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TMC Meeting - TPO Miami River Tunnel Feasibility Study

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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TMC Meeting - TPO Miami River Tunnel Feasibility Study

  1. 1. • 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 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. 2. Study participants TPO Consultant team Project advisory committee 2 TRANSPORTATION and PUBLIC WORKS
  3. 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. 4. Study area context 4 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  5. 5. Study area context 5 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  6. 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 6 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  7. 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) 7 Typical Tunnel Profile MIAMI RIVER TUNNEL FEASIBILITY STUDY
  8. 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. 9. Construction Methodologies MIAMI RIVER TUNNEL FEASIBILITY STUDY 9 Bored Tunnel Cofferdam Cut-and-Cover Mining Immersed Tube
  10. 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 10 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  11. 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 11 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. 12. Preliminary river crossing locations • 6 basic locations • Plus potential permutations 12 16 3 5 4 2
  13. 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. 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 14
  15. 15. Typical section – twin bores 15 ROW limits ROW limits
  16. 16. Alternative 3A 4-lane, stacked bored roadways, staggered portals 16
  17. 17. Alternative 3A – Plan (North End) 17
  18. 18. Alternative 3A – Plan (South End) 18
  19. 19. Alternative 3A - Profile Stacked bored roadways, staggered portals 19 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  20. 20. Conceptual Cost Additives • Preliminary studies (PD&E, geotechnical, cultural resources, ROW elements) • Final design and engineering • Construction oversight • Special contingencies 20 • 4% • 6% • 12% • 10-20% Cost Estimate Exclusions • Right-of-way costs • Mitigations costs • Noise and vibration monitoring • Extraordinary spoil costs
  21. 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. 21 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  22. 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. 22
  23. 23. Traffic Overview 23 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. 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 24 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  25. 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 25 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  26. 26. Next steps • Confirm final cost estimates • Finalize study documentation • Review in coordination with TPO • Submit deliverables 26 MIAMI RIVER TUNNEL FEASIBILITY STUDY
  27. 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

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