Tunnel Updates

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 February 2023 issue of the print edition.

Joint Water Pollution Control Plant Effluent Outfall Tunnel Dragados USA

The Los Angeles County Sanitation Districts (Sanitation Districts) are undertaking the $630.5 million Joint Water Pollution Control Plant Effluent Outfall Tunnel project (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.

As part of the implementation of the Clearwater Program, the Sanitation Districts will construct 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 will be constructed by slurry TBM beginning at the JWPCP Shaft Site (entry shaft) and ending at Royal Palms Beach (exit shaft). The tunnel alignment will vary 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 very distinct ground conditions. The first half of the tunnel will be through soft ground with depths up to 110 feet. The second half of the tunnel will be through hard rock with depths up to 450 feet where the tunnel will be subjected to intense ground squeezing conditions due to the overburden pressure.

The tunnel lining will consist of bolted and gasketed precast concrete segments. Tunneling will go through splays of the Palos Verdes Fault Zone where 16-foot diameter steel liner will be used within the 18-foot 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 the summer of 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-foot 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. Two planned maintenance stops at Safe Havens 1 and 2 were also completed. Approximately 9,300 ft of tunnel lining has been installed to date.

Lead Design Consultant: Parsons; Tunnel Design Consultant: McMillan Jacobs Associates; 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 – Daniel McMaster, Lead Tunnel Consultant. Dragados – Claudio Cimiotti, Project Manager; John Truong, Deputy Project Manager; Nicholas Karlin, Project Engineer.

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 linear feet of new concrete invert paving, demolition of existing bulkheads and installation of new bulkheads, bulkhead improvements and debris removal. Construction of new tunnel improvements 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 1000-foot-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 35% complete. Waterproofing and CIP final lining was completed in the bottom portion of the FCF shaft. Large diameter steel piping was installed and backfilled in the upstream and downstream bypass tunnels. A bulkhead door and frame were installed in the Priest adit and successfully pressure tested. In preparation for the upcoming outage a temporary water filtration system was installed at Moccasin and a construction water treatment plant was set up at Priest. Work continues for the many road improvements along the 19-mile project corridor.

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 in order 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 McMillen Jacobs Associates, 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 Apex Rockfall Mitigation, Kroner Environmental, Schrader Mechanical, Cody Builders Supply, Sinclair and Mach8Bio

Key Project 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; McMillen Jacobs and Associates – Project Manager: Jennifer Sketchley, Associate; 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 and Jon Wolfe; Safety Manager: Rick Cavil; Michels Tunneling – Project Manager: Jim Steven; Tunneling Managers: David McCallum and Gabe McClain; General Superintendent, Tyrone Wright.

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) will construct 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 linear feet. Each drive varies by length and diameter to accommodate the active runway, taxiways, and maintenance roads they cross. Based on geotechnical reporting by Lithos Engineering, SCI anticipates claystone and sandstone bedrock to be encountered in shaft and tunnel excavations along with cohesive soils consisting of lean clay with varying amounts of sand and clayey sand.

Additional scopes of work include:

Southland Contracting will first launch beneath Taxiway Whiskey Alpha (WA) to cross Deicing Pad WA and Taxiway Bravo 4 (B4). This 1,465 linear foot, two-pass installation, will be excavated using a manned 60-inch diameter, Single Shield Tunnel Boring Machine (TBM). This tunnel will be supported with steel casing and utilize one intermediate jacking station. Given the shallow depth at this location, trench boxes will be used for both launch and reception pits.

Following Taxiway Whiskey Alpha, SCI will excavate a 43-ft deep launch shaft supported by steel rib and wood lagging for a single-pass installation. This 550 linear foot drive, northwest of Taxiway Charlie November (CN), will be excavated using a manned 96-inch diameter Single Shield TBM. The single-pass installation will be completed with direct jacked FRP pipe. A 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 linear foot, single-pass installation, to the downstream 2,051 linear foot drive crossing beneath Runway 16 Lima / 34 Romeo (16L/34R).

The 2,051 linear foot drive will be excavated using a manned 132-inch diameter, Single Shield TBM, for two-pass installation. The 132-in. diameter tunnel will carry a 90-in. DIW drain line, 24-in. DIW High Concentrate drain line, 8-in. Glycol Supply line, two 14-in. conveyance pipe, electrical and communication lines. This excavation will be supported with steel ribs and channel. The 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. diameter and total 1,113 linear feet.

Status of Project:

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: VP of Operations: Kent Vest; Area Manager: Nick Jencopale; Project Manager: Maxwell Pauley; General Superintendent: Joe Vera.

Chimney Hollow Reservoir – Inlet/Outlet Tunnel Barnard Construction Company, Inc.

Barnard Construction is the general contractor performing work at the Chimney Hollow Reservoir Project. As part of this project, Barnard is self-performing construction the Inlet/Outlet Tunnel, which started in April 2022.

