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Tunnel Updates – October 2023

Three times per year, TBM: Tunnel Business Magazine recaps the status of major tunneling projects underway in the United States and Canada. Below is the Tunnel Update that appeared in the October 2023 issue of the print edition.

CALIFORNIA

Carson, Los Angeles and Rancho Palos Verdes

Joint Water Pollution Control Plant Effluent Outfall Tunnel
Dragados USA

The Los Angeles County Sanitation Districts (Sanitation Districts) are undertaking the Joint Water Pollution Control Plant Effluent Outfall Tunnel project, which will serve the sanitation needs of approximately 5 million people in 73 cities and unincorporated areas of Los Angeles County. The project is part of the Sanitation Districts’ Clearwater Program, which evaluates infrastructure and facilities needs through the year 2050 and makes recommendations on how to maintain a reliable and cost-effective wastewater management system. NTP was issued April 8, 2019, with 1,953 working days to complete the work and an estimated completion date of mid-2027. The bid price was $630.5 million.

As part of the implementation of the Clearwater Program, the Sanitation Districts is constructing a tunnel approximately 7 miles long and 21.5 ft in excavated diameter (18 ft in internal diameter) to convey disinfected, secondary-treated effluent from the Sanitation Districts’ Joint Water Pollution Control Plant (JWPCP) located in the City of Carson to an existing ocean discharge system at Royal Palms Beach in San Pedro in the City of Los Angeles. The tunnel will provide better seismic resiliency, provide additional capacity for population growth and storm events, and will provide redundancy for the two existing tunnels that were constructed in 1937 and 1958, which have not been inspected in nearly 60 years.

The tunnel begins at the JWPCP Shaft Site (entry shaft) and ends at Royal Palms Beach (exit shaft). The tunnel alignment varies in depth from approximately 50- to 450-ft below the ground surface. The entire tunnel alignment will be below the groundwater table with pressures ranging from 1 to 9 bar. As part of the scope, a 14-ft diameter cast-in-place concrete connection will be constructed to convey the treated effluent from an existing force main to the proposed JWPCP Shaft. Other notable project features include an approximately 60-ft diameter and 113-ft deep drop shaft, a junction structure and two valve structures at the JWPCP and a manifold structure at Royal Palms Beach.

Tunneling will go through two distinct ground conditions. The first half of the tunnel will be through soft ground with depths up to 110 ft. The second half of the tunnel will be through hard rock with depths up to 450 ft, where the tunnel will be subjected to intense ground squeezing conditions due to the overburden pressure.

The tunnel lining consists of bolted and gasketed precast concrete segments. Tunneling will go through splays of the Palos Verdes Fault Zone where 16-ft diameter steel liner will be used within the 18-ft diameter concrete segments to accommodate displacement from seismic events at two locations. When in operation, the tunnel will be under hydrostatic pressure. In the first half of the alignment, internal pressure will exceed the external pressure and post-tensioning of the concrete segmental liner will be necessary. To offset the “hoop stress” developed from internal pressure, a post-tensioning system consisting of internal steel tendons along the circumference of the concrete liner was specified. This post tensioning design is unique and has only been used a few times in the world, but never before in North America. In the second half of the alignment, the hard rock around the tunnel will offset the internal pressure, and post-tensioning will not be required.

Work at the JWPCP Shaft Site started in summer 2019. Construction of the access shaft slurry wall excavation support system was completed in December 2019. Excavation of the shaft in dry and wet conditions, which was followed by shaft tremie slab construction and dewatering, was completed August 2020. Open cut construction of the 14-ft diameter cast-in-place concrete Connection A from the proposed Junction Structure No. 1 to the JWPCP Shaft was substantially completed in October 2020. Jet grouting activities for the tail tunnel, starter tunnel, and three safe havens were completed in May 2021. Excavation of the starter and tail tunnels was completed in May 2021. The Contractor is using a Herrenknecht slurry TBM, which arrived onsite in late 2020. The TBM was named “Rachel” in honor of Rachel Carson, who authored the book Silent Spring that was credited with sparking the global environmental movement. Fabrication of test precast concrete segments at the Traylor Bros., Inc. Littlerock, California facility began in April 2021. Tunnel machine launch began in the Fall of 2021, with production mining beginning in early-2022. Tunnel mining is anticipated to be completed by early-2025. Multiple hyperbaric interventions for TBM cutterhead inspection and maintenance have been successfully completed to date. Three planned maintenance stops at Safe Havens 1, 2 and 3 were also completed. Approximately 17,500-feet or 48% of the tunnel lining has been installed to date.

Project Paries – Lead Design Consultant: Parsons; Tunnel Design Consultant: Delve Underground; Tunnel Consultant: Mott MacDonald/BabEng; Listed Major Subcontractors for Dragados – Excavation and Structures: W.A. Rasic Construction Company, Inc.; Jet Grouting and Support of Excavation: Malcolm Drilling Company, Inc.

Personnel: Los Angeles County Sanitation Districts – Construction Management Section: Matthew Palma, Section Head; Russell Vakharia, Resident Engineer/Construction Manager; Sewer Design Section: Anthony Howard, Section Head; Oscar Morales, Supervising Engineer; Yoonkee Min, Senior Engineer; Parsons – Danson Kelii, Project Manager; Delve Underground – John Stolz, Lead Tunnel Design Consultant; Mott MacDonald – Brendan Reilly, Lead Tunnel Consultant; Chris Peiler, Lead Tunnel Engineer; Dragados – Matt Kendall, Project Manager; John Truong, Deputy Project Manager; Nicholas Karlin, Project Engineer.

Groveland

Mountain Tunnel Improvements Project
Michels Tunneling

This $139 million project for the San Francisco Public Utilities Commission (SFPUC) is in the central Sierra Mountain Range near the town of Groveland in Tuolumne County. The existing tunnel begins at Early Intake Reservoir on the Tuolumne River and extends approximately 19 miles west to the Priest Reservoir, near the town of Groveland. NTP was issued Jan. 29, 2021, and the estimated date of completion is December 2026.

The scope of the work includes: existing tunnel interior repair and modification work within the 19 mile tunnel length which includes; concrete lining repairs, contact grouting, pressure grouting, approximately 5,000 lf of new concrete invert paving, demolition of existing bulkheads and installation of new bulkheads, bulkhead improvements and debris removal; construction of new tunnel improvements which includes a new Flow Control Facility (FCF) which is comprised of a 55-ft diameter, 150-ft deep new shaft, bypass tunnels and connections with the existing tunnel; the construction of new portal, 1,075 ft long adit, tie-in of the adit to the existing tunnel, construction of a new access shaft with a new connecting adit, new siphon extension of about 300 ft with an inclined shaft connecting to the existing tunnel and installation of approximately 1,500 ft of steel pipe lining. Other work within the project limits includes construction of permanent spoil fill sites, installation of a water filtration system during the tunnel shutdowns and water treatment plant for construction water discharge, road/slope stabilization for the adit access roads, various types of retaining walls, a micro pile supported concrete deck, environmental permit compliance and other site improvements and restoration.

