2021 North American Microtunneling Review – Microtunneling Job Log

Below is a look at some of the recently completed and ongoing microtunneling projects across North America from the 2021 North American Microtunneling Industry Review.

The need for improved infrastructure across North America is strong, and getting stronger as existing utility systems age. Public demand for minimally invasive construction techniques is high, while more and more public discussion revolves around the topic of infrastructure investment. At some point, funding needs to be committed to rebuilding our infrastructure, and microtunneling is well-positioned to complete the work, particularly in tight urban areas.

To submit your project to the Microtunneling Job Log, email Jim Rush, editor Trenchless Technology, at jrush@benjaminmedia.com.

UNITED STATES

CALIFORNIA

Los Angeles

City Trunk Line South Unit 3

W.A. Rasic Construction

The project comprises 5,357 lf of pipe replacement in total, using a combination of open-cut construction and microtunneling to install 60-in. diameter welded steel pipeline. The project was awarded to W.A. Rasic Construction (Rasic) with a low bid of $43 million. Notice to Proceed was issued in August 2019. Expected completion date is September 2022.

The tunneling portion of the CTLS 3 project comprises five microtunnel drives and three launch pits. Two of the launch pits will be used to launch tunnels from either side. To perform the tunneling operations, Rasic selected an Akkerman SL SL82P MTBM, which was pre-approved by LADWP and recommended by previous tunneling subcontractors.

The five microtunnel drives total approximately 4,200 lf with each drive approximately 900 ft long. Depths are above the water table approximately 35 ft deep through clay and sandy conditions. Crews are installing 20-ft sections of 72-in. diameter Permalok steel casing pipe into which the 60-in. CML&C welded steel pipe will be finalized.

The owner is the Los Angeles Department of Water and Power.

Los Angeles

River Supply Conduit Improvement

Upper Reach – Unit 7

Frontier-Kemper

The project comprises approximately 2.5 miles of 78-in. welded steel pipeline, and is being constructed by Frontier-Kemper. In addition to the 11,755 ft main line tunnel, Frontier-Kemper’s contract includes a microtunneled connection as well as a 900-ft open-cut connection.

Frontier-Kemper Constructors Inc. was awarded the $121 million RSC 7 contract in 2018. The first section of work to be completed was a 500-ft microtunnel that traversed under the Los Angeles River from Forest Lawn Drive, adjacent to the famous Forest Lawn Cemetery, to the main TBM launch shaft and primary staging area for the project in Johnny Carson Park. The microtunneling machine was launched from a 60-ft deep, 30-ft diameter liner plate shaft completed in September 2019.

Crews used an 82-in. Akkerman MTBM, upsized to 104 in., and a mixed face cutting cuttinghead that included disc cutters and drag bits to combat the abrasive geology. The MTBM had an accessible face with rear-loading cutters, which allowed face access if needed.

The alignment started in the Topanga formation but quickly transitioned to the cobbly alluvium under the Los Angeles River. Crews experienced heavy wear on the slurry system while dealing with the difficult ground conditions, but managed to complete the drive in March 2020.

Frontier-Kemper used 102-in. ID Permalok casing pipe from Northwest Pipe, which was lined with the 78-in. welded steel final liner, also from Northwest Pipe. The welded steel pipe was epoxy coated on the outside and cement mortar lined on the inside. Following installation of the final liner, the annulus was filled with 2,000 psi backfill.

Main line tunneling is expected the be complete by the end of the year. The overall River Supply Conduit Improvement Upper Reach – Unit 7 project is anticipated to be complete in mid-2022. The owner is the Los Angeles Department of Water and Power.

Marina Del Rey

Venice Dual Force Main and Venice Pumping Plant Generator Replacement Project

Vadnais Trenchless Services Inc.

This $88.8 million project for the City of Los Angeles Department of Public Works involves the construction of a new 54-in. ID force main sewer extending approximately 10,392 lf, which originates from a newly constructed manifold adjacent to the existing Venice Pumping Plant. From the manifold the alignment will proceed east, then southeast, and cross beneath the Marina Del Rey Harbor inlet and Ballona Creek channel, continue traveling south under Pacific Avenue and Vista Del Mar ending at the Coastal Interceptor/North Outfall Sewer (CIS/NOS) Junction structure.

