Alto Tunnel Investigation & Cost Estimate Update

Size: px

Start display at page:

Download "Alto Tunnel Investigation & Cost Estimate Update"

Colin Dorsey
6 years ago
Views:

Alto Tunnel Investigation & Cost Estimate Update WEDNESDAY, SEPTEMBER 27, 2017 6:30pm Corte Madera Community Center Community Center

1 Alto Tunnel Investigation & Cost Estimate Update WEDNESDAY, SEPTEMBER 27, :30pm Corte Madera Community Center Community Center Department of Public Works 3501 Civic Center Drive, Suite 304 San Rafael, CA T / F marincounty.org/pw

2 Tonight s Agenda Meeting Purpose (6:30-6:45 p.m.) Presentation (6:45 7:30 p.m.) o Background o Drilling & Scanning Process o Results of Investigation o Cost Estimate Update o Next Steps Questions and Comments (7:30-8:30 p.m.) Department of Public Works Alto Tunnel Study September 27, Slide 2

3 Meeting Purpose Previous direction: o Evaluate property and right-of-way issues. o Collect additional information on the tunnel interior structure. o Revise & update cost estimates based upon the above. Purpose of tonight s meeting: o o o o Recap Alto Tunnel background. Learn how the investigation was conducted. Learn about the updated cost estimates for optional tunnel reconstruction and closure. Provide comments, input & questions on the updated cost estimates. Photo Credit: County of Marin Department of Public Works Alto Tunnel Study September 27, Slide 3

4 Tonight s Meeting The Alto Tunnel Study Is an investigation inside the tunnel to determine its physical condition. Is NOT a pathway feasibility study. Therefore, at this meeting We WILL report on what we saw inside the tunnel and the cost estimate updates. We will NOT discuss pros/cons of a pathway through the tunnel. Ground rules: Please do not interrupt presentation or responses to questions. Please write down all questions on comment slips, one question per slip. This will allow us to answer all questions and give us a record for website Q/A. Department of Public Works Alto Tunnel Study September 27, Slide 4

5 Alto Tunnel Study - Background HOW DID WE GET HERE? Photo Credit: Jeff Wong

6 Alto Tunnel - Background 1880s-1970s: operated as a railroad 1975: concrete plug and other modifications in north portal area 1981: Southern portal backfilled 1983: County received portions of RR right of way; tunnel ends retained by NWPRR 2001: Alto Tunnel Scoping Study (Volume I, Volume II) : Mill Valley to Corte Madera Bicycle & Pedestrian Corridor Study : Right-of-Way Research & Land Surveying : Current study of tunnel interior condition Department of Public Works Alto Tunnel Study September 27, Slide 6

Alto Tunnel - Background MV-CM CORRIDOR STUDY 2008-10 Study of 3 corridors between MV & CM o Increase

information, not select a preferred route or course of action Funded 100% by NTPP federal grant

7 Alto Tunnel - Background MV-CM CORRIDOR STUDY Study of 3 corridors between MV & CM o Increase access & improve safety Route A Horse Hill Route B Alto Tunnel Route C Camino Alto Purpose: Give information, not select a preferred route or course of action Funded 100% by NTPP federal grant Department of Public Works Alto Tunnel Study September 27, Slide 7

in 2010 $s) Tunnel segment only; no approaches o $48M-$60M along whole route CalPark Tunnel: 1,100 lineal feet, 31 wide

8 Alto Tunnel - Background MV-CM CORRIDOR STUDY-ALTO TUNNEL ROUTE Wornum in CM to MV-Sausalito pathway crossing of E. Blithedale in MV Alto Tunnel: 2,173 lineal feet, 16 wide o $40M-$50M cost (62% cont. in 2010 $s) Tunnel segment only; no approaches o $48M-$60M along whole route CalPark Tunnel: 1,100 lineal feet, 31 wide o $28M construction cost; approaches included Department of Public Works Alto Tunnel Study September 27, Slide 8

9 Alto Tunnel Background RIGHT-OF-WAY RESEARCH: Q1: Are there public rights to establish a pathway? We found: County holds the center portion of the Alto Tunnel Union Pacific RR holds the outer ends of the Alto Tunnel One private owner holds the southern most end of the Alto Tunnel Department of Public Works Alto Tunnel Study September 27, Slide 9

10 Photo Credit: Jeff Wong Alto Tunnel Study Geotechnical and Structural Investigation

11 Alto Tunnel Background Q2: What s the structural integrity of the tunnel interior? o Will it affect the 2010 cost estimates? Investigate the areas of the tunnel we knew little about: Center between concrete plug on north end and the pea-gravel filled area on the south end Update cost estimates for: Reconstruction as a multi-use pathway Stabilizing the tunnel via fill & permanent closure Department of Public Works Alto Tunnel Study September 27, Slide 11