The 150-ft deep and 55-ft internal diameter FCF shaft will be constructed primarily in a schist formation. The FCF bypass tunnels, which are horseshoe shape with varying dimensions, will also be constructed in schist. The 1,075-ft long horseshoe shape adit will be constructed in both diorite and schist. The 100-ft deep and 17-ft internal diameter access shaft and bypass tunnel siphon extensions will be constructed in diorite. It is expected that drill and blast will be the construction method for all underground construction.

The project is approximately 46% complete. Successful completion of Outage No. 2 which included completing the tie-in with the Mountain Tunnel for the New Priest Adit and the connection of the upstream/downstream bypass tunnels with the existing tunnel, installing all large diameter water piping within the FCF facility, constructing a new rock trap, and completing some of the tunnel lining repair within the Mountain Tunnel. Work continues in the Priest Adit to prepare for the upcoming final lining installation. Work is continuing in the FCF shaft with completion of the waterproofing membrane and on-going construction of the cast in place final lining. Work continues on the many tunnel access road improvements along the project corridor. In addition, the contractor has completed repairs of the storm damage sites within the corridor caused by the winter storms of 2022/2023.

The objectives of the Mountain Tunnel Improvements are to rehabilitate the tunnel and to make improvements to extend the useful life of this asset for the next 100 years. This project will require five winter season tunnel outages of 60 to 100-day durations each to complete the in-tunnel repairs and other work inside the tunnel and to construct the tie-in connections between the existing tunnel and the new improvements.

Lead Design Consultant is Delve, SFPUC Construction Management Bureau is the construction manager, construction management and construction inspection provided by AECOM; Major coordination with Hetch Hetchy Water and Power, Ted Allen; Major Michels subcontractors include Kroner Environmental, Schrader Mechanical, Cody Builders Supply, Sinclair, Carpi and Mach8Bio. Coordination and Partnering with the United States Forest Service.

Personnel: SFPUC – Regional Project Manager: Randy Anderson; Project Engineer: Joseph Buitrago; Acting Regional Construction Manager: Lucas Hoffman; Resident Engineer: Fredrick “Paco” Larsen; Public Outreach: Betsy Lauppe Rhodes and Jonathan Streeter; Delve – Project Manager: Troy Page; Design Project Manager: Renee Fippin, Principal: Tunnel Engineer: Glenn Boyce, Principal; AECOM – Contract Manager: Steven Tidwell, Vice President; Lead Inspectors: Kevin Bolle, Mark Loving, James Brown. Ron Smith and Jon Wolfe; Safety Manager: Rick Cavil, Environmental Compliance Manager: Tony Jones; Michels Tunneling – Project Manager: Jim Stevens; Construction Manager: Gabe McClain; Project Superintendent, Tyrone Wright.

Los Angeles

Purple (D Line) Extension Transit Project

The Purple (D Line) Extension Project is a 9-mile long project that consists of three Sections.
Section 1 is a 3.92-mile long subway alignment with three stations being constructed under Wilshire Boulevard in gassy ground and tar sands with prehistoric fossil deposits. It is being built by Skanska/Traylor/Shea JV under a $1.636 billion contract.

The $1.37 billion Section 2 project includes 2.6 miles of twin bore tunnel and two new stations and is being built by Tutor Perini/O&G.

Section 3 is a 2.6-mile extension being built by Frontier-Kemper/Tutor Perini JV under a $410 million contract for tunnel construction. Tutor Perini/O&G Joint Venture was awarded the Section 3 stations contract, which is valued at $1.4 billion and includes the construction of two new stations.
According to Metro, Section 1 is forecast to open in 2024, followed by Section 2 in 2025, and Section 3 in 2027.

San Jose

VTA’s BART Silicon Valley Phase II Project
Kiewit/Shea/Traylor

The completion of the project for the Santa Clara Valley Transportation (VTA) is currently being evaluated. The current estimated timeline has early construction activities begining in early 2024.

The Bay Area Rapid Transit (BART) Silicon Valley Phase II Extension (BSVII) Project is the second phase of VTA’s BART Silicon Valley Program to expand BART service into Santa Clara County. It is the largest single public infrastructure project ever constructed in Santa Clara County. The BSVII Project will extend the BART System from north San José through downtown San José to Santa Clara and is estimated to carry 54,600 passengers each weekday to destinations throughout the Bay Area by 2040. Completion of the project will finally “ring the bay” with frequent rail service.

The scope of the BSVII Project includes 5 miles of tunnel, 53.2-ft outside diameter and 48-ft inside diameter, and three underground stations. A fourth station, Santa Clara Station, and the Newhall Yard and Maintenance Facility are located at-grade at the west end of the BSVII extension in Santa Clara.

The project will be constructed within a variety of alluvial deposits that extend from the ground surface to depths of 300 ft. The deposits consist of non-sequential, laterally variable, interbedded, and discontinuous fine-grained and coarse-grained soils. Fine-grained soils include silts and clays and coarse-grained soils include sands and gravels.

The tunnel alignment will vary in depth from approximately at grade to 160-ft below the ground surface. The entire tunnel alignment will be below the groundwater table with pressures ranging from 1 up to 4.5 bar.
Kiewit/Shea/Traylor joint venture was awarded the Stage 1 Pre Construction Services contract to complete an innovations phase, programming services, engineering design services, open book cost estimating, and schedule development. The majority of these efforts are to be complete by June 2024.

Center Platform Stations
The station platforms will be housed within the bored tunnel at the Diridon, Downtown San José and 28th Street/Little Portugal stations. The majority of these stations are located along West Santa Clara Street. This approach also requires a series of adits to connect off-street surface access structures to the station platforms. The large diameter single bore approach standardizes station construction at all three stations along the CP2 alignment, eliminating the need for a long and deep open-cut, shored excavation along with minimizing utility relocation, support and local business interruptions.

Ventilation
The ventilation system proposed consists of a single point extraction system that relies on dampers and emergency ventilation stacks (EVS) spaced approximately 900 ft on center to remove smoke from the trainway in the event of a fire. The use of a precast concrete interior track slab supported by columns extending down to the tunnel invert instead of a track slab cast on structural fill within the tunnel, opened the invert area below the trainways to be used as a continuous ventilation plenum along the entire tunnel alignment. This continuous ventilation plenum allows for optimization of the fan locations and increases redundancy of the system.

Interior Build out – Precast track slab in bored tunnel.

This method proposes the use of an alternate precast track-support structure inside the bored tunnel, in lieu of a cast-in-place track slab on structural fill. This proposal, which employs a bridge-type structure to support BART trains, employs a multi-pronged approach to address the needs of emergency ventilation, seismic resistance, TBM service, access, and egress for construction materials in a manner that had not been previously contemplated. The use of precast elements allow for more efficient construction of elements off-site in a less constrictive environment that can then be transported to and assembled within the tunnel. Placement of precast elements in the tunnel will accelerate the overall construction process and reduce the amount of work needed to be completed in the tunnel (including logistics).

