peak hour demands (veh/hr)

Time Period Direction 2017 Current

Demand 2035 GMC 8

Lane Demand 2050 GMC 8 Lane Demand

AM Peak Hour NB 4880 5300 5570 SB 2010 3280 3460

PM Peak Hour NB 2470 3820 4050 SB 5410 5960 6300

The planned eight-lane George Massey Crossing including a dedicated bus-only lane in each direction would support improved mobility for sustainable modes, goods movement as well as vehicular travel through:

• Dedicated bus-only lanes, which would support the existing two minute services in peak directions with increasing service levels and capacity through the introduction of double-decker buses over the next few years. Dedicated lanes would connect with bus-on-shoulder facilities both north and south of the existing crossing and would ultimately support increased ridership to/from South of Fraser communities;

• Dedicated pedestrian and cycling facilities between Richmond and Delta connecting into TransLink's Major Bike Network that serves urban centres across Metro Vancouver;

• Additional capacity serving off-peak directional travel as well as midday and weekend traffic, including commercial vehicles supporting regional, provincial and national trade corridors. The additional capacity for off-peak periods would be particularly important for summer periods when daily traffic is highest; and,

• Improved safety and incident management with active lane-management and improved responses.

The combination of removing buses from general traffic lanes, increased transit service, and moderate improvements in general purpose capacity due to wider travel lanes and improved safety would help improve travel time speed and reliability and reduce congestion. Continued improvement in transit service levels between South of Fraser and Richmond / Bridgeport Station also would be needed to further reduce congestion during these times, as is the case in other parts of the region, to provide attractive alternatives, manage demands and support regional and provincial goals for sustainable modes and climate action.


Additionally, improved utilization for the bus-only lanes could be considered through alternative lane designations (HOV/transit, auxiliary lanes) to avoid or minimize peak period queues in future. In this regard, technical strategies could be considered at subsequent states of planning and design, to address some of the growth in vehicle queues while maintaining priorities for transit on the new crossing.

The traffic volumes forecasts developed by CST were based on preliminary laning design concepts available in August/September 2019. Since that time, minor ongoing modifications to the design in the vicinity of the adjacent interchanges were made in response to the forecast volumes, but these are not expected to change the modelling results significantly.

Highway Geometrics The COWI-Stantec Team developed plan and profile layouts for each of the six short-listed options based on the design criteria outlined in Section 3.2.1 above.

Several iterations were completed for each alignment option as the Bored Tunnel Lead, ITT Lead, and Bridge Lead developed their individual solutions. The alignments for each of the short-listed options are shown in the tables in Section 3.3 below.

More detail of CSTs' technical work for the traffic and highway geometrics is given in Appendix H.

3.2.10 Examples of MUPs in Existing Tunnels The COWI-Stantec Team performed a search for examples of bike lanes and pedestrian walkways in tunnels from around the world. Several examples were found of MUPs in tunnels, an example being the Amsterdam Central Station Tunnel as shown in Figure 6.


Figure 6: Example of an existing MUP in a tunnel

A memo showing additional MUPs in tunnels around the world is included in Appendix I.

3.2.11 Estimated Range of Total Project Cost for the Eight-Lane Options

CST developed estimated order of magnitude, total project costs for the eight-lane DBT, ITT, and Bridge options once the concept design for each option had progressed sufficiently. These costs were given in terms of ranges and allowed for relative comparisons between the various options as the project progressed but are not considered suitable for budgeting purposes.

The estimates included construction cost, design cost, owner costs, property acquisition costs, environmental offsetting costs, escalation, interest during construction, and an allowance for risk and contingencies.

CST's estimated total project cost for each eight-lane option was as follows:

› Deep Bored Tunnel: between $12 and $17 billion.

› Immersed Tube Tunnel: between $4 and $5 billion.

› Bridge: between $3.5 and $4.5 billion.

Additional detail on the estimated cost ranges carried out by CST is presented in Appendix J.


