Pushing the Envelope For 100 Years

Transcription

1 Pushing the Envelope For 100 Years Tunneling under the Chesapeake Bay The Parallel Thimble Shoal Highway Tunnel Presented by: Kevin Abt, PE Chesepeake Bay Bridge and Tunnel District Mike Kling, PE, PTOE Mott MacDonald, LLC 2018 Virginia Concrete Conference March 2, 2018

2 Parallel Thimble Shoal Tunnel Project Overview Project Constraints Existing Conditions Alignment & Profile Subsurface Conditions Tunnel Spaceproofing Concrete Elements Durability Requirements Tunnel Approach Structures Tunnel Segments Tunnel Ballast / Road Slab Highway Trestles and Fishing Pier Roadway Pavement & Other Incidental 2

3 Chesapeake Bay Bridge Tunnel Original and Parallel Construction In 1956, the CBBT Commission was enabled to build the fixed crossing. Original Construction; September 1960 to April 1964; Parallel Crossing Construction July 1995 to July cost - $200M; 1999 cost $187M; 2018 cost - > $750M World s longest bridge-tunnel complex at 17.6 miles long shore to shore Includes 12 miles of trestle, two one mile long tunnels, two bridges, 2 miles of causeway, 4 artificial islands and 5.5 miles of roadway

4 Parallel Construction Phase II Parallel Thimble Shoal Tunnel Tunnel Length: 5,738 feet ;Internal Diameter: 39 feet Configuration: Bored Tunnel two lanes and dedicated egress corridor Construction Start: August 2017; Completion September 2022 Design-Builder: Chesapeake Tunnel JV Curved Alignment From Existing Portal Islands Roadway Trestle Replacement Improved Traffic Operation Tunnel Service Buildings Fishing Pier Reconstruction New Tunnel Systems Safety and Technology

5 Project Constraints Alignment & Profile Design Challenges Maintaining Existing Portal Island Footprint Minimizing Impacts to Existing ITT and Approaches Alignment Touchdown Points on Existing Trestles Future Channel Dredging Elevations Existing Trestle Span Configuration Utilize Exiting Pile Bents / Existing Pile Bent Capacity Maintenance / Emergency Median Crossover Island Spaceproofing TRESTLE ASB C2 SB Roadway PI #1 NB Roadway PI #2 C3 C4 TRESTLE BSB 5

6 Project Constraints Subsurface Conditions Supplemental Investigations EXISTING PEAT LAYER Phase/Stage Phase 1 - Land Location Portal Island No. 1 (South) Scope 14 Bore Holes Phase/Stage Phase 2 - Marine Location Water Scope 12 Bore Holes Phase/Stage Phase 1 - Land Location Portal Island No. 2 (North) Scope 11 Bore Holes 6

7 Project Constraints Tunnel Spaceproofing 7

8 Project Constraints Tunnel Approach Structure Spaceproofing Tunnel Ventilation Building Approach Structure Bored Tunnel Portal Point Pump Station 8

9 Design Elements Durability Requirements Technical Requirements Provide an expanded facility connecting Southbound Trestles ASB and BSB with a 100 year Service Life; Includes all NEW Concrete Structures Cover and Reinforcement Considerations Replacement Considerations Concrete Mix Content; Design Testing; Mix Approval Includes all NEW Mechanical and Electrical Equipment Maintenance and Replacement Considerations Includes all NEW Marine Works and Fill Berms 100 Year Storm + Hurricane Considerations 9

10 Design Elements Tunnel Approach Structures 10

11 Design Elements Tunnel Approach Structures 11

12 Design Elements Tunnel Approach Structures Jet Grout Plug Permanent Slurry Wall Existing Splash Wall Jet Grout Plug For TBM Breakout Proposed Approach Structure Design Challenges Minimize impact to existing Approach Structures and Portal Island Facilities Spaceproofing of tunnel systems and associated Ventilation Building Ground and hydrostatic loading Use of Permanent Slurry Walls Waterproofing permanent structure Temporary loading and geometry of tunnel boring machine Ventilation Building Loading 12

13 Design Elements Tunnel Approach Structures Slurry Walls 4 to 5 thick reinforced concrete slurry wall panels; depth 5,000 psi concrete with deformed black steel 5 of concrete cover required on bar for 100 Year Service Life 60 Slurry wall panels per island Base Slab 3 thick base slab; 5,000 psi concrete with deformed black steel 4 concrete cover on bar for 100 Year Service Life Special treatments for roadway appurtenances / incidentals 13