Project Parties: Kiewit Engineering Group – KIE, leads and manages design; Tunnel Designer: Arup; A joint venture of HNTB and WSP are providing program management services for the project and a Mott MacDonald/PGH Wong Engineering Inc. joint venture are providing General Engineering Services. Shannon & Wilson is the Geotechnical Engineer Consultant

Personnel: Project Director: Mike Colpack; Deputy Project Director: Kari Larsen; Project Construction Manager: Dave Hazen; Underground Construction Manager: Christof Metzger; Tunnel Interior Build Out Manager: Shemek Oginski; TBM Manager: Dick McLane, Pre-Construction Manager: William Searles; Estimating Manager: Tony O’Donnell; Design Director: Eric Halvorson; Deputy Design Manager: Kimball Olsen; Lead Tunnel Engineer, Commercial Manager: Brett Campbell.

COLORADO

Denver

PAR 1232 Second Creek Interceptor
Bradshaw Construction Corporation

Bradshaw Construction Corporation recently completed tunneling on the PAR 1232 Second Creek Interceptor project in Denver. The wastewater interceptor includes a number of trenchless crossings; of which Bradshaw Construction Corporation installed eight trenchless crossings, totaling over 4,100 lf, by the microtunneling method. Tunnel crossings ranged from 48-in. steel casing to 73.5-in. steel casing, with drive lengths reaching 1,500 lf on the longest crossing. FRP from 36 to 60-in. is being installed and backfilled once tunneling operations are completed. The tunnels were installed out of steel sheeted shafts, installed by Lawrence Construction Company. The challenging project geology consisted of multiple mix face conditions with claystone and sandstone overlaid by coarse and fine alluvium, underneath the water table. Tunnels passed underneath roads, highways, UPRR and BNSF tracks. To date, Bradshaw Construction Corporation has successfully completed the tunnel installations and is in the process of installing 36-in. FRP in the final tunnel.

The project members include Metro Wastewater Reclamation District (Owner), HDR Engineering, Inc. (Engineer), Garney Construction (CMAR), and Bradshaw Construction Corporation working as tunneling subcontractor.

Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

Denver

West Gates DIW Pond Expansion
Southland Contracting, Inc.

This unique project addresses Denver International Airport’s (DEN) most significant environmental risk, the discharge of aircraft deicing fluid to receiving waters. Southland Contracting (SCI) is constructing critically needed DIW infrastructure to allow the airport and their airline partners to continue operating during winter weather in compliance with environmental regulations. The new construction will provide volume for the current DIW storage deficit, and the ongoing 39-gate Concourse Expansion Program. Additionally, this project provides for future Deice Pads Delta Sierra (DS) West, DS East Deice Pads Delta (D), and apron expansion DIW runoff and collection storage.

The overall purpose of this $69.9 million project is to replace the existing DIW Pond 002. The tunnel scope of work consists of six bores totaling 5,179 lf. Each drive varies by length and diameter to accommodate the active runway, taxiways, and maintenance roads they cross.

Additional scopes of work include:

  • Four (4) 5.4-million-gallon pond cells (total of 21.6 MG of storage) located on the West Airfield
  • 4,400 lf of 72- and 90-in. FRP pipe to interconnect between existing Pond 002 and proposed Pond 002R
  • Diversion structures with gate valves
  • Pump Station with 4 pumps
  • 1-million-gallon DIW storage tank
  • 14-in. DIW force main to move collected DIW waters to the WADS Ponds or Lift Station No. 1 sanitary sewer system
  • Control facilities, along with needed infrastructure

Southland Contracting launched beneath Taxiway Whiskey Alpha (WA) / Bravo 4 (B4) in April 2023. A manned 60-in. diameter, Single Shield Tunnel Boring Machine (TBM) is excavating the 1,465 lf run for two-pass installation. This tunnel is supported by steel casing and will utilize one intermediate jacking station.

While the WA/B4 tunnel is under construction, SCI’s second tunnel crew began setup and excavation for a 43-ft deep launch shaft in May 2023. The 38-ft diameter launch shaft is supported by steel rib and wood lagging for a single-pass installation. This 550-lf drive, northwest of Taxiway Charlie November (CN), will be excavated using a manned 96-in. diameter Single Shield TBM. The single-pass installation will be completed with direct jacked FRP pipe. A 45-ft diameter common reception shaft will be installed and supported with steel beam and wood lagging. The common reception shaft will connect waste flow from the 550-lf, single-pass installation, to the downstream 2,051-lf drive crossing beneath Runway 16 Lima / 34 Romeo (16L/34R).

Following WA/B4 and CN completion, Maverick will mobilize to Runway 16L/34R for a two-pass 2,051-lf drive. Maverick is a manned 132-in. diameter, Single Shield TBM. The 132-in. diameter tunnel will carry a 72-in. DIW drain line, two 32-in. DIW High Concentrate drain lines, 8-in. Glycol Supply line, two 14-in. conveyance pipes, electrical and communication lines. This excavation will be supported with steel ribs and channel lagging. The 45-ft diameter common reception shaft depth will be 50-ft deep. Given the shallow depth at the launch location, trench boxes will be used for the launch pit.

The three remaining bores have been subcontracted to a local firm, Underground Infrastructure Technology (UIT). These bores range from 30- to 48-in. in diameter and total 1,113 lf. UIT mobilized for their first bore at 88th Avenue in May 2023.

The Contract Execution occurred on Nov. 30, 2022, with Notice to Proceed issued on March 1, 2023. Estimated completion is Q3 2024. Crews have completed 80 percent of the TBM excavation under Taxiway WA/B4, and have completed excavation of 2 of 4 pond cells.

Project Parties: Owner: City & County of Denver | Denver International Airport; Lead Designer: Burns & McDonnel, Inc.; Tunnel Designer: Lithos Engineering, Inc.; TBM Manufacturer: Southland Contracting, Inc.; Contractor: Southland Contracting, Inc.; Subcontractor: Underground Infrastructure Technology, LLC. (UIT); Contractor Design Engineer: Kilduff Underground Engineering, Inc.

Personnel: Area Manager: Nick Jencopale; Project Manager: Maxwell Pauley; General Superintendent: Jamie Willcott.

DISTRICT OF COLUMBIA

Washington

Northeast Boundary Tunnel (NEBT)
Salini Impregilo Healy JV (SIH JV)

The Northeast Boundary Tunnel (NEBT), the most recent of DC Water’s Clean Rivers Project, completed commissioning on Sept. 15, the agency reported.

The NEBT is 50-160 ft below ground and runs 27,000 ft from just south of Robert F. Kennedy Stadium to the intersection of Rhode Island Avenue NW and 6th Street NW. In times of flooding, the tunnel will receive flows from the sewer system captured by diversion facilities and convey them to DC Water’s Blue Plains Advanced Wastewater Treatment Plant.

The NEBT project also included the construction of ventilation control facilities, storm water inlets, and green infrastructure.