Following the meeting the Ministry had with the Task Force on October 2, 2019, the Ministry requested that CST develop detailed project cost estimates for the eight-lane ITT option and the eight-lane Bridge option (for the purpose of the Bridge option, the Ministry requested that Option 2 be evaluated). These detailed cost estimates were not complete at the time of writing this report.

3.2.12 Estimated Design and Construction Schedule CST estimated the design and construction schedules for the six short-listed options.

Estimated Design Schedule

The design schedule for all six short-listed options is expected to be similar – all taking between one and two years. Depending on the procurement strategy, there is a possibility of overlapping the design schedule with the construction schedule (e.g. design-build or forms of early contractor involvement procurement methods).

Estimated Construction Schedule

The construction schedule for the options is expected to be as follows:

› Deep Bored Tunnel: approximately seven years (plus an extra year to seismically upgrade the existing tunnel after traffic is transferred to the new facility);

› Immersed Tube Tunnel: approximately five years (plus an extra year to close the portals of the existing tunnel and recommission it for utility only use); and,

› Bridge: approximately five years (plus an extra year to close the portals of the existing tunnel and recommission it for utility only use).

The construction schedule for the ITT is driven by the "fish windows" in the Fraser River, and also by the flow levels of the river. At the Massey Crossing, construction is permitted in the river between mid-June and the end of February. However, due to the flows of the freshet, the flow of the river is still significant in June and July, making it difficult to work on the river in these months. As such, for the ITT options, work in the river is likely limited to a 6-month or 7-month work window each year. This imposes a schedule risk that would need to be considered since if the construction falls behind, critical path items could be delayed by 6 months, or even potentially a year.

For the six-lane options and the eight-lane DBT option, seismic upgrading of the existing tunnel is expected to be completed after traffic is moved to the new facility, and this is expected to take an additional year.

Similarly, recommissioning of the existing tunnel for the eight-lane ITT and Bridge options (closing the portals, securing the tunnel for utilities, etc.) is expected to be


completed after traffic is moved to the new facility, and this is also expected to take an additional year.

3.3 Summary of CST's Technical Findings for the Short-List Options

The following provides a technical summary for the six short-listed options. The information in these summary pages is based on the findings of the technical memos provided in the appendices of this report.


OPTION A) – EIGHT-LANE DEEP BORED TUNNEL OPTION

› Two dedicated bus lanes - In new twin bored tunnels

› Six general purpose lanes - In new twin bored tunnels

› One bi-directional multi-use path - In the existing tunnel

DESCRIPTION NEW STRUCTURE › General Purpose Lane Width: 3.7 m

› Dedicated Bus Shoulder Lane Width: 3.7 m

› Multi-Use Path: Bi-directional in existing tunnel

› Shoulder widths: 1.0 m median shoulder, 2.5 m outside shoulder

› Tubes assumed 28 m apart (~1.5D) to allow for cross passages if needed

› Tubes are assumed to have 46 m (2.5D) of soil on top of the tubes under the Fraser River and Deas Slough to provide a reasonable factor of safety against floatation in earthquake

TYPICAL CROSS-SECTIONS

Typical New Bored Tunnels

Typical Existing Tunnel

PROJECT OVERVIEW › Approx. high-level project costs: Order of magnitude project cost – $12 to

$17B including construction, design, owner costs, property, environmental offsetting, escalation, interest during construction, risk and contingencies.

› Approx. project durations (some can overlap, so do not sum to get project schedule):

1-2 years for design, 7 years for construction, 1 year for retrofit old tunnel. Note, assumes 2 tunnel boring machines

KEY CONSIDERATIONS › Traffic Operations: General traffic queues on the Highway 99 mainline expected to be

similar to other options, however the stacked configurations of the traffic, plus the length of the bored tunnel creates an operational issue at Steveston Highway and Highway 17A since the traffic can not get into the correct lane unless the entrance/exit points are far enough from the tunnel entrance to allow the necessary weaving to occur. Significant queues expected on the single lanes through the tunnel that serve the Steveston Highway and Highway 17A interchanges.

› Ground improvement: Ground improvement expected to be required for approximately 600 m each end of the tunnel, under and around the portals, and for retrofit of existing tunnel.