The majority (~9,450 lf) of the new 54-in. line will be constructed using microtunneling. Most of the microtunneling will be direct-jacked RCCP and approximately 2,800 lf of 80-in. Permalok Casing with RCCP Carrier will also be installed. The cut-and-cover construction method will be used for the remaining 150 lf.

The project also consists of the demolition of existing equipment, procurement and installation of three new generators along with ancillary controller, transfer switches, plus exhaust and cooling systems at the Venice Pumping Plant. Two new 750 kW (480 V) generators, and one new 1,500 kW (480 V) generator with complete emissions control systems and fluid storage will be furnished and installed.

This project is unique with the entire alignment alongside the ocean, making water and natural gasses a big challenge to deal with. The large scope of work and frequent changing underground conditions along with several different shaft construction techniques make this an extremely challenging project.

Award on the project was made in February 2017 and physical work began in May 2017. The project is scheduled to be complete by the Spring of 2022. The project was 92 percent complete at the end of August 2021. The City of Los Angeles Engineering furnished the design. Crews are using MTS 1500, MTS 1650 and MTS 1850 MTBMs for tunneling.

Millbrae

Pacific Gas & Electric Company R-985 L-101

Channel Crossing

Vadnais Trenchless Services Inc.This $460,000 project for Pacific Gas & Electric Company consisted of installing 140 lf of 24-in. OD Sacrificial Steel Casing via microtunnel on one single drive. The microtunnel was installed using an Iseki TCC500 beneath the existing concrete lined channel and storm drain/sanitary sewer utilities, providing a minimum depth of cover of approximately 18 ft below the channel bottom, and 10 ft of vertical separation from an existing 33-in. RCP storm drain installed beneath the channel.

Shafts for microtunneling were between 32 and 35 ft deep. Microtunneling was performed primarily through a composition of favorable soil conditions, consisting of silty sand and clayey sand 25 to 30 ft below beneath the groundwater table. VTS utilized the sacrificial case-and-displace method with steel casing pipe to install the 24-in. steel gas pipe. ARB as the contractor supplied, welded, coated and tested the 24-in. gas pipeline product pipe installed by VTS. When completed, VTS recovered the MTBM and casing used to push the 24-in. gas line into its final position, resulting in a final installation of 24-in. gas pipeline with no casing.

VTS mobilized in June 2021 and completed all work in July 2021.

Morgan Hill

Anderson Dam Tunnel Project

Vadnais Trenchless Services Inc.

This $8.8 million project for Santa Clara Valley Water consists of a single microtunneling drive with the installation of 372 lf of 96-in. diameter steel casing pipe. The MTS 2350 MTBM will be launched from a chamber tunneled under the Anderson Dam and recovered in the Anderson Reservoir. The tunnel drive will be a mixture of soft and hard materials.

The Anderson Dam Tunnel Project MBTM lake tap will be launched from inside of a 24-ft horseshoe tunnel mined under the Anderson Dam. The 1,600 lf conventional tunnel will incorporate steel horseshoes and a reinforced concrete lining. A reaction frame and portal launch seal will be used to tunnel from the chamber to a lake tap landing pad deep below the surface of the Anderson Reservoir. The MTBM will be recovered using specialty divers, barges and cranes.

Planned Mobilization for the MBTM lake tap is scheduled for November 2022 with a Completion Date of May 2023.

AECOM is the engineer. Flatiron West is the general contractor with Vadnais as tunneling subcontractor.

Morro Bay

Water Reclamation Facility Lift Station and

Offsite Pipelines

Vadnais Trenchless Services Inc.

This $1.2 million project for the City of Morro Bay consists of a single drive of 310 lf of 60-in. x 0.75-in. wall Trinity Press Fit Steel Casing. Microtunneling will be performed using an MTS 1500 through a composition of poorly graded clean sand, clayey sand, and lean clay (lean clay limited to west end).

The microtunnel is being installed under a roundabout intersection of Morro Bay Blvd. and Quintana Rd. Shafts for microtunneling are between 18.5 and 22 ft deep. The tunnel is installed 12 ft below the groundwater table. Microtunnel is being installed through non-cohesive flowing sands and numerous overlying critical utilities, critical surface improvements, and heavily traveled traffic near the roundabout.

VTS mobilization date was July 5, 2021, and the project was expected to be completed by mid-September 2021. Waterworks Engineers was the engineer and Anvil Builders Inc. was the general contractor, with Vadnais Trenchless Services as the tunneling subcontractor.