The NEBT is expected to reduce combined sewer overflows to the Anacostia River by 98 percent and the chance of flooding in the areas it serves from about 50 percent to seven percent in any given year.
Work began in September 2017 and was completed ahead of the Consent Decree schedule. The NEBT project, valued at $580 million, was built by Webuild Group and JV subsidiary Lane Construction.

INDIANA

Huntington

LTCP Projects 7 & 8, Northside Interceptor Sewer
Turn – Key Tunneling, Inc.

The City of Huntington came up with a long-term plan to eliminate combined sewer overflows and prevent raw sewage from spilling into local rivers and waterways. This pollution happens during times of intense rainfall or heavy snowmelt. This long-term plan is broken up into nine separate projects that will eventually keep local rivers cleaner and safer.

Turn – Key Tunneling, Inc. (TKT) was subcontracted by Atlas Excavating, Inc. for Projects 7 and 8 to install a 150-ft, 90-in. liner plate (provided by DSI Underground LLC) tunnel utilizing a tunnel shield approximately 15 ft deep. This liner plate tunnel will go underneath an existing Norfolk Southern Railroad. The tunneling will be conducted continuously, on a 24-hour basis, until the tunnel liner extends at least beyond the theoretical railroad embankment line with no stoppage. The $1.4 million project will be executed between Sept. 3, 2023, and Oct. 13, 2023.

To date, the tunnel liner plates are being installed in mixed face rock. Once the tunnel liner plates are installed, the exterior of the tunnel will be grouted via factory installed grout ports in the tunnel liner plates. Once the shield reaches the receiving pit and the contract footage has been installed, TKT will remove the tunnel shield and complete the carrier pipe installation.

Owner: City of Huntington; General Contractor: Atlas Excavating, Inc.; Tunneling Subcontractor: Turn – Key Tunneling, Inc.

Personnel: Chris Leonard – PM; Gary Ison – Superintendent; Domonic Thompson – Foreman; Monroe Miller – Foreman.

Indianapolis

Fall Creek Tunnel
Shea-Kiewit JV

The Fall Creek Tunnel is a 20,244-ft, 20-ft, 2-in diameter bored tunnel with an 18-ft finished concrete lining (approximately 250 ft deep). There are ten CSO connecting structures/deaeration chambers and adits. The work is for Citizens Energy Group’s DigIndy project, which is a CSO reduction program including six deep rock tunnels totaling over 28 miles.

Mining commenced in September 2019 and was completed on April 1, 2020. The Fall Creek Tunnel has nine adits totaling over 5,200 feet and adit and deaeration chamber excavation is 100% complete. Adit excavation is complete and chamber build out is ongoing. All drop and vent shaft excavation and lining is complete. Tunnel concrete lining operations and the retrieval shaft concrete lining is 100% complete. Surface connections are ongoing. Based on the terms of a federal consent decree, the Fall Creek Tunnel must be operational by the end of 2025.

Key Project Personnel – Construction PM: Christian Heinz, P.E.; Inspection PM: Sam Cain, P.E. (AECOM); Owner: Citizens Energy Group – Manager, DigIndy Capital Program: Mike Miller, P.E.; Tunnel Construction Supervisor: John Morgan.

Indianapolis

Pleasant Run Tunnel
Shea-Kiewit JV

The Pleasant Run Tunnel is a 41,472-ft, 20-ft, 2-in diameter bored tunnel with an 18-ft finished concrete lining (approximately 250 ft deep). There are eight CSO connecting structures/deaeration chambers and adits. The work is for Citizens Energy Group’s DigIndy project, which is a CSO reduction program including six deep rock tunnels totaling over 28 miles.

Mining commenced in May 2021 and was completed in August 2022. Drop shaft and vent shaft excavation and lining is ongoing. Adit and deaeration chamber excavation is complete, and crews have commenced lining and buildout. Tunnel concrete lining operations commenced in late April 2023 are approximately 20% complete. Surface connections are ongoing. Based on the terms of a federal consent decree, the Pleasant Run Tunnel must be operational by the end of 2025.

Key Project Personnel – Construction PM: Christian Heinz, P.E.; Inspection PM: Sam Cain, P.E. (AECOM); Owner: Citizens Energy Group – Manager, DigIndy Capital Program: Mike Miller, P.E.; Tunnel Construction Supervisor: John Morgan.

MARYLAND

MD2 at Samill Road Solomons Island
Turn – Key Tunneling, Inc.

Spring and Associates, Inc. was contracted by Maryland Environmental Services for the replacement of the storm drainage pipe at MD2 Samill in Calvert County. Due to the pipe size, total length, and limited space for a driving pit, a 72-in. tunnel utilizing a hydraulically driven tunnel shield and liner plate became the appropriate method for this project.

Turn – Key Tunneling, Inc. (TKT) was subcontracted by Spring and Associates, Inc. to construct the 72-in. tunnel liner plate underneath MD2/Solomons Island Road. This liner plate tunnel will be constructed for the replacement of approximately 261 lf of 42-in. RCP drainage pipe. TKT’s work also entails constructing a backstop capable of withstanding the jacking load, threading the carrier pipe into the TLP on rails, and backfilling the annular space with grout. Once the contract footage has been installed, the tunnel shield used for this project will be removed and the threading and filling will commence.

The bid price was $947,420. Construction was expected from June 20, 2023 to Oct. 15, 2023.

Owner: Maryland Environmental Services; General Contractor: Spring and Associates, Inc.; Tunneling Subcontractor: Turn – Key Tunneling, Inc.

Personnel: Chris Leonard – PM; Gary Ison – Superintendent; Jake Vanover – Foreman.

NORTH CAROLINA

Charlotte

Dairy Branch Tributary
Bradshaw Construction Corporation

Bradshaw Construction Corporation has completed construction on sanitary sewer tunnels in Charlotte. The 2,399-ft by 60-in. steel casing tunnel was installed behind a Herrenknecht AVN-1200 MTBM for a 36-in. PVC sanitary sewer. Subsurface conditions consist of granitic rock ranging from 25 to 38 kpsi and alluvial deposits. Construction started in November 2020 and has completed the 2,399 ft of total tunnel. The project members include Charlotte Water (Owner), STV Engineers, Inc. (Engineer) B.R.S., Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.

Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

Charlotte

Little Sugar Creek Tributary to Central Business District
Bradshaw Construction Corporation

Bradshaw Construction Corporation has completed construction on one-pass sanitary sewer tunnels in Charlotte. The 3,587-ft by 48-in. reinforced concrete pipe tunnel will be installed behind a Herrenknecht AVN-1200 MTBM. Subsurface conditions consist of granitic rock ranging from 9 to 30 kpsi and alluvial deposits. Construction began in September 2020 and has completed the 3,587-ft of tunnel. The curved tunnels are the first planned direct jack curved sanitary sewer in North Carolina. The project members include the Charlotte Water (Owner), WSP USA (Engineer) Sanders Utility Construction Co., Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.

Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

Charlotte

Upper Little Sugar Creek Trunk Sewer Improvements
Bradshaw Construction Corporation

Bradshaw Construction Corporation has started construction on one pass sanitary sewer tunnels in Charlotte. The 2,272-ft by 72-in. reinforced concrete pipe tunnel will be installed behind a Herrenknecht AVN-1800 MTBM along curved alignments. Subsurface conditions consist of partially weathered rock and alluvial deposits. Construction began in November 2021 and has completed 1,177 ft of the 2,272 ft for the project. The second tunnel on the project has been redesigned to incorporate a 10-ft x 10-ft horseshoe drill and blast to mitigate exposure to hard granitic rock. The project members include Charlotte Water (Owner), Kimley & Horn (Engineer) Sanders Utility Construction Co., Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.

Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

Raleigh

West Neuse Interceptor Improvements
Bradshaw Construction Corporation

Bradshaw Construction Corporation has started construction on two-pass sanitary sewer tunnels in Raleigh. The 580-ft by 87.5-in. steel casing to allow for the installation of proposed 66-in. sanitary sewer will be installed behind a Herrenknecht AVN-1800 MTBM. The first 196 ft out of 580’ ft has been installed. Subsurface conditions consist of granitic rock. Construction began in March 2023. The project members include Raleigh Water (Owner), Black & Veatch (Engineer) JF Wilkerson Contracting Co. Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.

Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

OHIO

Cleveland

Shoreline Storage Tunnel
McNally – Kiewit

The contractual completion date for this $201.58 million project is May 2026. The anticipated completion date is December 2025. It is part of Project Clean Lake for the Northeast Ohio Regional Sewer District.
The Shoreline Storage tunnel is a 14,200-ft, 26-ft excavated/23-ft finished EPBM tunnel for combined sewer overflow, storage, and conveyance. It is approximately 100 ft deep running parallel to Lake Erie’s shoreline in Cleveland. The Shoreline Tunnel System will reduce CSO by an estimated 350 million gallons annually from 12 permitted CSO locations that are direct tributaries to Lake Erie. NTP was issued on July 19, 2021, with a duration of 1,770 days. The project consists of the main tunnel as well as a 70-ft of 78-in. diameter dewatering sewer, 50-ft of 84-in. diameter consolidation sewer, three shafts, numerous near-surface structures, and repairs to existing sewers and regulators.

All 3 shafts have been excavated and the TBM has been launched. The project team is working to complete the drive between shafts SST-1 and SST-2. The final lining concrete is being placed in SST-3 as some of the diversion structures are being excavated and eventually tied into.

Unique features of this job include 6-ft precast tunnel liner rings and EPBM in soft ground, starting in glacial till, until eventually transitioning to sandy lenses with 75% of drive in clays.

Delve Underground is the tunnel designer. The TBM manufacturer is Herrenknecht.

OKLAHOMA

Edmond

Arcadia Intake
Southland Contracting / Oscar Renda Contracting JV

The Arcadia Intake for the City of Edmond is a $68 million project comprising three microtunnels launched from a single shaft. The Shaft is 54-ft ID and 80 ft deep, built with 80, 1-m diameter secant piles.

The tunnels include:

  • Upper Intake, 150 ft long, 16 ft below lake normal pool elevation
  • Middle Intake, 250 ft long, 30 ft below lake normal pool elevation
  • Lower Intake, 450 ft long, 40 ft below lake normal pool elevation

The tunnels will include wet retrievals and will serve as intakes for the city’s new water supply system. NTP was issued in November 2022, with completion anticipated by April 2025.

The MTBM entry seals will be cast in 2 ft thick final concrete liner. Entry seals have 72-in. flanges, on which slide gates will be installed once tunneling is complete. Crews will use 60-in. Permalok jacking pipe with ¾-in. wall. Tee screens with airburst system will be installed on end of HOBAS pipe.

5 each 150- to 300-hp vertical turbine pumps will sit on elevated slab over shaft, suction tubes (column pipes) will extend to floor of shaft with bowl assemblies 75 ft below pump room floor. The pump station will be encapsulated by precast building.

Currently, the marine subcontractor is installing screen foundations. Concrete shaft concrete lining is complete, and crews are setting up for upper intake tunnel excavation.

The project marks the first lake tap wet retrieval in the United States using FRP Pipe. A Herrenknecht AVN1200 machine will be used including an upskin kit with a subsea recovery can and hard rock cutterhead. Excavated material will consist of sandstone, claystone and mudstone in undisturbed earth, and alluvial fill with lakebed.

Owner: City of Edmond Public Works Authority; Owners’ CM/Engineering Manager: Carollo Engineers; Engineer of Record: Schnabel Engineering; General Contractor: Oscar Renda Contracting; Tunnel Contractor: Southland Contracting, Inc.; TBM Manufacturer: Herrenknecht, Southland Contracting.

Personnel: SCI Project Manager: Elliott Fuller; SCI Survey Manager: Fareed Imoro; SCI Field Engineer: Kash Sisk; SRJV Senior Project Engineer: Kyle Crawford; SRJV Superintendents: Homero Lugo, Shane Sorteberg.

TEXAS

Carrollton

DWU Elm Fork 72-in. Water Main
Southland Contracting / Oscar Renda Contracting JV

This $44 million project for Dallas Water Utilities includes 8,600-lf of tunneling including three reaches at 10-ft excavated diameter. Crews used a TBM manufactured by Southland Contracting. The TBM is a double-shielded, open-faced, gripper type machine with articulated steering. The tunnel is supported by rib and board and will house 72-in. steel carrier pipe. The project includes five shafts, 18 to 35 ft in diameter and 75 to 96 ft deep. Shafts are supported by ring beams and liner plate and rock bolts and shotcrete within the Eagle Ford shale.

All shafts and tunnels have been excavated and 7,100 ft of carrier pipe has been installed and backfill grouted, with 1,500 ft remaining. Two shafts have been backfilled with manholes and pipe installed.
A 20-ft diameter shaft was added by owner due to change in permanent configuration. The shaft has been excavated 60 vf of proposed 70 vf. Anticipated final completion is March 2024.

The project was re-designed post-bid by the Southland Contracting team. Contractors’ opportunity for re-design was described in original contract documents. The original design required open-cut pipeline installation with invert depths ranging from 18 to 30 vf where overburden material was primarily small-particle sand with groundwater.

The original design required a 2,000 ft curved microtunnel drive along railroad. Through coordination with Dallas Water Utilities and AECOM, the pipeline elevation was lowered, and access manways and appurtenances were added for its installation in a deep tunnel. Two of five shafts are within Railroad ROW. Special design and coordination were required pre-construction. Settlement monitoring is required daily.

Project Parties: Owner: Dallas Water Utilities; Engineer & CM: AECOM; Tunnel Designer: Brierley Associates; General Contractor/Program Manager: Oscar Renda Contracting; Tunnel Contractor: Southland Contracting, Inc.; TBM Manufacturer: Southland Contracting.

Personnel: SRJV Project Manager: Elliott Fuller; SRJV Construction Manager: Clay Griffith; SRJV Senior Project Engineer: Fareed Imoro; SRJV Superintendent: Otillio Ramos.

