The MDC s South Hartford Conveyance and Storage Tunnel

Transcription

1 The MDC s South Hartford Conveyance and Storage Tunnel Presentation to CONN-OSHA Roundtable Andrew Perham, CHMM - MDC Brian J. McCarthy, PE, CCM, PMP September 19, 2017

2 Safety Moment Storm Watch: Be Prepared Anticipate high winds when storing materials Stay away from booms, towers, fences and trees during thunder and lightning storms; seek shelter Is your site subject to flash floods or poor drainage? Be a weather watcher 2

3 Presentation Topics Background Project Team Tunnel Alignment Drop Shafts Geotechnical Investigation Risk Management Contract Packaging Right of Way Acquisition Permitting Public Communication Construction Procurement Progress to-date Safety 3

4 About the MDC Metropolitan District Commission Non-profit municipal corporation providing water and sewer services to the greater Hartford area Member Towns: Bloomfield, East Hartford, Hartford, Newington, Rocky Hill, West Hartford, Wethersfield, Windsor Serves a population of 440,000 1,300 miles of sewers; 105 MGD treatment capacity 1,600 miles water main; Average 40 MGD consumption 4

5 Background The Clean Water Project Consent Order and Consent Decree program to control Combined Sewer Overflows (CSO) and Sanitary Sewer Overflows (SSO) 1 billion gal / yr (about 50 events/yr) Expand HWPCF capacity to 200 MGD 670 acres of sewer separation Tunnel storage and conveyance Reduce stormwater inflow/ groundwater infiltration (I/I) 5

6 Combined Sewer Overflows Dry day No problems Household sewage only (toilet, shower) Wet day During rain events the combined sewer cannot convey all the flow & results in overflows (CSOs) into streams/rivers Regulator River Interceptor Regulator River Interceptor Sanitary Wastewater Wastewater Sanitary Wastewater Catch Basin Interceptor Sewer to Treatment Plant Wastewater/Stormwater Interceptor Sewer to Treatment Plant Roadway Combined Sewer Pipe Stormwater Runoff Combined Sewer Pipe 6

7 7 Sanitary Sewer Overflows

8 Storage Tunnels Common Approach to Combined Sewer Overflow (CSO) Management Providence is closest recent example, operational in 2008 Others include Chicago (1980 s) Milwaukee (1990 s) Boston (2000 s) Atlanta (2000 s) Portland (2000 s) Cleveland (2010 s) Indianapolis (2010 s) Washington (2010 s) 8

9 Project Team Public DEEP Towns Other Projects Program Manager Construction Manager Design Engineer Utilities USACE 9

10 10 Tunnel Alignment Connect the dots

11 Final Alignment 4 miles long, 18 ft ID, 6 intermediate drop shafts 7,300 feet of consolidation conduits Deep circular shaft pump station 11

12 12 Tunnel Route Flyover

13 Hard Rock Tunnel Boring Machine (TBM)

14 14 Building the Tunnel

15 15 Drilling the rock

16 16 Building the tunnel lining

17 Drop Shaft Schematic

18 18 Hydraulic Drop Shafts in Operation

19 Final Site Plan and Landscaping Property Line- Back of Sidewalk Gate Chamber Drop Shaft Decorative Fence Air Treatment Driveway 19

20 Air Treatment System Activated Carbon Ventilation Fan 20

21 21 Geotechnical Investigation

22 22 Geologic Profile

23 Geotechnical Investigation Support Design of Tunnel Adits Shafts Conduits Pump Station By Investigating Rock and soil physical properties Geologic structure Faults Water Environmental Phased Investigation 2009 Preliminary Design 2012 Basis of Design / Alignment Final Design 23

24 Investigation 67 Deep Borings in Tunnel Corridor 30 Shallow Borings - Shafts & PS Cone Penetrometer Tests Wells and Piezometers Packer Tests, Slug Tests Borehole geophysics Surface geophysics Soil & Rock Testing 24

25 Critical Areas of Inquiry Faults Water 25

26 Risk Management Structured Risk Management Process Started Early Planning Identification Analysis Mitigation & Response Monitoring & Control Risk Workshops Risk Register 26

27 Qualitative Risk Analysis Likelihood and Impact 27

28 Example Register Advancing Professional Construction and Program Management

29 Contract Packaging Project designed as an integrated system Contract packaging based on Technical specialization Geography / Geology Mitigating interface risks Availability of funding Five Contracts 1. Utility Relocation 2. Main Tunnel and Shafts 3. Pump Station 4. East Conduits 5. West Conduits 29

30 30 Contract Packaging

31 31 Contract Packaging

32 Rights of Way Property Launch Shaft / Pump Station Drop Shafts Retrieval Shaft Subterranean Easements No Surface rights Defines tunnel construction envelope Precedent with Park River Auxiliary Conduit 32

33 Outreach and Communication Council briefings NRZ meetings Mailings / Flyers Business groups TBM Naming Contest 33

34 Tunnel Contract Procurement Prequalification Process Evaluation Criteria Technical Capability & Experience Commercial Key Personnel Safety JV Role DEEP review and approval of RFQ & process 14 Submittals 6 qualified 2 JVs, 4 independent Other Contract Provisions Dispute Resolution Board Escrowed Bid Documents 34

35 Tunnel Contract Procurement Advertised October 2015 Bid February bids received all joint ventures Low Kenny / Obayashi - $279.4MM Others Salini - Impregilio / SA Healy Traylor / Kiewit Shea / Skanska Contract executed June 2016, NTP August 1,

36 Launch Shaft Site Pump Station Shaft Launch Shaft 36

37 37 Drop Shaft Site

38 38 Shaft Drilling Rig

39 39 Advancing the shaft

40 Safety MDC is a Proactive Owner Prequalification process Active oversight Near misses / lessons learned Drills Contractor SSO key person Hazards Normal construction housekeeping, slips, trips, falls, heavy equipment Air Quality (gassy/non-gassy) Hoisting, conveyors Electrical Blasting Dust Confined Space Public Safety / Traffic / Critical Facilities (flood control, etc) Geotechnical monitoring Security / Access / visitor & worker orientation 40

41 Housekeeping A clean job is a safe job. Lots of heavy equipment traffic Kenny/Obayashi spends a great deal of time & effort keeping an clean & organized site. Space is tight 41

42 42 Access / Egress

43 Working at the Shaft Hazards pinch points uneven and slippery walking and working surfaces poor air quality struck by hazards water loose rock overhead objects 43

44 Communications Every shift starts with a take 5 Natural voice insufficient mine phone Job Hazard Analyses Signage 44

45 Blasting Specialty subcontractor Coordinated with fire departments No explosives stored on site Shafts, starter tunnel well into next year Adit tunnels after TBM mining 45

46 46 Fall Protection

47 OSHA Standard for Underground Construction 29 CFR Training Access Control Ventilation Air Monitoring Illumination Fire Prevention & Control Drilling & Blasting Cranes & Hoists Emergency Procedures, Rescue Teams Recordkeeping 47

48 Progress to Date Launch shaft cleared soil removal New wetlands constructed New access road to dike and highway tunnel Launch shaft excavated to tunnel crown Pump station shaft excavated to top of rock Retrieval shaft secant pile installation underway Drop shaft overburden drilling completed, rock drilling underway TBM manufactured, arriving this month 48

49 Schedule Sept/Oct 2015 Construction Begins Spring 2018 Tunnel boring begins Summer / Fall 2019 Tunnel drive completed 2023 Construction complete/facility in operation 49

50 Questions?