San Carlos

SVCW Belmont Gravity

Pipeline – Design Build

Vadnais Trenchless Services Inc.

This $9.8 million project for Silicon Valley Clean Water consists of seven microtunnel drives in which VTS will be supplying, microtunneling, and contact grouting approximately 4,324 lf of 36-in. Hobas FRP Jacking Pipe (in 20-ft lengths). Shafts for the microtunneling will be between 17 and 29 ft deep and consist of watertight, sheet pile construction. The microtunnels will be installed in soils consisting primarily of medium-stiff to stiff, fat to lean clay with sand. All tunnel alignments have been approximated to be below the groundwater table, however it is possible that groundwater conditions at the site could change due to variations in rainfall, groundwater withdrawal or recharge, daily tide cycles, surface runoff, etc.

This project consists of seven 36-in. microtunnel drives with different jacking and receiving pit locations. These tunnels will run parallel to the US101, with one tunnel that crosses the US101 northbound on/off ramp. Tunnels will also be installed west of the San Carlos Airport (SQL), which will require multiple FAA OE/AA 7460-1 Obstruction Filings/Permits, as well as continuous FAA/Airport Operation coordination. A FAA height restriction of will also be implemented in working zones near the airport.

VTS mobilized to the project on July 28, 2021, with an estimated completion date of Phase 1 (3 Reaches) by Dec. 1, 2021. Phase 2 (4 Reaches) is scheduled to commence in late-May 2022. J.F. Shea / Parsons, a Joint Venture, is the general contractor and designer. VTS will use an Iseki TCC800 MTBM.

Santa Cruz

Coast Pump Station Raw

Water Pipeline Replacement

Vadnais Trenchless Services Inc.

This $4.6 million project for the City of Santa Cruz consisted of a single drive of 221 lf of 42-in. x 5/8-in. wall Permalok steel casing. The microtunnel was installed using an Iseki TCS900 Super Mole under the San Lorenzo River from a 72-ft deep jacking shaft and into a 51-ft deep receiving shaft. The microtunnel progressed through three soil formations 15,000 psi Quartz Diorite, weathered Schist and finally flowing sandy gravel with cobbles. Encountered water head was 37 ft.

VTS mobilized in May 2020 and completed all work in February 2021. Kleinfelder was the engineer.

COLORADO

Aurora

Zone 3: 60-in. Gun Club Road Pipeline from E 6th Ave to I-70

BTrenchless Inc.

This $2 million project for Aurora Water comprises one drive of 460-lf of 72-in. diameter Permalok pipe, installed behind an Akkerman SL60 MTBM. Soils are primarily fine to coarse alluvium and ground water is present at 7 to 8 ft below the surface.

This is the second phase of a new 60-in. pipeline that connects to an existing 36-in. water main at E. 6th Ave. and proceeds north through city right-of-way east of Gun Club Rd., under I-70 via a 460-ft long tunnel to an existing 30-in. water main adjacent to Furniture Row. The pipeline is approximately 7,100 lf in total length. Phase II of the project will install the remaining 4,860 lf of pipeline and the trenchless crossing under I-70.

The project is anticipated to start in January 2022. Dewberry Engineers Inc. is the engineer, and BTrenchless Inc. is the tunneling subcontractor to Reynolds Construction LLC.

Denver

PAR 1232 Second Creek Interceptor

Bradshaw Construction Corp.

Bradshaw Construction Corp. is currently performing work on the PAR 1232 Second Creek Interceptor project in Denver. The wastewater interceptor will include eight trenchless crossings totaling over 4,100 lf, which Bradshaw will perform by microtunneling. Tunnel crossings will range from 48-in. to 73.5-in. steel casing, with drive lengths reaching 1,500 lf on the longest crossing. FRP from 30-in. to 60-in. will be installed and backfilled once tunneling operations are completed. The tunnels will be installed out of steel sheeted shafts, installed by Lawrence Construction Company. The project geology will consist of multiple mix face conditions with claystone overlaid by coarse and fine alluvium, underneath the water table. Tunnels will pass underneath roads, highways, UPRR and BNSF tracks. The project members include the Metro Wastewater Reclamation District (Owner), HDR Engineering Inc. (Engineer), Garney Construction (CMAR), and Bradshaw Construction Corp. working as tunneling subcontractor. Project Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

Fort Collins

Greeley Waterline Replacement

BTrenchless Inc.