Dallas

Mill Creek/Peaks Branch/State Thomas Drainage Relief Tunnel Project
Southland/Mole Joint Venture

This $206 million project for the City of Dallas involves the construction of 26,385 lf of tunnel (32-ft, 6-in. excavated diameter, 30-ft finished diameter), eight intake shafts (ranging from 120 to 200 vf) and six lateral tunnels excavated by roadheader or excavators/breakers. The tunnel was driven by a Main Beam TBM through primarily Austin chalk.

Crews have completed excavation of eight shafts ranging from 22 to 35 ft in diameter and 110 to 190 ft deep, as well as excavation six lateral tunnels, with the final lateral tunnel near completion. These range from 12.5 to 25 ft in diameter and 50 to 500 ft in length.

TBM mining was completed in July 2022. Mining included 26,000 lf of tunnel excavation completed at 37-ft, 7-in. OD (10,000 lf) and as well as 32-ft, 6-in. OD (16,000 lf) with a diameter change to the smaller size mid-drive.

Crews have completed demobilizing the TBM and have mobilized formwork and equipment for cast-in-place tunnel concrete lining operation for the 30-ft ID, 15-in. thick final lining. CIP lining is ongoing at multiple lateral and shaft locations.

Owner: City of Dallas; Lead Designer: HALFF; Tunnel Designer: COWI; CM: Black and Veatch; TBM Manufacturer: The Robbins Company; Contractor: Southland Mole JV (Southland Contracting & Mole Constructors); Subcontractor: Oscar Renda Contracting, Inc.; Contractor Design Engineer: Aldea Services.

Personnel: SMJV Senior Project Manager: Quang D. Tran, P.E.; SMJV Senior Project Manager: Nick Jencopale; SMJV Project Manager: Jose Ortiz, P.E.; SMJV Surface PM: Caesar Ramirez; SMJV Safety Manager: Stephen Jones; SMJV Senior Project Engineers: Matt Jackson/Jason Lipp; SMJV General Superintendent: Jose Jimenez/Mike Clingon; SMJV Project Engineers: Liany Marino.

Frankston

PL-19 Long Tunnel Crossings
Bradshaw Construction Corporation

Bradshaw Construction Corporation is continuing work on 84-in. steel water line project in Frankston, which consists of two tunnels, spanning 1,712 lf. The tunnels are split up into a 903-lf drive, and 809-lf drive, which will both be mined utilizing 99.5-in. steel casing behind a Herreknecht AVND 1800AB MTBM. Bradshaw is currently finished mining the longer of the two tunnels, which had encountered layers of clayey Queens City sand that transitioned into sandy Queens City sand. The tunnel was mined out of a 38-ft rib and liner plate shaft with little evidence of ground water. The second of the two tunnels is 50 miles southwest of Frankston, and was launched out of a secant pile shaft. The tunnel has since mined under the Union Pacific railroad, and is currently 40 ft from complete. During the drive, the MTBM has mined mostly through the clayey Wilcox Group, but has recently transitioned to a sandy fluviatile deposit. It was anticipated that both tunnels would be completed and grouted by the end of September 2023. Project members include Tarrant Regional Water District (Owner), Brierley Associates (Engineer) and Traylor-Sundt Joint Venture (General Contractor), with Bradshaw Construction performing as the microtunneling subcontractor.

Information: Chris Flanagan – Project Manager; CFlanagan@bradshawcc.com.

VIRGINIA

Alexandria

RiverRenew Tunnel
Traylor-Shea

The RiverRenew Tunnel System Project includes a 2-mile-long, 12-ft-wide tunnel, shafts, and other sewer infrastructure that will help prevent about 130 million gallons of sewage from polluting the Potomac River, Hunting Creek, and Hooffs Run each year. Traylor-Shea was awarded a $454.4 million contract to complete the final design and construct the Tunnel System Project. The Traylor-Shea design-build team consists of Traylor Bros, Inc., and J.F. Shea Co., a joint venture, with support from Jacobs Engineering and Corman Kokosing Construction Co.

The Herrenknecht tunnel boring machine (TBM) began mining on Nov. 1, 2022, and reached the first of two outfall sites in June 2023. Boring of the Waterfront Tunnel is expected to continue through December 2023. The project also includes the Hoofs Run Interceptor, that will be excavating using a Herrenknecht 76-in. MTBM.

Project completion is expected by July 2025.

Designer: Jacobs Engineering; Construction Manager: Brown & Caldwell, JCK Underground, EPC; Major Subcontractors: Kokosing Industrial, Keller North America; TBM Manufacturer: Herrenknecht AG.

Front Royal

Parallel Waterline for the Route 522 North Corridor
Bradshaw Construction Corporation

Bradshaw Construction Corporation will soon begin construction for a tunnel installation on the Parallel Waterline for the Route 522 North Corridor project in Front Royal. Bradshaw will install a 552-ft, 60-in. steel casing tunnel underneath the Shenandoah River out of 55-ft deep liner plate shafts installed by the General Contractor. 18-in. DIP waterline will be installed by the General Contractor after the tunnel is completed. Ground conditions will be massive limestone up to 20 ksi with the potential for karst features. The project members included the City of Front Royal (Owner), CHA Consulting Inc. (Engineer), Snyder Environmental, Inc. (GC), and Bradshaw Construction Corporation working as the tunneling subcontractor.

Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

Newport News

46th Street Diversion Sewer
Bradshaw Construction Corporation

Bradshaw Construction Corporation will soon begin work on the 46th Street Diversion Sewer Rehabilitation/Replacement project in Newport News. The project includes two tunnels totaling approximately 400 ft LF of 43-in. steel casing. The drives will be launched out of a common liner plate launch shaft installed by the General Contractors’ subcontractor at the intersection of 33rd Street and West Avenue. Ground conditions are expected to include poorly graded sand for the drive along West Avenue and fat clay for the drive along 33rd Street. Key project members include Hampton Roads Sanitation District (HRSD) (Owner), Ramboll Americas Engineering Solutions Inc. (Engineer), Tidewater Utility Construction, Inc. (General Contractor), and Bradshaw Construction Corporation as the tunneling subcontractor.

Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

Newport News

Jefferson Avenue Interceptor Force Main Replacement Phase III
Bradshaw Construction Corporation

Bradshaw Construction Corporation recently completed a tunnel installation for the Jefferson Avenue Interceptor Force Main Replacement project in Newport News. The 36-in. HDPE force main will be installed by the General Contractor in the completed 60-in. steel casing tunnel, 540-ft long passing underneath of I-64 and a canal. The tunnel was launched out of and recovered into steel sheet shafts installed by the General Contractor. Ground conditions included predominantly clay with sand, beneath the water table. The project members included the Hampton Roads Sanitation District (HRSD) (Owner), RK&K (Engineer), Bridgeman Civil Inc. (GC), and Bradshaw Construction Corporation working as the tunneling subcontractor.

Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

Norfolk

Hampton Roads Bridge-Tunnel
Hampton Roads Connector Partners

With a budget of more than $3.8 billion, the Hampton Roads Bridge-Tunnel (HRBT) Expansion project for the Virginia Department of Transportation is the largest highway construction project in the state’s history. The project involves widening the current four-lane segments along nearly 10 miles of the I-64 corridor in Norfolk and Hampton, with new twin tunnels across the harbor. The expansion will increase capacity, ease major congestion and enhance travel time reliability.

The new tunnels will be bored with a 46-ft diameter variable-density Herrenknecht TBM, 50 ft deeper than the existing tunnels. The project represents only the fourth TBM-bored highway tunnel in the United States (Port of Miami Tunnel, Seattle SR 99 Tunnel and the Parallel Thimble Shoal Tunnel in Virginia are the others), and the second largest TBM used in the country (behind SR 99).

In addition to new tunnel construction, the project involves replacing/building bridge structures (five bridges to be replaced, 23 to be widened), replacing marine trestles and widening of the roadway from two to three lanes in each direction.

In early 2019, VDOT entered into a P3 design-build contract with Hampton Roads Connector Partners to build the project. Hampton Roads Connector Partners includes Dragados USA (lead contractor) and HDR and Mott MacDonald (lead designers). Also on the joint venture team are Flatiron Constructors, Vinci Construction and Dodin Campenon Bernard.

The TBM had mined nearly 1,700 ft as of the end of September, according to WAVY. Project completion was expected in 2025.

Norfolk

Parallel Thimble Shoal Tunnel
Dragados USA/Schiavone Construction

The $756 million project entails the construction of a 5,700-ft bored tunnel connecting two southbound trestles of the existing Chesapeake Bay Bridge and Tunnel, a 17.6-mile structure connecting the Norfolk/Virginia Beach areas to Virginia’s eastern shore which first opened to traffic on April 15, 1964. When complete, the new tunnel will carry two lanes of traffic southbound and the existing tunnel will carry two lanes of traffic northbound.

On Feb. 21, 2023, the 43.5-ft diameter TBM began its initial excavation at the tunnel’s headwall, marking the official start of tunneling for the Parallel Thimble Shoal Channel Tunnel. WAVY reported that tunneling was stopped due to encountering an anchor while mining. Tunneling is expected to resume in February 2024, with project completion forecast for May 2027.

Richmond

Chimborazo Drop Shaft and Sanitary Sewer Replacement
Bradshaw Construction Corporation

Bradshaw Construction Corporation has completed work on a sanitary sewer replacement project in downtown Richmond, which consisted of four shafts and two tunnels. The four shafts were comprised of two 33-ft x 21-ft ellipse liner plate launch shafts and two 23-ft diameter recovery shafts, the deepest of which is 104 ft. The two tunnels span a combined distance of 594 lf, which utilized 78-in. Permalok steel casing behind a skinned-up Herrenknect AVN-1500. While excavating one of the recovery shafts, it was determined the ground conditions varied from the geotechnical report when large boulders were observed at tunnel elevation. Because of this Bradshaw opted to equip the AVN 1500 with a rock cutter head for that particular tunnel, which totaled 331 ft. The other shafts showed zero evidence of boulders, and a soft ground cutter wheel was utilized to mine clayey sand and elastic silt. Once both tunnels were completed, 60-in. DI sewer pipe was installed within the casing on stainless steel casing spacers. The project members include the City of Richmond (Owner), Greeley and Hansen (Engineer) and Southwood Building Constructors(General Contractor), with Bradshaw Construction performing as the shaft and tunneling subcontractor.

Information: Chris Flanagan – Project Manager; CFlanagan@bradshawcc.com.

WASHINGTON

Seattle

Ship Canal Water Quality project
LANE Construction

The $255 million Ship Canal Water Quality Project (SCWQP) Storage Tunnel Contract for Seattle Public
Utilities (SPU) is comprised of 13,939 lf of 18-ft, 10-in. ID segmentally lined tunnel using a 21.5-ft diameter pressurized face tunnel boring machine (TBM) with tunnel depths ranging from 35 to 85 ft to top of tunnel, and a conveyance pipe casing under the Ship Canal installed via a curved microtunnel drive, 646 lf and 94-in. diameter.

There are five shaft sites: one slurry wall shaft at the West Shaft site in Ballard (tunnel launch site); three secant pile shafts at the Fremont site, Queen Anne site, and East Shaft site in Wallingford (tunnel exit shaft); and one drilled shaft using a steel casing at the East Ballard site. Anticipated ground conditions along the tunnel alignment consist of a highly variable mix of glacially over-consolidated soils.

When completed, the tunnel will capture and temporarily store more than 29 million gallons of untreated stormwater and sewage until the treatment plant is ready for it. The tunnel will improve water quality regionally by keeping more than 75 million gallons of polluted stormwater (from rain) and sewage each year from flowing into the Lake Washington Ship Canal, Salmon Bay, and Lake Union.

The project is a joint effort between two agencies: Seattle Public Utilities (Lead) and King County Wastewater Treatment Division. Both Agencies are under Consent Decree with the US EPA and DOJ, and the Washington State Department of Ecology to have the SCWQP in service by the end of 2025. The Storage Tunnel is the second of four projects in the SCWQP. There are two subsequent projects to connect the new storage facility to the local sewer systems to complete the SCWQP.

The construction project is 85% complete (as of the end of August 2023). Tunnel mining was completed in July. The 21.5-ft diameter TBM, (“Mudhoney”), completed 13,947 ft of the tunnel drive that began in the Ballard neighborhood and traveled eastward along the north side of the Ship Canal to the Wallingford neighborhood. The 10-ft diameter MTBM also completed its journey from Fremont southward under the Ship Canal toward the Queen Anne neighborhood in March 2023. Crews then installed conveyance pipe and below grade vaults at four sites along the tunnel route.

The Herrenknecht EPB TBM has performed well through very variable ground conditions with minimal surface settlement, including passing directly underneath the footings of the approach span to Ballard Bridge.

Lane successfully introduced the use of a pressurized launch bell into the USA and the TBM overcame two significant challenges – drilling through a very large boulder, and passing through 19 de-tensioned cable tiebacks. Production statistics include 96.5 ft in one day, 390 ft in a week and 1,291 ft in a month.

Tunnel Designer: Delve Underground (formerly McMillen Jacobs Associates); Construction Manager: Jacobs Engineering; TBM Manufacturer: Herrenknecht. Major Subcontractors: Shaft Construction – Malcolm Drilling Co.; Microtunneling – Northwest Boring Co. Inc..; Mechanical and Concrete Structures – Prospect Construction Inc.; Electrical – Chau Electric; Trucking – Grady Excavating Inc.; Segments: CSI.

Personnel: Owner (SPU): Keith Ward: SCWQP Executive; Cynthia Blazina: SCWQP Construction Manager; Stephanie Secord: SCWQP Project Manager; Roger Mitchell: SCWQP Supervising Resident Engineer. Lane Construction: Daniele Nebbia: Vice President of Tunneling Operations; Project Director: Fabrizio Fara; Project Manager: John Arciszewski; Technical Manager: Francesco Chiappalone.