14 Design Elements Bored Tunnel TUNNEL SEGMENTS TUNNEL CONCRETE BALLAST 14

15 Design Elements Tunnel Segments Permanent Loads: Ground / hydrostatic loading Interior Loads Buoyancy forces Sunken ship Vessel collisions Temporary Loads Govern: Segment handling during casting storage and transportation Segment erection &TBM forces 15

16 Design Elements Tunnel Segments Precast Concrete Segmental Lining Steel fiber reinforced (SFRC) 5,000 psi concrete Trapezoidal - 9 segments and 1 key Grouted in-place following installation 16

17 Design Elements Tunnel Segments Unique Application of Precast SFRC In Segments Used in SFMTA Central Subway 20 Dia (Under Construction) Used in Ohio River Water Tunnel 29 Dia (Under Construction) First known larger diameter roadway tunnel use in US 17

18 Design Elements Tunnel Ballast / Road Slab Ballast: Roller Compacted Concrete at 4,000 psi Unreinforced 100 Year Service Life; Also required for buoyancy Road Slab: Plain Hydraulic Cement Concrete at 3,000 psi Reinforced with Stainless Steel bar 30 Year Service Life 18

19 Design Elements Highway Trestles / Fishing Pier Design Challenges Horizontal Alignment Shift / Reuse of Existing Pile Bents Existing Trestle Span Type Configuration and Continuity Maintaining Existing Low Chord Elevation / Bent Cap Reconstruction Existing Pile Bent Capacity/ No New Driven Open Water Cylinder Piles 19

20 Design Elements Highway Trestles / Fishing Pier 20

21 Design Elements Highway Trestles / Fishing Pier New Concrete Elements Prestressed PA Bulb-T s (Highway Trestles) AASHTO Type IV Prestressed Girders (Fishing Pier) Existing Trestle Span Type Configuration and Continuity Abutment and Bent Cap Reconstruction Prestressed Concrete Square Piles Cast In Place Approach Slabs 21

22 Design Elements Highway Trestles / Fishing Pier Highway Trestles Prestressed PA Bulb-T s Uncoated Tensioning Strands / Stainless Mild Steel Lightweight (120 pcf) concrete 10,000 psi strength, Class A5 Cast In Place Concrete Superstructure, Bent Caps and Approach Slabs 4,000 psi, Class A4 with Stainless Steel Bar Prestressed Square Piles 5,000 psi, Class A5 with Black Bar 22

23 Design Elements Highway Pavement & Other Incidental Highway Pavement Cast In Place Concrete Base Slab 4,000 psi Hydraulic Cement Concrete per VDOT Standards South Plaza Substation Cast In Place Concrete Retaining Walls and Equipment Slabs 5,000 psi Concrete Standard Black Bar at 3.5 minimum cover for durability Duct Bank Cast In Place Concrete Encasement 3,000 psi Hydraulic Cement Concrete per VDOT Standards 23

24 Parallel Thimble Shoal Tunnel Rendering 14/03/

25 You can reach me by phone, or through our website. We look forward to questions you may have. Name Mike Kling, PE, PTOE E Michael.kling@mottmac.com T W mottmac.com 25

26 Thank you Mott MacDonald Opening opportunities Sustainability Goes Underground

27 Chesapeake Bay Bridge Tunnel Parallel Construction Phase I The CBBT Commission was enabled by the General Assembly and Governor to build the Parallel Crossing in Construction Cost: $187 Million Parallel Bridges/Trestles Construction July 1995 July 1999 Funded by revenue bonds

28 Project Overview 28

29 Project Constraints Alignment & Profile 29

30 Chesapeake Bay Bridge Tunnel Parallel Thimble Shoal Tunnel Tunnel Length: 5,738 feet Internal Diameter: 39 feet Configuration: Bored Tunnel two lanes and dedicated egress corridor Construction Costs: $756 Million Construction Start: August 2017 Construction Completion: September 2022 Design-Builder: Chesapeake Tunnel JV

31 Project Constraints Alignment & Profile 31

32 Project Constraints Subsurface Conditions 32

33 Project Constraints Protection of Existing Structures Condition Survey and Assessment Assessment of Short and Long Term Settlement/Movements Instrumentation & Monitoring: Baseline Monitoring Construction Monitoring 33

34 Design Elements Portal Approach Structures Cantilever Strutted Section TBM Launch Pit TBM Breakout Plug Jet Grout Plug Slurry Wall Toe 34

35 Design Elements Bored Tunnel 35

36 Design Elements Tunnel Segments Temporary Loads govern: Segment handling during casting storage and transportation Segment erection &TBM forces Mott MacDonald Presentation title 36