The purpose of the tunnel is to carry a 6-ft. diameter steel welded pipe for water transmission underneath Chimney Hollow's main dam. Called Inlet/Outlet, or I/O for short, the tunnel's steel pipe will transport water to fill the future Chimney Hollow Reservoir, and deliver the reservoir water when needed through the same steel pipe. An inlet/outlet tower will be constructed in the upstream portal and connects to the tunnel's steel pipe. The tower and portal sit at the bottom of the reservoir footprint at the upstream toe of the dam.

The pipe exiting the tunnel on the downstream side is entrenched and connects to the project's Valve House which ultimately controls the water flowing into, out of, and bypassing the reservoir. When water is drained from the reservoir, it will flow through the tower, into the steel pipe in the tunnel, to the Valve House, and connects with existing infrastructure owned by both the U. S. Bureau of Reclamation and Northern Colorado Water Conservancy District to provide water to the project's 12 regional participants.

This unique 2,000-ft. long tunnel includes 4 separate excavation profiles including a 26-ft. horseshoe/circular shaped 667-ft. long downstream tunnel, a 30-ft. diameter 52-ft. long valve chamber, an 11-ft. horseshoe shaped 34-ft. long grout chamber, and an 11-ft. horseshoe shaped 1,220-ft. long upstream tunnel.

As the downstream tunnel gets deeper the excavation profile changes in steps to account for thicker reinforced concrete required to withstand the increasing pressures of the future dam embankment and reservoir water levels; resulting in 417-ft. of horseshoe shaped downstream tunnel with varying thicknesses of concrete ranging from 24-in. to 30-in. thick, and 250-ft. of circular downstream tunnel profile with 18-in. thick concrete before reaching the valve chamber with 24-in. thick circular concrete. Currently, the tunnel sits 80-ft. beneath existing bedrock at its deepest point. When the dam embankment is complete in 2025, the valve chamber and grout chamber will be 350-ft. beneath the crest of the dam.

The valve chamber is a larger 30-ft. diameter waterproofed and concrete lined excavation at the centerline of the main dam which will house a 6-ft. diameter butterfly valve, HPU, and counterweight system. This valve will control water flow in and out of the reservoir, and the chamber is sized large enough for personnel to access the valve chamber from the downstream tunnel. The grout chamber is where the I/O tunnel crosses through Chimney Hollow's main dam foundation grout curtain. Remedial grouting of the curtain from within the tunnel will be required when this chamber is excavated to maintain the integrity of the dam's grout curtain. The upstream tunnel and grout chamber are sized just large enough to install the 6-ft. diameter steel pipe safely and backfill the annulus with concrete.

The I/O Tunnel is lithology is in Colorado's Fountain Formation. This is comprised of interbedded layers of sandstone, siltstone and shale. Rock UCS strength widely ranges from 2,000psi to over 20,000psi with layer thicknesses ranging from 6-in up to 20-ft. Groundwater inflows into the tunnel have been minimal.

To date, the downstream tunnel and valve chamber excavations are complete and ground supported with resin threadbar anchor bolts, welded wire fabric, and shotcrete. These tunnel features were excavated using traditional drill and blast methods, followed by rockwheel scaling and grinding to achieve lines and grades, and followed by ground support installation. Probe drilling is required in advance of tunnel excavation. To date no pre- or post-excavation grouting has been required with the minimal water inflows.

Barnard is currently completing structural consolidation grouting in the valve chamber to increase rock mass stiffness. We are also placing dental shotcrete in the downstream tunnel achieve lines and grades in advance of reinforced concrete placements.

Tunnel Designer: Stantec Consulting Services, Inc.; Construction Manager: Black & Veatch Corporation

Personnel: Northern Colorado Water Conservancy: Joe Donnelly, Project Manager; Stantec: Nadav Bar-Yaakov, Geotechnical Engineer; Greg Raines, Tunnel Practice Lead; Black & Veatch: Abir Kar, Inspector; Josh Meininger, Inspector; Barnard: Peter Turlington, Project Manager; Tony Galvez, Superintendent; Tom McDowell, Superintendent; Kyle Knaeble, Project Engineer; Tyler Larsen, Project Engineer; Sam Barnes, Project Engineer.

North East Boundary Tunnel (NEBT) Salini Impregilo Healy JV (SIH JV)

The $579.9 million Design & Build project for DC Water involves the design and construction of Division J of the DC Clean Rivers Project called North East Boundary Tunnel (NEBT). The project includes the construction of 26,700 ft of tunnel with 23 ft ID from 60 to 140 ft below grade. The tunnel is excavated using an Herrenknecht EPB TBM (Earth Pressure Balance Tunnel Boring Machine). The first section of the NEBT is excavated in a clay soil and the second part of the tunnel is in a sandy layer. Mix face conditions were expected for most of the tunnel alignment.

The project also includes the construction of 7 shafts, ranging from 20 feet to 55 ft diameter, and supported by unreinforced slurry walls or secant piles and lined using Cast in Place concrete. There are also 6 adits to be excavated using the Sequential Excavation Method (SEM) in ground previously improved through either jet grouting or ground freezing techniques. Finally, a 700 ft length of Diversion Sewer with 10 ft of internal finished diameter will be constructed using an EPB TBM in clay soil which will be lined with HOBAS pipes installed using the pipe jacking tunneling method.