Geotechnical & Structural Investigation Team McMillen Jacobs Associates (team lead & engineers) o Drill Tech (borehole drilling) o Area West Environmental (environmental analysis) o RSE

12 Geotechnical & Structural Investigation Team McMillen Jacobs Associates (team lead & engineers) o Drill Tech (borehole drilling) o Area West Environmental (environmental analysis) o RSE (surveying) o Renishaw (scanning) o Eisen Letunic (outreach & communications) Department of Public Works Alto Tunnel Study September 27, Slide 12

13 Site Plan with Borehole Locations 13

14 Scanning Profile with Borehole Locations Legend - UPRR Holdings

15 Underhill Site 15

16 Underhill Site Borehole Drilling 16

17 Underhill Site After Drilling B-1 B-2 Approximate Alto Tunnel Center Line 17

18 Chapman Site 18

19 Chapman Site Borehole Drilling 19

20 Chapman Site After Drilling B-5 B-4 B-3 20

21 Flush Mounted Borehole Covers Probe Hole Casing Heavy Duty Enclosure & Bolt Down Lid Probe Hole Plug 21

22 22 Results of Investigation

23 View from Borehole B-1 5 Collapsed rock, so no scanning possible 23

24 View from Borehole B-2 Borehole Casing 24 Collapsed rock so no scanning possible

25 View from Borehole B-3 Borehole Casing 25 Collapsed rock so no scanning possible

26 View from Borehole B-4 26 Water droplets visible hitting bottom of tunnel; scanning possible

27 View from Borehole B-5 27 Void in tunnel; scanning possible

28 Findings of Scanning-Borehole B-4 Findings of Scanning Borehole B-4 Inside Tunnel, Looking East Typical Timber Set Support Section 28

29 Findings of Scanning-Borehole B-4 Vertical Timber Set Typical Timber Support Section 29

30 Findings of Scanning-Borehole B-5 Location of borehole did not allow for compete scan Obtained two 2-D line scans: perpendicular and parallel to borehole orientation Line scans reveal that tunnel is intact at this location 30

31 31 Cost Estimating Process: Interpreted Tunnel Conditions

32 Cost Estimating Process: Examples of Multi-Use Pathway 32 Cal Park Tunnel

33 Basis of Design: Tunnel Reconstruction Cost Estimate Entire tunnel would be lined with steel sets and smooth shotcrete lining. Different support and excavation methods for different sections. This estimate is inside tunnel work only. Improvements outside the tunnel are not included; pathway improvement costs outside the tunnel are identified in 2010 Mill Valley/Corte Madera Corridor Study. 33

34 Tunnel Multi-Use Pathway Amenities Low Energy Lighting Radio Communication (leaky feeder) Emergency Call Stations at portals and 200-ft intervals Security cameras at 300-ft intervals Ventilation fans at 200-ft intervals Fire alarm and pull stations Sprinkler system in tunnel Fire hydrants at portals and wetstandpipes at 200-intervals Lockable gates at portals 34

35 Examples of Reconstruction: Intact Timber Set Sections 35

36 Example of Tunnel Reconstruction & Pathway: Intact Timber Set Sections 36

37 Examples of Reconstruction: Collapsed Sections 37

38 Example of Tunnel Reconstruction & Pathway: Collapsed Section 38

39 Cost Estimating Process: Fill and Permanent Closure Primary Holes Primary Holes: Fill tunnel with grout through the existing boreholes and North Portal 39

40 Cost Estimating Process: Fill and Permanent Closure Primary Holes Secondary Holes Primary Holes: Fill tunnel with grout through the 40 existing boreholes and North Portal Secondary Holes: Tertiary Holes, as needed Drill additional holes Inspect for significant voids Fill voids with grout

41 41 Cost Estimating Process: Interpreted Tunnel Conditions

42 2017 Cost Estimate Update Ranges: Tunnel Only Reconstruction & Pathway PROJECT CONSTRUCTION COSTS (Millions) 2017 (Millions) Subtotal Construction Cost $ $25.0 $ $26.6 Escalation 1 $0.4 - $0.6 Contingency $ $15.5 (62%) $4.4 $5.4 (20%) Total Construction Cost with Contingency $ $40.5 $ $32.6 PROJECT DEVELOPMENT COSTS Survey, Technical Studies, and Engineering Design (15%) $4.2 - $5.1 $4.0 - $4.9 Environmental Analysis, Documentation, and Permits (10%) $2.8 - $3.4 $2.7 - $3.3 Project Administration (10%) $2.8 - $3.4 $2.7 - $3.3 Construction Management (10%) $2.8 - $3.4 $2.7 - $3.3 Design Services During Construction 2 $1.3 Allowance to Address Right of Way Issues $0.5 - $1.5 $1.5 Total Project Development Costs $13.1- $17.1 $ $17.4 TOTAL ESTIMATED PROJECT COST costs escalated to 2017 values at 2% per year 2 Design Services during construction not included in 2010 cost estimate $ $57.6 ($40.6-$50.6 in 2010 $s) $ $50.0

