Miami River Tunnel Feasibility Study (GPC VI Work Order 6) presentation, by ATKINS and Caltran Engineering, at the TPO Transportation and Mobility Committee (TMC) meeting on May 31, 2017.

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1
Miami River Tunnel Feasibility Study
Miami-Dade TPO GPC VI – Work Order 6
M-D TPO Governing Board
Transportation and Mobility Committee
May 31, 2017 – 2 pm

2. Study participants
TPO
Consultant team
Project advisory committee
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TRANSPORTATION
and PUBLIC WORKS

3. Study purposes
• Identify and define tunnel improvement concepts
that are technically feasible and implementable
• Determine advantages and disadvantages
• Provide conceptual-level cost estimates
• Define implementation strategy and schedule
• Prepare visualizations of preferred concepts
MIAMI RIVER TUNNEL FEASIBILITY STUDY 3

4. Study area context
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

5. Study area context
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

6. Key Assumptions
• Connection between Biscayne Blvd. and Brickell Ave.
• Two two-lane roadways
• Consider portal traffic operations conditions
• Avoid any right-of-way encroachments
• Retain existing Brickell Bridge in operation
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

7. Technical considerations
• Roadway
o Number of lanes and cross-section
o Lighting
o Emergency access
• Alignment elements
o Horizontal (curvatures, design speed)
o Vertical (stopping sight distance, profile)
o River channel dredged depth
o Storm surge overtopping (profiling or gates)
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Typical Tunnel Profile
MIAMI RIVER TUNNEL FEASIBILITY STUDY

8. Design criteria
• Tunnel design speed (35 mph)
• Roadway horizontal and vertical
geometry
– Grades: 6-7% maximum
– Curvatures: per design speed
– Clearances
• Sight distance
• Roadway cross-section elements
(similar to PortMiami)
• Minimum cover between channel
bottom and tunnel
MIAMI RIVER TUNNEL FEASIBILITY STUDY 8
• River channel dimensions
– Up to 150 feet wide
– -15 feet mean low water with
overdredge to -17 feet
• Other factors specific to
tunnel construction
method

9. Construction Methodologies
MIAMI RIVER TUNNEL FEASIBILITY STUDY 9
Bored Tunnel
Cofferdam
Cut-and-Cover
Mining
Immersed
Tube

10. Construction methodologies
• Cofferdam and Cut-and-Cover
o Not practical due to marine traffic
o Issues with environmental impacts
• Immersed Tube
o Not practical due to small crossing length,
alignment curves
o Issues with environmental impacts
• Bored Tunnel
o Feasibility demonstrated by PortTunnel
• Mining
o Alternative method that can be considered
o May require grouting and/or freezing techniques
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

11. Tunnel alternatives
• Minimum depth tunnel
o Approximately 2,400 feet long end
to end
• Moderate depth tunnel
o Approximately 3,600 feet long end
to end
o Would allow existing Brickell Bridge
to remain
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Minimum depth
Moderate depth
Minimum depth profile: 2,400 ft. min.
Moderate depth profile: 3,600 ft. min.
Depth: -125 ft.
PortMiami Tunnel: -120 ft.
Depth: -75 ft.

12. Preliminary
river crossing
locations
• 6 basic locations
• Plus potential
permutations
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16 3
5
4
2

13. Preliminary alternatives and
observations
1. Brickell Ave. – Minimum depth
o Would require removal of existing bridge
2. Brickell Ave. – Moderate depth
3. Brickell Ave. to Biscayne Blvd.
4. Brickell Blvd. to Biscayne Blvd. at Flagler St.
5. Brickell Key Dr. to Biscayne Blvd.
o Insufficient width and length for south portal; other issues
6. Brickell Ave. west to Fort Dallas Park
o Required curvatures not workable
Study focus is on Option 3. 13

14. Alignment development approach
• Avoid right-of-way encroachments
• Preserve sufficient lateral space within street right-of-way for:
o Maintenance of traffic
o Property access
o Construction requirements
• 1st – find workable roadway geometry
• 2nd – assess portal area compatibility with street cross-section
and property access issues
• 3rd – determine general construction method(s) and feasibility
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15. Typical section – twin bores
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ROW limits ROW limits

16. Alternative 3A
4-lane, stacked bored roadways, staggered portals
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17. Alternative 3A – Plan (North End)
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18. Alternative 3A – Plan (South End)
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19. Alternative 3A - Profile
Stacked bored roadways, staggered portals
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

20. Conceptual Cost Additives
• Preliminary studies (PD&E,
geotechnical, cultural resources,
ROW elements)
• Final design and engineering
• Construction oversight
• Special contingencies
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• 4%
• 6%
• 12%
• 10-20%
Cost Estimate Exclusions
• Right-of-way costs
• Mitigations costs
• Noise and vibration monitoring
• Extraordinary spoil costs

21. Development Schedule
PHASE_____________________DURATION______
• PD&E Study/EIS 3 – 4 years
• Final Design 2 – 2-1/2 years
• ROW clearance 2 – 3 years
• Construction 4 – 5 years
• Identification of funding sources TBD
for construction and operations
PHASES CAN BE FAST-TRACKED TO REDUCE DURATION.
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

22. Study Findings
• 2040 traffic demand
warrants a 4-lane
tunnel
• Alternative 3A (4-lane)
best addresses study
objectives
• Base 2017 capital cost
near $900 million
• Total 2017 cost with
additives is $1.27 billion
based on capital cost
experience for
PortMiami tunnel
• Excludes right-of-way
and potential financing
costs.
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23. Traffic Overview
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50% of bridge traffic extends from Port Blvd. to SW 15th Road
Select Link Analysis for Existing Bridge
• 50% of existing bridge traffic
extends beyond tunnel portals
• At least 20% extends to I-395 and
Rickenbacker Causeway
• With Brickell bridge in place
• Tunnel daily traffic = 43,000
vehicles
• Model shows high tunnel
directionality and rebalancing
of other bridge volumes
• Demand warrants a 4-lane
tunnel
• Tolling could be tool to:
o Regulate tunnel use to ensure
proper traffic service
o Generate revenue
o Concept needs further study
2040 Traffic Demand

24. Alt. 3A – Refinements to be addressed
• Strategy for capital funding and ongoing operations costs
• Addressing ROW encroachments at Miami Circle and Biscayne Blvd.
at Miami River
• Coordination of north portals with Biscayne Blvd. planning projects
• Tunnel spoil disposal sites and access routing
• Remote staging sites for construction materials and employee parking
• Maintenance of traffic plans and detour strategy
• Construction staging and sequencing
• Community outreach strategy during construction
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

25. Funding and financing strategies
• Conventional delivery and financing
• P3 approach for delivery and/or finance of capital funding
and ongoing operations costs
• Special Assessment District
o As utilized for local share of Metromover capital cost
• Tolling
o Tunnel demand management
o Funding for operating costs
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

26. Next steps
• Confirm final cost estimates
• Finalize study documentation
• Review in coordination with TPO
• Submit deliverables
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MIAMI RIVER TUNNEL FEASIBILITY STUDY

27. • The six-column grid controls the structure and layout
of all the presentation’s information. A consistent
hanging line allows for a regular and stable point
from which to structure everything.
• PowerPoint guides have been set up within this
template based on this six-column grid, in order to
help you position your content. To turn the guides
on, go to the ‘View Tab’ and check the box labelled
‘Guides’.
Notes: The six-column grid
27
Miami River Tunnel Feasibility Study
Miami-Dade TPO GPC VI – Work Order 6
M-D TPO Governing Board
Transportation and Mobility Committee
May 31, 2017 – 2 pm