This $1.4 million job for the Greeley Water and Sewer Department consists of one 380-lf drive using 51-in. diameter Permalok steel pipe using an Akkerman SL51 MTBM. Depths range from 10 ft to almost 20 ft in a sandy gravel material with ground water. The project crosses under Interstate 25, which is a very heavily used interstate that could not be shut down. Special precautions had to be made for monitoring to prevent heaving the interstate or possibly causing a void underneath the interstate. The project started in August of 2020 and was completed by October 2020. AECOM was the designer, and BTrenchless Inc. was the tunneling subcontractor to and Connel Resources.

Fort Lupton

Lupton Lakes Inlet/Outlet Facility

BTrenchless Inc.

The $1.92 million Lupton Lakes Inlet/Outlet Facility for Denver Water consists of one drive of 800 lf of 66-in. diameter (69.2-in. OD) Hobas pipe. Crews will use an Akkerman SL60 MTBM. Depths range from 10 ft to almost 40 ft in a sandy gravel material with ground water.

The project starts off in fill from an old gravel pit. At approximately 80 ft into the drive, there is a clay cutoff wall that was used to keep groundwater out of the gravel pit. After penetrating the clay cutoff wall, crews are tunneling through a sandy material with approximately 8 ft of ground water. The project has started, and crews are currently waiting on casing pipe with an expected deliver of Nov. 1, 2021.

AECOM is the engineer, and BTrenchless Inc. is the tunneling subcontractor to Moltz Construction Inc.

Westminster

Westminster Big Dry Creek

Interceptor System Improvements

BTrenchless Inc.

This is a $1.16 million project for the City of Westminster that includes a 444-lf of 51-in. OF Permalok T-5 casing pipe installed behind an Akkerman SL51 MTBM. Depths range from 15 to 25 ft below grade with ground water just above crown of pipe. Ground conditions were split face changing from a full-face of claystone to both coarse and fine alluvium. Solid wall 30-in. PVC pipe is being utilized as the carrier pipe.

The claystone presents a unique soil when considering soil separation plant needs, but that condition combined with the change to alluvium required a multi-pronged approach to soil separation. An existing 42-in. sanitary sewer and 48-in. waterline ran along each side of the microtunnel drive (within less than 3 ft of the launch and receive pits), requiring careful surgical installations of the launch and receive pits.

The project began July 19, 2021, and is estimated to be completed in November 2021. HDR is the engineer, with BTrenchless Inc. the tunneling subcontractor to T. Lowell Construction.

CONNECTICUT

Hartford

South Hartford Conveyance

& Storage Tunnel

CRS Contractors Inc.

This is a $9.1 million project for the Hartford MDC that involves the installation of 5,070 lf of various size pipe by pipe jacking, including microtunneling and pilot tube/guided boring. Tunneling includes two runs of 60-in. OD pipe for a total of 1,136 lf (1,040 ft is the longest); four runs of 52-in. OD pipe for a total of 2,690 lf (1,280 ft is the longest); and three runs of 32-in. OD pipe for a total of 1,242 lf (464 ft is the longest). The microtunneling is in the extremely soft Connecticut Valley Varved Clay. The start date was August 2020, with completion expected by February 2022. The job is currently 75 percent complete. Crews are using a Herrenknecht AVN-1000XC and AVN1200TB, as well as an Akkerman GMB4800 guided boring system. AECOM is the engineer; and CRS Contractors Inc.is the tunneling subcontractor to Empire Paving.

Meriden

Harbor Brook Overflow Culvert

at Amtrak Railroad

CRS Contractors Inc.

This $700,000 project for the City of Meriden DPW includes the installation of two each 80 lf of 73.5-in. OD (72-in. ID) Permalok steel casing pipe by open face pipe jacking under AMTRAK railroad tracks with low cover. In addition to tunneling under the tracks, crews tunneled through existing concrete coal chute. The project began in July 2020 and was completed in September 2020. AECOM was the engineer, and CRS Contractors Inc. was the tunneling subcontractor to Empire Paving.

DELAWARE

New Castle County

Mt. Pleasant Interceptor

CRS Contractors Inc.

This project for New Castle County DPW consists of one 450-ft drive to install 52-in. OD Permalok steel casing jacking pipe by microtunneling under US Route 301 near Middletown. The $1.2 million started in March 2021 and was completed in July. Crews used a Herrenknecht AVN-1000XC M1524M. Black & Veatch was the engineer, and CRS Contractors Inc. was the tunneling subcontractor to Joao Bradley Construction Co.