› Environmental consideration: Risk of sink hole in river would have a significant environmental impact; ground improvements would be needed across the river for existing tunnel; disposal of excavated material. Expected to require a new EA.


OPTION A) – EIGHT-LANE DEEP BORED TUNNEL OPTION (CONTINUED)

› The diameter of the bore would be larger than “Bertha” that was used for SR99 in Seattle and would be a world record size of boring machine (18.5 m outside diameter, 17 m inside diameter).

› Assumed cross passages would not be required between the bores.

› Portals would need to be raised to 4.38 m Geodetic elevation for flood resiliency purposes (max flood height including sea level rise).

› Very significant launch pits for the boring machine would be required. Deep construction of these would be challenging given the weak soils and are considered to be a significant risk for the project.

› Maintaining traffic on Highway 99, Steveston Highway, and Highway 17A during construction of the portals would be challenging and would require extensive temporary works.

› Significant impact to lands in the Agricultural Land Reserve.

› Connections between Highway 99 and the interchanges at Steveston Highway and Highway 17A would be complex and would add travel time for all users.

› The new portals are expected to be located upstream of the existing one on the North side (Richmond) and downstream of the existing one on the South side (Ladner).

› The Steveston Highway interchange and the Highway 17A interchange are expected to have to be completely replaced.

› The MUPs are expected to be in the existing tunnel given the depth and length of a DBT crossing. Lighting and ventilation improvements would likely be needed.

› Seismic upgrades to the existing tunnel would need to be designed and constructed.



PLAN

POSSIBLE INTERCHANGE CONFIGURATION AT ENDS OF TUNNEL TO ACCOMMODATE WEAVING NEEDED FOR STACKING AND UNSTACKING



PROFILE


OPTION B) – SIX-LANE DEEP BORED TUNNEL OPTION

› Two dedicated bus lanes - In the existing tunnel

› Six general purpose lanes - In new twin bored tunnels

› One bi-directional multi-use path - In the existing tunnel

DESCRIPTION NEW STRUCTURE › General Purpose Lane Width: 3.7 m

› Dedicated Bus Lanes: Opposing in the existing tunnel

› Multi-Use Path: Bi-directional in existing tunnel

› Shoulders width: 1.0 m median shoulder, 2.5 m outside shoulder

› Tubes assumed 25 m apart (~1.5D) to allow for cross passages if needed

› Tubes are assumed to have 44 m (2.5D) of soil on top of the tubes under the Fraser River and Deas Slough to provide a reasonable factor of safety against floatation in earthquake

TYPICAL CROSS-SECTIONS 2 x 17.5 m bores (16 m inside diameter)

Typical New Bored Tunnel

Typical Existing Tunnel

PROJECT OVERVIEW › Approx. high-level project costs: Not calculated but expected to be slightly

less than the eight-lane Deep Bored Tunnel option (due to the smaller diameter bore required).

› Approx. project durations (some can overlap, so do not sum to get project schedule):

1-2 years for design, 7 years for construction, 1 year for retrofit old tunnel. Note, assumes 2 tunnel boring machines

KEY CONSIDERATIONS › Traffic consideration: General traffic queues on the Highway 99 mainline expected to be

similar to other options, however the stacked configurations of the traffic, plus the length of the bored tunnel would create an operational issue at Steveston Highway and Highway 17A since the traffic can not get into the correct lane unless the entrance/exit points are far enough from the tunnel entrance to allow the necessary weaving to occur. Significant queues expected on the single lanes through the tunnel that serve the Steveston Highway and Highway 17A interchanges.

› Transit consideration: Directing transit to use the existing tunnel would add approximately 2-3 minutes in the northbound direction and 4-5 minutes in the southbound direction relative to eight-lane option. Traversing local networks such as River Road would increase transit travel times and reduce reliability further.

› Ground improvement: Ground improvement expected to be required for approximately 600 m each end of the tunnel, under and around the portals, and for retrofit of existing tunnel.

Ministry of Transportation and Infrastructure MEMORANDUM · December 2018, the Minister of...

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