As of December 2022, 95% of the works were completed. The tunnel excavation was completed in April 2021, the TBM disassembly in June 2021. The tunnel cleanup operations have been completed and the tunnel segment final reparation works are ongoing. The excavation of all seven drop shafts is already completed as well as the final concrete Cast In Place (CIP) liner. The construction of the hydraulic structures inside the shaft are completed for the 90% of the project drop shafts. All the Adits have been constructed and only one connection between Adit and NEBT is left. Regarding the diversion facilities to be constructed on the surface (Near Surface Structures), all the support of excavation system and the ground improvement have been fully completed while the excavation and the permanent structures construction have been completed in most of the construction sites. The 10-ft diameter TBM arrived on site last June 2021 and started the excavation of the 700-ft Diversion Sewer in August 2021. The drive was completed at the end of October 2021 and a total of thirty-eight (38) HOBAS pipes 20 ft long have been used to construct this tunnel. The NEBT is expected to enter in service by June 2023, while the rest of decommissioning and surface restoration works are planned to be completed by November 2023.

Special/unique Features of the Job: Unique aspects of the project include: Ground improvement using freezing technique to allow adit excavation in a very dense urban area of Washington, D.C.; Ground improvement under existing utilities using Jet Grout Elliptical columns; Hybrid ground improvement system using freezing and jet grouting method to allow the Adit construction in one of the construction site; Final TBM breakthrough into shaft filled with water; and Unreinforced slurry walls used as support of excavation for the drop shaft construction.

Designer: Brierley Associates; Major Subcontractors: Treviicos, Corman Kokosing, Keller-North America, EnTech Engineering; TBM Manufacturer: Herrenknecht.

Personnel: Owner – DC Water Clean Rivers Project: Carlton Ray (Vice President), Jeff Peterson (Construction Manager); Designer – Brierley Associates: Jeremiah Jezersky (Design Manager); Contractor – Salini Impregilo Healy Joint Venture (SIH JV): Daniele Nebbia (Vice President of Tunneling Operations); Fabio Ciciotti (Project Director); Andrea Sesenna (Project Manager); Flaviano Solesin (Tunnel Construction Manager); Gianluca Pianezze (Sites Construction Manager); Pietro Banov (Design-Build Coordinator).

Univar Solutions Sink Hole Turn – Key Tunneling, Inc.

Turn – Key Tunneling, Inc. (TKT) was contacted by Site Engineering, Inc. due to a sinkhole forming next to Univar Solutions Doraville Distribution Center. Upon investigation, it was determined that the sink hole was the result of a failing existing 42-in. diameter sanitary sewer pipe that ran along the property line. After consulting with TKT, Site Engineering, Inc. decided the best course of action would be for TKT to install a 20-ft diameter liner plate access shaft for temporary shoring so Site Engineering, Inc. could install a new manhole and reline the existing pipe with a cured–in-place pipe liner. This work would address the immediate sink hole issue and ensure that future failure of the sanitary sewer would not occur.

TKT installed this 20-ft diameter liner plate approximately 25 ft deep. Once Site Engineering, Inc. completed the pipe rehabilitation and installed the doghouse manhole base, TKT then removed the vertical shaft while stacking the manhole risers and backfilling the area around the manhole with Controlled Density Fill (CDF).Overhead power lines, along with an unknown 4-in. line that was encountered while digging the shaft, added some obstacles that provided challenges; but nothing that TKT could not handle as they were able to complete this emergency project on time and within budget.

The project, with a cost of $280,900, was completed between Sept. 13, 2022, and Dec. 30, 2022.

Personnel – Carter Hewitt, PM – Site Engineering, Inc.; Chris Leonard, PM – Turn – Key Tunneling, Inc.

McCook Reservoir, Des Plaines Inflow Tunnel Walsh Construction Company II, LLC

The $107.7 million McCook Reservoir, Des Plaines Inflow Tunnel project for the Water Reclamation District of Greater Chicago (MWRDGC) consists of approximately 5,850 lf of tunnel, 20-ft concrete lined finished diameter, with an approximate tunnel depth of 280 ft; one 12-ft diameter construction shaft, one 45-ft diameter gate shaft. The tunnel was excavated all through bedrock with the use of a drill-and-blast.

The project is approximately 98% complete. Major milestones completed was excavation of construction & gate shaft, excavation and lining of 20-ft diameter tunnel, and connection to Stage 1 of the McCook Reservoir with subsequent tunnel plug when the reservoir became live in 2017. In addition, the two 22 ft by 21 ft steel gates and hydraulic cylinders to control water within the tunnel when it becomes live have been delivered to the site and are currently installed. Gates are now operational and the Contractor has made the connection into the existing live 33-ft tunnel on the North end as well as to the reservoir on the downstream end. The tunnel is currently live and fully operational however miscellaneous project closeout punch list items remain open before final completion is approved. Final completion is anticipated for March 2023.

Special/unique features of the job include the time constraint of having the south end of the tunnel connected to Stage 1 of the reservoir before the reservoir came on-line at the end of 2017. The other unique feature was connecting the north end of the proposed tunnel to an existing live 33-foot tunnel that collects combined sewage for the Chicagoland area.