FLORIDA

Tampa

Harbour Island Force Main Replacement

Bradshaw Construction Corp.

Bradshaw Construction Corp. has begun construction on a design-build project for the City of Tampa, under a congested entrance gate to the Port of Tampa. Bradshaw has since completed one of the 610-lf twin tunnels that are to be mined out of a single 37-ft x 32-ft steel sheeted launch shaft utilizing 73.5-in. steel casing jacked behind a Herrenknecht AVN 1500T MTBM. Ground conditions encountered transitioned from sand to silty clay, and are expected to be consistent for both drives. Once both tunnels are completed, one tunnel will house a 48-in. ductile iron reclaimed water main while the other a 54-in. ductile iron force main. After the ductile iron is installed, it will be backfilled with low density cellular grout. The project is scheduled to be completed in January 2022. Project members include the City of Tampa (Owner), Wade Trim (Design Engineer), Kimmins Contracting (General Contractor) and Bradshaw Construction Corp. working as the tunneling subcontractor. Project Information: Chris Flanagan – Project Manager; CFlanagan@bradshawcc.com.

Tampa

Harbour Island Force Main Replacement Design-Build GMP3, Tampa, Florida.

Harbour Island Force Main Replacement Design-Build GMP3

Vadnais Trenchless Services Inc.

This $28.9 million project for the City of Tampa consists of designing, furnishing and installing a single reach of approximately 3,200 lf of 78-in. OD steel casing by microtunneling with the installation of 54-in. Pressure FRP carrier pipe for a new sewer force main. The microtunnel crossing will be installed using an MTS 1850 primarily in limestone and dense sands beneath the Ybor Turning Basin in North Tampa Bay. The entire tunnel alignment is approximately 55 ft below Tampa Bay.

This project also consists of designing and installing two secant pile shafts approximately 80 ft deep. The jacking shaft will be 40-ft in diameter and the reception shaft will be 20-ft in diameter.

VTS was scheduled to mobilize in April 2021 with a project completion date of November 2022.

Wade Trim Inc. is the engineer. Kimmins Contracting Corp. is the general contractor with Vadnais Trenchless Services as the tunneling subcontractor.

Valparaiso

Eglin AFB Fuel Transfer Line

BRH-Garver Construction L.P.

A new $34 million underground fuel pipeline project is being built at Eglin AFB. Owned and designed by the U.S. Army Corps of Engineer (USACE), Omaha District, the Fuel Transfer Line Replacement project connects the 96th Test Wing storage tank to the 33rd fuel storage area. With the capacity to deliver 600-gpm, the improvement will significantly bolster flying operations and military readiness, with sizeable resource savings.

Reliable Contracting Group LLC was awarded the contract to install 22,300 lf of pipeline and several electrical structures and leak detection system upgrades. BRH-Garver Construction L.P. was awarded the microtunneling contract for the installation of 3,630-lf of steel casing to house 8-in. carrier pipe below the base airfields in seven drives. Slurry microtunneling was the requisite method of installation by the USACE to avoid shutting down Air Force operations. The proposed fuel transfer tunnels would be bored a mere 10-ft below many of the base’s runways and taxiways while surface-level activities resumed as usual.

BRH-Garver crew and equipment mobilized in February 2020. An Akkerman SL30C Slurry Microtunnel Boring Machine (MTBM), with an increase kit to 32-in. outside diameter, was employed to install all seven drives.

Following a project team launch ceremony, crew buried the MTBM head for the first time on March 17, 2020.

The MTBM emerged into the reception pit for the final time on Aug. 25, 2020. BRH-Garver’s crew successfully achieved the line and grade for each tunnel, and the project was completed ahead of schedule. The remaining open-cut footage and pipeline modernization efforts were anticipated for completion in August 2021.

GEORGIA

Athens

Upper North Oconee – Phase 2B Trunk Sewer Replacement

Bradshaw Construction Corp.

