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?