CANADA

BRITISH COLUMBIA

North Vancouver

Second Narrows Water Supply Tunnel Project – Burrard Inlet Crossing
Traylor Aecon General Partnership

Metro Vancouver is constructing a new $286 million water supply tunnel deep under Burrard Inlet, east of the Ironworkers Memorial Bridge between the District of North Vancouver and the City of Burnaby. The project includes the 1.1-km tunnel, two shaft and near-surface structures (valve chambers).

This project is one of five new regional water supply tunnels that are being designed to meet current seismic standards to ensure the reliable delivery of drinking water in the region in the event of a major earthquake. When complete, the tunnel will also increase the capacity of the existing system to meet the long-term needs of the growing population.

Tunnel excavation, pipe installation and backfill are complete. Shaft pipe installation and near surface valve chamber construction are underway.

The project team used a 7-bar pressure slurry (Mixshield) TBM– a first for a metro sized tunnel in Canada.

Project team: Traylor Aecon General Partnership: Contractor; Metro Vancouver: Owner; Delve Underground: Tunnel and Shafts Designer; AECOM: Near Surface Works Designer; Mott MacDonald: Construction Manager; Herrenknecht: TBM Manufacturer; Southwest Contracting: Earthworks Subcontractor; Jewel Holdings: Pipe Welding and Coating Subcontractor; Aecon Water: Large Bore Mechanical Installation Subcontractor; Black & McDonald: Electrical, Instrumentation, HVAC, and Fuel Oil Subcontractor; Nucor-Harris Rebar: Reinforcing Steel Subcontractor.

Personnel: Construction Manager: Patrick Hamlin (Mott McDonald); Engineer of Record: Andrew McGlenn (Delve); Owner’s Representative: Mark Qian (Metro Vancouver); Project Manager: Erica Frederickson (Traylor); Project Engineer: Brian McInnes (Aecon); General Superintendent: Ty Winters (Traylor).

ONTARIO

Ottawa

Stage 2 LRT Project – Confederation Line East and West Extension Project
East-West Connectors (EWC)

The Stage 2 Confederation Line East and West Extension Project is a $2.57 billion (CAD) design-build-finance project for the City of Ottawa being built by East-West Connectors (EWC), a joint venture comprised of Kiewit, Eurovia and VINCI (KEV).

The Stage 2 O-Train East and West extensions are a signature project in Canada’s national capital, funded by three levels of government. There is a strong focus to ensure that the project is delivered with minimal impact on the community. This requires close, on-going engagement with stakeholders and the public, as building a large infrastructure project in an urban environment is disruptive.

The West extension includes two cut-and-cover tunnels:

The 3-km Parkway Tunnel will travel between Kìchì Sìbì and Lincoln Fields stations traveling underneath the Kichi Zībī Mīkan (formerly Sir John A. Macdonald Parkway), Richmond Road, and Byron Linear Park.
The 270-m Connaught Tunnel will link south of Lincoln Fields Station with Queensview Station by traveling underneath Connaught Avenue and connecting with the Pinecrest trench.

Construction of the Parkway Tunnel began in 2020, and at the end of July 2023 it was 71% complete. Construction of the Connaught Tunnel began in 2021, and at the end of July 2023 it was 62% complete. The structural work for both is expected to be fully completed at the end of 2024. The Parkway Tunnel will travel through federal lands and a City of Ottawa linear park to preserve recreational opportunities and community linkages. When construction is complete on the Parkway Tunnel, Byron Linear Park will be enhanced to include more trees, less pavement, more public art, and additional plaza space for local events. The Connaught tunnel will travel through a residential neighborhood.

To optimize the building sequence, the structures team is utilizing three Everest Traveler formwork systems to pour the three walls of the tunnel and roof together on the Parkway Tunnel. This is a hydraulic system that allows the team to pour 250 cubic meters of concrete every 10 days. The Everest needs to be modified at certain points due to the alignment of the cut and cover tunnel. The structures team is also using two Peri Traveling Formwork systems, which perform the same functions as the Everest Traveler but in less uniform spaces pouring the walls and roof separately.

Design engineering services for the Stage 2 Confederation Line East and West Extension Project are being provided by WSP Canada and Hatch Ltd.

Personnel: Alex Saltarelli, Project Director, East-West Connectors GP.

Ottawa

Stage 2 LRT Project – O-Train South Extension Project
TransitNext

Dow’s Lake Tunnel is being rehabilitated as part of the Stage 2 O-Train South Extension. Located under Dow’s Lake, the tunnel is 578 m long and first opened in 1967.

The tunnel is reinforced with 23 concrete box segments separated by 22 expansion joints. The height of the tunnel is approximately 6.7 m from the top of the rail. The width of the tunnel is approximately 5.1 m.
In August 2023, the physical works in the tunnel were approximately 95% completed. This number was expected to reach 100% by Q3 2023, after which works in the tunnel will shift to the testing and commissioning of the new passenger rail system.

Work s currently underway commissioning the tunnel ventilation system, extending standpipe system, testing communication systems, to align with National Fire Protection Association (NFPA) -130 standards.
Mechanical systems in the tunnel including the installation of 18 jet fans for ventilation, and 22 expansion joint drip pans to channel water infiltration to the trench have been completed. The tunnel standpipe system has been partially upgraded and will be ready for testing by Q3.

Fiber optic cable and radiating cables are being installed to provide cellular service in the tunnel.
Some of the remaining works include testing and commissioning of communications systems, train testing within the tunnel, emergency scenario testing, ventilation system testing, and installation of emergency stairs.

There are some interesting safety features about the tunnel, including three safety bays, which are cut outs within the tunnel walls that have emergency telephones directly linked to Ottawa Fire Services. Concrete curbs run on either side of the rails the length of the tunnel and house a heat trace to help deal with Ottawa’s harsh winter conditions. One side of the curb is wider than the other, which allows for a dedicated emergency egress route.

Toronto

Ashbridges Bay Treatment Plant Outfall
Southland | Astaldi JV

The $300 million Ashbridges Bay Treatment Plant Outfall for the City of Toronto is 90 percent complete with final completion expected by November 2024.

The project comprises:

  • 16-m diameter shaft, 85 m deep
  • 3.5 km of 8-m diameter TBM excavated tunnel
  • 7-m ID precast concrete segmental lining
  • 50 of 1-m diameter risers from tunnel (marine work)
  • CIP structure at top of shaft
  • Ground expected: Georgian Bay shale

Shaft excavation, tunneling offshore risers and riser connections are complete, with effluent conduit structure construction underway.

Owner: City of Toronto; Contractor: Southland | Astaldi JV; Consultant & Designer: Hatch with Jacob & Baird; Major Subcontractors: Johnson Bros. Corp (Off-shore work including Riser installation).

Personnel: Contractor: Southland | Astaldi JV; Project Executive (Kent Vest); Project Director (Joe Savage); Project Manager (Pouya Mirhashemian); Deputy Project Manager (Christian Zenck); General Superintendent (Curtis Bahten); Underground Superintendent (Jeff Reagan).

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