September 19, 2017
The MDC’s South Hartford
Conveyance and Storage
TunnelPresentation to CONN-OSHA Roundtable
Andrew Perham,
CHMM - MDC
Brian J. McCarthy, PE,
CCM, PMP
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
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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
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About the MDC
� Metropolitan District Commission
� Non-profit municipal corporation providing water and sewer
services to the greater Hartford area
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� 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
Background – The Clean Water Project
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� 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)
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
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Regulator
River
Interceptor
Wastewater Combined Sewer Pipe
Interceptor Sewer to Treatment Plant
Sanitary Wastewater
RoadwayCatch Basin
Regulator
River
Wastewater/Stormwater Combined Sewer Pipe
Interceptor Sewer to Treatment Plant
Sanitary Wastewater
Stormwater Runoff
Interceptor
Sanitary Sewer Overflows
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Storage Tunnels – Common Approach to
Combined Sewer Overflow (CSO) Management
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� 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)
Public
Project Team
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Program
Manager
Design
Engineer
Construction
Manager
DEEP Towns
Utilities USACE
Other Projects
Tunnel Alignment – Connect the dots
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Final Alignment
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� 4 miles long, 18 ft ID, 6 intermediate drop shafts
� 7,300 feet of consolidation conduits
� Deep circular shaft pump station
Tunnel Route Flyover
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Hard Rock Tunnel Boring Machine (TBM)
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Building the Tunnel
Drilling the rock
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Building the tunnel lining
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Drop Shaft Schematic
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Hydraulic Drop Shafts in Operation
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Final Site Plan and Landscaping
Air
Treatment
Drop Shaft
Gate
Chamber
Driveway
Decorative
Fence
Property Line-
Back of Sidewalk
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Air Treatment System
Activated
Carbon
Ventilation
Fan
Geotechnical Investigation
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Geologic Profile
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Geotechnical Investigation
Support Design of
� Tunnel
� Adits
� Shafts
� Conduits
� Pump Station
By Investigating
� Rock and soil physical properties
� Geologic structure
� Faults
� Water
� Environmental
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Phased Investigation
� 2009 Preliminary Design
� 2012 – Basis of Design / Alignment
� 2013-2015 – Final Design
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
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Critical Areas of Inquiry
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� Faults
� Water
Risk Management
� Structured Risk Management Process Started Early
� Planning
� Identification
� Analysis
� Mitigation & Response
� Monitoring & Control
� Risk Workshops
� Risk Register
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Qualitative Risk Analysis – Likelihood and
Impact
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Example Register
Advancing Professional Construction and Program Management
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
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Contract Packaging
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Contract Packaging
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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
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Outreach and Communication
� Council briefings
� NRZ meetings
� Mailings / Flyers
� Business groups
� TBM Naming Contest
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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
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Tunnel Contract Procurement
� Advertised October 2015
� Bid February 2016
� 4 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, 2016
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Launch Shaft Site
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Launch
Shaft
Pump Station
Shaft
Drop Shaft Site
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Shaft Drilling Rig
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Advancing the shaft
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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
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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
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Access / Egress
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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
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Communications
� Every shift starts with a “take
5”
� Natural voice insufficient –
mine phone
� Job Hazard Analyses
� Signage
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Blasting
� Specialty subcontractor
� Coordinated with fire
departments
� No explosives stored on site
� Shafts, starter tunnel well
into next year
� Adit tunnels after TBM
mining
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Fall Protection
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OSHA Standard for Underground Construction
29 CFR 1926.800
� Training
� Access Control
� Ventilation
� Air Monitoring
� Illumination
� Fire Prevention & Control
� Drilling & Blasting
� Cranes & Hoists
� Emergency Procedures, Rescue Teams
� Recordkeeping
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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
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Schedule
• Sept/Oct 2015 – Construction Begins
• Spring 2018 – Tunnel boring begins
• Summer / Fall 2019 – Tunnel drive completed
• 2023 – Construction complete/facility in operation
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Questions?