Tunnel & Gate Designer was Black and Veatch Corporation, Walsh Construction Manager is Mark Fournier, MWRDGC Project Manager is Kevin Fitzpatrick, Mining Company in charge for excavation of Stage 1 of the McCook Reservoir was Vulcan Materials (Vulcan & Walsh needed to coordinate their work when the proposed tunnel was connecting into the reservoir), Major subcontractors were Linita Design & Manufacturing Group, Pagoda & Electric Construction Inc., Truck King Hauling, Terrell Materials Corporation, Atlantic Painting Company and Steppo Supply & Construction Inc.

Personnel: MWRDGC: Kevin Fitzpatrick (Design Project Manager), Patrick Jensen (Design Engineer), Carmen Scalise (Construction Project Manager), Tim Nolan (Resident Engineer). Black and Veatch: Faruk Oksuz (Project Director), Cary Hirner (Project Manager) and Mark White (Engineering Manager). Walsh: Mark Fournier (Project Manager), Erik Schneider (Technical Engineer).

Three Rivers Protection and Overflow Reduction Tunnel Project (3RPORT) Salini Impregilo Lane JV

The $188 million Design-Bid-Build project for Fort Wayne City Utilities consists of approximately 24,500 lf of tunnel, 200 to 240 ft deep, excavated by a Herrenknecht slurry TBM, segmentally lined with a 16-ft finished inside diameter. There are three large diameter shafts, ranging from 29 to 69 ft diameter supported through the overburden with a slurry wall, with drill-and-blast excavation through rock. There are 13 small diameter drop and vent shafts, ranging from 2 to 8 ft, excavated by blind-bore drilling, and lined with ductile iron and centrifugally cast fiberglass reinforced polymer mortar pipe. Approximately 720 lf of adits will be driven using drill-and-blast method to connect the TBM tunnel to the drop and vent shafts. The TBM tunnel and adits will be excavated primarily through limestone of the Wabash Formation with anticipated high groundwater inflow in the range of 5,000 gpm to 10,000 gpm at 6.5 bar pressure.

Through the end of December 2022, the Project is 94% complete. TBM excavation is completed, the shields of the machine have been buried, and the trailing gear has been removed. The underground adit and deaeration chambers have received pre-excavation grouting and drill-and-blast excavation activities are completed. An FRP lining and cast-in-place connection to the main tunnel was completed for all the adits. The Pump Station, Working, and Retrieval Shafts have received cast-in-place concrete liners. Cleaning of the tunnel is underway and remains the only activity for completion of the Project. The estimated completion date is May 4, 2023.

Tunnel Designer: Black & Veatch; Construction Manager: Jacobs; Major Subcontractors: CSI Tunnel Systems, Keller – North America, Hardman Construction, Bunn Inc., F.A. Wilhelm Construction, Service Electric. TBM Manufacturer: Herrenknecht.

Personnel: Owner / City of Fort Wayne: Mike Kiester (Manager, City Utilities Engineering); Tunnel Designer / Black & Veatch: Leo Gentile (Senior Project Manager), Matthew Pierce (Project Manager); Construction Manager / Jacobs: Todd Webster (Construction Contract Manager); Contractor / Salini Impregilo Lane JV: Daniele Nebbia (Vice President of Tunneling Operations), Carlos Lang (Project Director), Lance Waddell (Project Manager).

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 and chamber build out is ongoing. All drop and vent shaft excavation is complete, and shaft lining is approximately 95% complete. Tunnel concrete lining operations and the retrieval shaft concrete lining is 100% complete. Based on the terms of a federal consent decree, the Fall Creek Tunnel must be operational by the end of 2025.

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.

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 in November 2021 the TBM mined through the 30-foot diameter intermediate shaft approximately 20,000 feet into the alignment. TBM mining was completed in August 2022. Drop shaft, vent shaft, and adit construction is ongoing. Tunnel concrete lining operations are anticipated to commence in March 2022. This milestone marks the end of TBM mining for Citizens’ DigIndy program.

The entire 28-mile DigIndy system will have utilized a single Robbins main beam TBM. In addition to 28 miles of hard rock mining, the TBM will have been backed up over nine miles allowing the elimination of multiple launch and retrieval shafts. 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.

Ohio River Tunnel Shea-Traylor JV (S-T JV)

The $161 million Ohio River Tunnel for the Louisville and Jefferson County Metropolitan Sewer District (MSD) was given notice to proceed (NTP) on November 8, 2017. The project consists of a 21,300 ft long tunnel with a 22 ft excavated diameter and 20 ft finished diameter. The tunnel is 200 ft deep with six drop shafts and two larger 40 ft finished diameter shafts for the TBM Working Shaft and Tunnel Pump Station Shaft. Ground conditions include limestone and dolomite rock with interbedded shale formations, potential fault zones, and natural gas zones in the rock. Tunnel excavation was completed using an open face, main beam Robbins’ tunnel boring machine (TBM).