2017 Cost Estimate Update: Tunnel Only Reconstruction & Pathway Subtotal Construction Cost $25.0 Escalation 1 $0.4 2017 (Millions) Contingency $5.0 (20%) Total Construction Cost with Contingency $30.

43 2017 Cost Estimate Update: Tunnel Only Reconstruction & Pathway Subtotal Construction Cost $25.0 Escalation 1 $ (Millions) Contingency $5.0 (20%) Total Construction Cost with Contingency $30.4 PROJECT DEVELOPMENT COSTS Survey, Technical Studies, and Engineering Design (15%) $4.6 Environmental Analysis, Documentation, and Permits (10%) $3.0 Project Administration (10%) $3.0 Construction Management (10%) $3.0 Design Services During Construction Allowance to Address Right of Way Issues $1.5 Total Project Development Costs $16.4 TOTAL ESTIMATED PROJECT COST $ costs escalated to 2017 values at 2% per year 43 2 Design Services during construction not included in 2010 cost estimate.

44 2017 Cost Estimate Update: Fill and Permanent Closure PROJECT CONSTRUCTION COSTS , (Millions) 2017(Millions) Subtotal Construction Cost $5.5 $4.5 Escalation 1 $0.02 Contingency $3.6 (65%) $0.9 (20%) Total Construction Cost with Contingency $9.0 $5.4 PROJECT DEVELOPMENT COSTS Survey, Technical Studies, and Engineering Design (15%) $1.4 $0.8 Environmental Analysis, Documentation, and Permits (10%) $0.9 $0.5 Project Administration (10%) $0.9 $0.5 Construction Management (10%) $0.9 $0.5 Design Services During Construction 2 $0.4 Allowance to Address Right of Way Issues 2 $0.3 Total Project Development Costs $4.1 $3.1 TOTAL ESTIMATED PROJECT COST cost escalated 44 to 2017 values at 2% per year $13.2 ($11.5 in 2010 $s) $8.5

45 Alto Tunnel Study Next Steps NEXT STEPS & OTHER WAYS TO PARTICIPATE Photo Credit: Jeff Wong

46 Next Steps Public Comments and Questions Tonight-comment cards Via or postal mail through October 11, 2017 Compiled and posted to the website Finalize the Alto Tunnel Investigation & Cost Estimate Update: October/November 2017 Department of Public Works Alto Tunnel Study September 27, Slide 46

47 After this effort is finished, what s next? Neighbors, community leaders, policy makers have community conversations about options CM, MV, or County policy makers could make a decision to: o Initiate the Alto Tunnel Project by a local jurisdiction Mill Valley, Corte Madera, County, other? (Work with UPRR) o Fill and permanently close/stabilize the tunnel (Work with UPRR) o Do no further work o Further implement other alternatives from 2010 MV-CM Corridor Study: Horse Hill, Camino Alto o Or decide to do something else Department of Public Works Alto Tunnel Study September 27, Slide 47

48 Contact & Information Coordinator Stay Informed and Participate Sign up for updates via & check Alto Tunnel Study webpage walkbikemarin.org/projects_alto.php Carey Lando, Senior Project Planner Marin County Department of Public Works 3501 Civic Center Dr., Room 304 San Rafael, CA Phone: (415) Department of Public Works Alto Tunnel Study September 27, Slide 48

Drive, Suite 304 San Rafael, CA 94903 415 473 6528 T / 415 473

49 Thank You ALTO TUNNEL INVESTIGATION & COST ESTIMATE UPDATE September 27, 2017 Department of Public Works 3501 Civic Center Drive, Suite 304 San Rafael, CA T / F marincounty.org/pw Questions & Comments Photo Credit: Jeff Wong

Alto Tunnel Study. Weekly Progress Report February 10, 2017

Alto Tunnel Study. Weekly Progress Report February 10, 2017 Alto Tunnel Study Weekly Progress Report February 10, 2017 Report 1/Rev. No. 1 February 13, 2017 Table of Contents 1.0 Project Activities... 2 1.1 Underhill Site Drilling Progress... 3 1.2 Underhill Site