TBM excavation commenced January 2019 with a hole-through date of September 22, 2020. Tunnel excavation included backing up the entire TBM assembly through 1,100 ft of a tunnel bifurcation section, before continuing to excavate the main tunnel alignment. This TBM backup was necessary since drill and blast excavation was not permitted below Kentucky Transportation Cabinet (KYTC) highway infrastructure. Natural gas was encountered only once during tunnel excavation. No groundwater inflow nor any fault zones were encountered during tunnel excavation. Certain sections of excavated rock deteriorated faster than expected, causing some delay during tunnel excavation and concrete lining. Most of the tunnel concrete lining was completed February 2022, with minor sections near the Working Shaft and Retrieval Shaft being lined in the subsequent month. The final pre-cast concrete shaft cover sections for the Working Shaft were set in place on May 16, 2022.

The Ohio River Tunnel project achieved Substantial Completion (SC) on May 27, 2022; and Final Completion on August 01, 2022. The tunnel system has been in service since its SC date and is successfully functioning as designed. Combined Sewer Overflows are being captured by the tunnel system and it is well on its way to helping Louisville MSD achieve safe, clean waterways.

The next phase on the ORT Project is tunnel inspection, after the whole system went into operation. Louisville MSD plans to inspect the tunnel around the second quarter of 2023, which is within the 12-month warranty period. Along with Black & Veatch, Louisville MSD is evaluating various options for tunnel inspection, including a remotely operated vehicle using sonar technology, which will navigate like a submarine within the filled ORT tunnel.

Tunnel Designer: Black & Veatch; Construction Manager: Black & Veatch; Major Subcontractors: Platt Construction, Steppo Supply, T.E.M., CTL Engineering, Harmon Steel, MAC Construction. TBM Manufacturer: Robbins.

Personnel: Greg Powell: MSD Construction Manager; Jacob Mathis: MSD Project Manager; Jonathan Steflik: Black & Veatch Design Project Manager; Mark Bradford: Black & Veatch Design Tunnel Lead; Pete Boysen: Black & Veatch Sr. Construction Manager; Alston Noronha: Black & Veatch Tunnel Design Engineer and Construction Manager; Shemek Oginski: S-T JV Project Manager; Jesse Salai: S-T JV Operations Manager.

Jefferson Barracks Tunnel SAK Construction LLC

The project includes approximately 17,800 lineal feet of TBM bored tunnel, and installation of a 7-ft diameter fiberglass reinforced polymer mortar carrier pipe and fiber optic conduits in the tunnel.The tunnel is located adjacent to the Mississippi River, extending southwardly from the Lemay Wastewater Treatment Plant, and is intended to replace an aging system of pump stations, force mains and shallow sewers that convey wastewater to the treatment plant. The tunnel is excavated through limestone bedrock at depths ranging from 140 to 215 ft below the ground surface.

Construction was by a main beam TBM launched from an 88-ft diameter shaft which will serve as a pump station to be constructed under a separate contract. A pre-excavation grouting program was conducted at the launch shaft to minimize inflow from any karstic features that could have been encountered during shaft excavation. The TBM will be removed via a finished 18-ft diameter, concrete lined shaft at the upstream terminus of the tunnel. Fourteen bored shafts for drop pipes, vent pipes, and fiber optic conduits were also drilled along the tunnel alignment from the surface to the tunnel depth and passed through karstic zones above the tunnel alignment.

The project is about 85 percent complete with excavation of the tunnel using a 13.5-foot diameter TBM being completed on December 20, 2022. Once the TBM is broken down and removed, the tunnel will be prepared for pipe installation and the chamber connections to the tunnel for the remaining drops excavated and constructed. Carrier pipe installation should start in March 2022 followed by placement of cellular grout backfill for the carrier pipe. Construction of the last two intake structures along the tunnel alignment is also in progress and should be completed in early spring 2022. Final Completion is expected in April 2024.

Karst was identified as the most important geotechnical issue for the project as the bluffs along the Mississippi River are riddled with caves and karstic crevices with sinkholes in the upland areas adjacent to the bluffs. The presence of karst influenced the vertical alignment of the tunnel and impacted the design and construction of shafts that passed through the karstic zone.

Two locations of karst were encountered within the tunnel during TBM excavation. The first location was encountered with an 11-foot diameter TBM from about Station 71+20 to 71+95. The second location was encountered with the 13.5-foot diameter TBM from about Station 92+65 to 93+67.

Tunnel Designer: Jacobs Engineering Group; Construction Manager: Shannon & Wilson; Major Construction Subcontractors: Case Foundation (shafts), ACT (pre-excavation grouting), Williams Tunneling (tunnel construction and carrier pipe installation), Goodwin Brothers Construction (intake construction). TBM Refurbishment: Robbins.

Personnel: Patricia Pride, Project Manager, Metropolitan St. Louis Sewer District; Kent Kotthoff, CM Program Manager, Metropolitan St. Louis Sewer District; Ray Scherrer, Division Inspector, Metropolitan St. Louis Sewer District. William Haag, Design Project Manager, Jacobs Engineering Group; Andrew Bursey, Lead Tunnel Designer, Jacobs Engineering Group; Tom Abkemeier, CM Project Manager, Shannon & Wilson, Inc.; David Donovan, Resident Project Representative, Shannon & Wilson, Inc. Dan Swidrak, Project Manager, SAK Construction; Terry Beesley, General Project Supt.; Jack Bragg, Project Superintendent, SAK Construction; Jack Lynch, Tunnel Division Safety Manager, SAK Construction; Zach Meyer, Safety Manager, SAK Construction.

Lower Meramec Tunnel (11746) SAK Construction LLC

This is a $174 million project for the Metropolitan St. Louis Sewer District (MSD) comprising 35,903 ft (6.8 miles) of 11-ft excavated diameter, 8-ft inside diameter, 78 to 286 ft deep sanitary sewer tunnel which is expected to be mined utilizing a TBM entirely within limestone, shale and dolomite rock with two required construction shafts and six drop structures. The project is approximately 15% complete.

The Contractor has completed drilling the drop and vent shafts, installed secant piles at the termination TBM retrieval shaft and completed excavation of the termination shaft, tail tunnel, starter tunnel, and the adit to the Fenton dropshaft. The Contractor has completed installation of the upper portion of the concrete lining at the starter shaft.

This project is an extension of the previously constructed Baumgartner Tunnel Project which was 20,200 ft long with an excavated 12.5-ft diameter. Bedrock conditions anticipated to be encountered consist of the Warsaw Formation and the Burlington-Keokuk Limestone. The Warsaw Formation is composed primarily of limestone and shale with small amounts of chert whereas the Burlington-Keokuk Limestone includes limestone and abrasive chert which, in places, composes up to 40% to 60% of the rock mass.

Tunnel Designer is WSP as a subconsultant to HDR Engineering, Inc. The Construction Manager for the project is Black & Veatch.

Key Project Personnel: Metropolitan St. Louis Sewer District – Design Project Manager: Jerry Jung; Construction Project Manager: Ray Scherrer. Tunnel Design Engineer: Everett Litton, WSP. Construction Manager: John Deeken, Black & Veatch. SAK – Project Manager; Brent Duncan. Project Engineer; Spencer Miller. Tunnel Division Safety Manager; Jack Lynch. Safety Manager; Cedric Bransford. General Project Supt.; Terry Beesley. Project Superintendent; Steffan Peck.

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

Southland/Mole JV is completing this $206 million project for the City of Dallas. The job comprises 26,385 lf of tunnel (32 ft, 6 in. excavated diameter; 30 ft finished diameter); 8 Intake Shafts (ranging from 120 to 200 vf depth); and 6 lateral tunnels excavated by roadheader or excavators/breakers. The tunnel is being constructed primarily through Austin Chalk with a Main Beam TBM.

Crews completed excavation of the eight shafts (5 Intake Shafts, 1 Outfall Shaft, 1 Dewatering Station Shaft, and 1 Access Shaft) ranging from 22 to 35 ft diameter, and have also completed excavation of the six lateral tunnels, with the final lateral tunnel near completion. The lateral tunnels range in diameter from 12.5 to 25 ft in diameter and 50 to 500 ft in length.

A milestone was reached in July 2022 with the completion of TBM mining. The main underwent a diameter change mid-bore, complete 10,000 lf at 37 ft, 7 in. and 16,000 lf at 32 ft, 6 in. Crews are currently demobilizing the TBM from tunnel and mobilizing equipment for cast-in-place tunnel concrete lining operation. CIP lining is ongoing at multiple lateral and shaft locations. The estimated completion date is August 2025.

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

Surface Water Supply Project – Segment B3: Long Tunnel Jay Dee/HB Trenchless JV (JDHB JV)

Jay Dee Contractors, Inc. was awarded Segment B3 of the Surface Water Supply Project by the West Harris County Regional Water Authority. Jay Dee Contractors, Inc. has entered a joint venture with HB Trenchless as JDHB JV. The $112.7 million project was issued NTP on May 24, 2022, and has an estimated date of completion is April 2025. The owners are West Harris County Regional Water Authority and North Fort Bend Water Authority.

Segment B3 consists of approximately 23,000 lf of 96-in. diameter waterline with all necessary valves and appurtenances, along the ExxonMobil Strip Fee/Corridor and Sinclair Pipeline Corridor from west of I-45 to the south side of Hopper Rd. The proposed water line installation will be primarily installed with tunneling construction. There are 5 main shaft areas and 2 CAV-Access w/Extra Depth Manhole Sites. The tunnel will cross Harris County roads, TxDOT roads, Union Pacific Railroad (UPRR), Harris County Flood Control District (HCFCD) drainage systems, and private pipelines. Additionally, the work requires installation of air valves, butterfly valve, pre-cast concrete manholes, and cathodic protection facilities, and removal and replacement of existing fencing. This project is a part of the overall Surface Water Supply Project.

The tunnel will be mined with a 126-in. TBM and the primary liner will be ribs and lagging. The tunnel is roughly 40 ft deep. There are seven shafts along the alignment. Anticipated ground conditions are mostly fat and lean clay in the excavation face, with pockets of sandy material above the tunnel in the last quarter of the drive. The conditions appear adequate for open mode excavation.

The TBM is launched and excavating between the shaft at Hopper Rd. and the shaft on Aldine Westfield. The second shaft is fully excavated, and the other sites are being prepped for shaft excavation. The entire tunnel alignment is being installed on Pipeline Easements, under existing live oil and gas pipelines.

Other Major Parties Affiliated with the Project: DE Corp. (DEC), Black and Veatch, Jennmar, Olsen and Guerra, Geocomp.

Personnel: Construction Team and Office – Project Manager: Nate Long; Senior Project Manager: Tim McQueary; Project Engineer: Will Hodder; General Superintendent: Martin Valles; Senior Construction Engineer: Sean McDonald; Jay Dee Contractors, Inc. President: Mike DiPonio; HB Trenchless CEO: Jon Harper. Program Managers – Program Manager: Wayne G. Ahrens, P.E.; Deputy Program Manager: Melinda Silva, P.E. WHCRWA Construction Management Team and Office – Program Construction Manager: Troy Anthony, P.E.; Construction Manager: Sergio Flores, P.E.; Program Construction Manager: Chase Juhl, P.E. North Fort Bend Water Authority Representatives – Senior Project Manager: Kyle Jones, P.E.; Senior Inspector: Thomas Bannan.

Cottonwood & Hackberry Creek Wastewater Interceptor Improvements Super Excavators, Inc.

Super Excavators, Inc. was recently awarded this $26.7 million project for the City of Irving. NTP was issued Jan. 3, 2023. Estimated completion date is July 2024.

The work generally consists of approximately 4,900 lf of 60- and 54-in. fiber reinforced pipe by microtunneling methods, associated manholes, one junction box, lift station demolition, Rochelle lift station site improvements, and odor control devices together with all associated appurtenances. The project site is in the City of Irving at Riverside Drive from Spur 348 to approximately 1,500 ft south of California Crossing Road. It is the first microtunnel project for the City of Irving.

Personnel: Project Manager: Mike Garbeth of Super Excavators, Inc.; Superintendent: Nate Wiedmeyer.

River Renew Tunnel System Project Contract No. 19-079 Traylor-Shea JV

The River Renew Tunnel System comprises 11,400 LF of 12-ft ID CSO Tunnel lined with a single-pass of bolted and gasketed precast concrete segments. Depth of the tunnel varies from 120 to 140 ft below surface. Three shafts: Launch Shaft (Pumping/Screening Shaft), Intermediate Shaft (Drop Outfall 002), and TBM Reception Shaft (Drop Shaft Outfall 001). Ground conditions at tunnel horizon: Predominately stiff clay with dips of saturated silty sands. Tunnel will be excavated using a 14.7-ft OD Earth-Pressure Balanced TBM manufactured by Herrenknecht AG.

The TBM was launched in short-mode on Nov. 1, 2022. As of Dec. 31, 2022, 275 lf of tunnel were completed. Excavation of Drop Shaft Outfall 002 was completed on Oct. 31, 2022. Excavation of Drop Shaft 001 began on Nov. 28, 2022 and is currently ongoing.

The $445 million design-build project is being completed for owner Alexandria Renew Enterprises. 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.

Personnel: Program Manager: Justin Carl; Resident Engineer: Ray Hashimee; Project Manager: Jean-Marc Wehrli; Construction Manager: Ron Heater; General Superintendent: William Crider; Design Manager: Samer Sadek.

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 69% complete (as of the end of December 2022). All five shafts are complete and both tunnel boring machines have launched. The 21.5-ft diameter TBM, ("Mudhoney"), has completed approximately 9,000 ft (65%) of the tunnel drive that begins at the Ballard neighborhood eastward along the north side of the Ship Canal toward the Wallingford neighborhood. The 10-ft diameter MTBM is scheduled to complete its journey from Fremont southward under the Ship Canal toward the Queen Anne neighborhood by February 2023. After this period crews will install conveyance pipe and below grade vaults.

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.

In mid January 2023 the machine reached the second safe haven location where the ground had been improved by jet grouting last year, and further cutting tool replacement and repair works are under way with access to the cutterhead under free air. The team is looking forward to improving upon current production achievements – 90 ft in one day, 367 ft in a week and 1,245 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: Gianluca Pianezze; Technical Manager: Basilio Giurgola.

Marshall University Horizontal Mine Shaft Turn – Key Tunneling, Inc.

Preliminary design for a subterranean testing facility included a double 7 ft x 7 ft tunnel converging to an underground 25 ft x 25 ft observation room where students could safely perform testing. The original bids were well above the engineer's estimate so a redesign was presented that included a 160-lf, 72-in. tunnel that led to a reduced size (8 ft x 8 ft) observation room along with an emergency access provided by a 236-lf run of 36-in. tunnel from an alternative angle. This would require an underground intersect of the two tunnels approximately 40 ft below grade.

Turn – Key Tunneling, Inc (TKT) was contracted by Marshall University (MU) to perform the specialized trenchless construction. To date the 160-lf, 72-in. tunnel has been completed. The 72-in. tunnel had complications as the geotechnical report showed the competent rock several feet higher than what was encountered on the site. To offset this, the tunnel drive was lowered and a Spirolite liner has been offered as a final liner for first 80 lf where the rock integrity is questionable.

The 36-in. tunnel is being excavated with a 42-in. Robbins Small Boring Unit (SBU) and is nearing breakout into the observation room. Once this drive is completed, the SBU will be retracted back though the tunnel and a 36-in. HDPE pipe will be installed as the final liner and grouted in. The observation room excavation will follow and ancillary work to dress up the site will be completed and restored.

The $1.8 million project began Oct. 1, 2022, and is scheduled to complete around April 1, 2023.

Turn – Key Personnel – Chris Leonard, Proj. Manager; Gary Ison – Superintendent; Josh Followay, Foreman.

Stage 2 LRT Project – O-Train East and West Extension Project East-West Connectors (EWC)

The Stage 2 Confederation Line east and west extensions 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 west extension includes two cut-and-cover tunnels:-The 3-km Parkway Tunnel will travel between Dominion Station and Lincoln Fields Station traveling underneath the Sir John A. Macdonald Parkway, Richmond Road, and Byron Linear Park.-The 270-m Connaught Tunnel will link 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 November 2022 it was 43% complete. -Construction of the Connaught Tunnel began in 2021, and at the end of November 2022 it was 52% complete.

The tunnels are expected to be fully completed at the end of 2024. The O-Train West extension is expected to begin revenue service at the end of 2026.

The Parkway tunnel will travel through federal lands and a City of Ottawa linear park in order 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.

Overall, the Stage 2 LRT O-Train East and West extensions are a signature project in Canada's national capital, funded by three levels of government. Therefore, there is a strong focus to ensure that the project is delivered with minimal impact on the community. This requires very close, on-going collaboration with all stakeholders and the public, as building a large infrastructure project in an urban environment can be disruptive.

And, 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 metres of concrete every 7-10 days. The team is also using two Peri Travelling Formwork systems, which essentially perform the same functions but in less uniform spaces.

Design engineering services are being provided by WSP Canada and Hatch Ltd.

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

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

Currently, it is anticipated that the $1.6 billion (CAN) O-Train South extension will be ready for turnover to the operator in Q3 2023.

The tunnel is located under Dow's Lake and was originally opened in 1967. As part of the Stage 2 project it is being rehabilitated.

The length of the tunnel is 578 m with 23 reinforced concrete box segments separated by 22 expansionjoints. 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.

As of January 2023, the physical works in the tunnel are at approximately 58% completion. This number is expected to reach 100% by Q3, after which works in the tunnel will shift to the testing and commissioning of the new passenger rail system.

Work is currently underway to upgrade the drainage system and modernize the tunnel ventilation system, standpipe system, communication systems, and emergency walkway to align with National Fire Protection Association (NFPA) -130 standards.

Work that has been complete so far is the repairs of expansion joints and cracks areas that evidenced water infiltration in the tunnel by sealing the expansion joints and injecting existing cracks. The tunnel standpipe system has been upgraded and is ready for testing.

During Q4 of 2022, concrete ties and brand-new rail were installed in the tunnel, replacing the old timber ties. This marked the culmination of a significant revamp of the track infrastructure in the tunnel. The track bed (composed of subgrade soil, granular fill, ballast mat, and ballast) was refurbished with new materials and checked every step of the way with conformance to current track design standards. This has allowed the tunnel to be used for rail-mounted vehicles to pass through and access areas on either portal for snow removal and construction.

Some of the remaining works include cable pulling for communication systems, testing and commissioning of communications systems, train testing within the tunnel, emergency scenario testing, ventilation system testing installation of emergency stairs, and reinstallation of the walkways.

Fiber optic cable will be installed early in 2023 to provide cellular service in the tunnel. The cable is a 1.25-in. radiating cable, optimized for 4G cellular technology and capable of providing 5G service.

There are some interesting safety features about the tunnel. There are three safety bays, which are rooms with doors that are designed for people to enter in case of an emergency in the tunnel. 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.

Ashbridges Bay Treatment Plant Outfall Southland | Astaldi Joint Venture

The $300 million Ashbridges Bay Treatment Plant Outfall for the City of Toronto comprises 3.5 km if 8-m diameter TBM excavated tunnel lined with 7-m ID precast concrete segmental lining, and one 16-m diameter shaft, 85 m deep. It also includes construction of 50 1-m diameter risers in Lake Ontario. The alignment for the tunneling is mostly Georgian Bay shale.

To date, the project is 80 precent complete, with final completion expected by fall 2024. Shaft excavation is complete for tunnel activities, and the 8-m diameter segmental tunnel is complete. The TBM has been demobilized. The offshore risers installations are complete, and riser connections in the tunnel are 70% complete. The construction of the Effluent Conduit Structure is underway. Completion in fall 2024.

Consultant & Designer: Hatch with Jacob & Baird; 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 (Francisco Urrutia); General Superintendent (Curtis Bahten); Underground Superintendent (Jeff Reagan).