Bradshaw Construction Corp. is near completion on construction of a gravity sewer re-alignment project in Athens-Clarke County, Georgia. Two tunnels totaling over 1,300 lf were constructed out of a common launch shaft, utilizing three different tunneling methods. The first tunnel drive spans 116 ft under the Athens Line Railroad, in which 60-in. steel casing was jacked behind a Herrenknecht AVN 1200 MTBM. The second tunnel required two tunneling methods due to a transition in ground conditions. An 8-ft diameter NATM starter tunnel was hand-mined out of the launch shaft until the heading transitioned into competent rock, where a rock head TBM manufactured by Robbins was launched within the starter tunnel, and mined approximately 1,100 ft through competent rock. The rock tunnel curved under a busy section of Georgia SR 10, which eventually mined out into a recovery tunnel that was hand-mined through clay ground conditions just outside of the receiving pit. The TBM was maneuvered through the 9-ft liner plate recovery tunnel toward the receiving pit to complete the drive. In both tunnels, 36-in. ductile iron gravity sewer pipe will be installed and backfilled. The project is scheduled to be completed in November 2021. Project members include Athens-Clarke County (Owner), Garney Construction (General Contractor) and Bradshaw Construction Corp. working as the tunneling subcontractor. Project Information: Chris Flanagan – Project Manager; CFlanagan@bradshawcc.com.

IOWA

Dubuque

Bee Branch Storm Drain Improvements

Huxted Tunneling

The City began planning efforts for this project in 2012, design was completed in 2019, and microtunnel construction was completed in 2020. Huxted Tunneling, the microtunneling subcontractor, used an Iseki Unclemole TCC 1000 MTBM. The storm drain culverts were 101-in. OD by 1.5-in. thick gasketed Permalok steel pipe. Tricon Construction Group was the General Contractor and constructed the complex sheet pile jacking and reception shafts. Strand Associates was the prime design firm and conducted the structural analyses of the shafts and pipe, including measures to protect existing storm drain and railroad facilities. Bennett Trenchless Engineers was the trenchless subconsultant, responsible for microtunneling design and inspection, including evaluation of settlement risks and monitoring program results. The six parallel microtunnels were successfully completed in October 2020. Observed settlements were less than or equal to predicted settlements of about 1.2 in.

The microtunneled storm drain pipelines completed through soft to firm clay, beneath five sets of Canadian Pacific railyard tracks with about 1.5 diameters (10 to 12 ft) of earth cover, consisting of very loose to loose sand fill with fill debris.

MONTANA

Bozeman

Davis Lane Lift Station and Norton East Outfall Sewer Project

Vadnais Trenchless Services Inc.

This $1.9 million job for the City of Bozeman comprised a single drive of 696 lf of 64-in. diameter, 0.75-in. wall Trinity Press Fit Steel Casing. The microtunnel was installed using an MTS 1500 under two frontage roads, and active railroad and four lanes of Interstate 90. The microtunnel progressed through silty, sandy, gravel beneath the groundwater table. It was installed in very difficult ground conditions all under the groundwater table while crossing under on active railroad and six active lanes of traffic. Vadnais Trenchless Services mobilized in April 2021 and completed all work in June 2021. The engineer was HDR Inc. Vadnais Trenchless Services Inc. was the tunneling subcontractor to COP Construction LLC.

OKLAHOMA

Byng

Atoka Pipeline Raw Water Transmission Line Canadian River Crossing | WC-0875

Vadnais Trenchless Services Inc.

This $29.4 million project for the Oklahoma City Water Utilities Trust consists of four microtunneling drives with the installation of 72-in. diameter reinforced concrete pipe and 84-in. diameter reinforced concrete pipe. The total length of all four drives will be approximately 5,700 lf. Upon completion of the microtunneling drives, 72-in. and 60-in. steel carrier pipe will be installed for raw water transmission from the Atoka Reservoir to Oklahoma City. Two 34-ft diameter Central Shafts will be excavated to a final depth of 125 vf and supported by 70 vf of secant pile installation and 55 vf of liner plate installation to shaft bottom. Due to the project’s remoteness, over 5,500 lf of construction road was installed to access the project site.

The slopes for the 84-in. and 72-in. microtunnel drives are 8.6 percent and 7.5%, and 8.6 percent and 8.2%, respectively. Two of the tunnels cross underneath the Canadian River all while tunneling is beneath the groundwater table. Hard rock conditions in the shaft will be excavated using a drill and shoot method. Upon reaching the bottom the shafts, two launch portals, 6 ft deep, will be excavated and supported with steel sets to initiate launching of the MTBM. Crews are using an MTS 1850 and an MTS 2350 MTBMs.

Completion date is currently scheduled for January 2022. The project is approximately 70 percent complete through August 2021. The engineer is Triad Design Group Inc./AECOM. Vadnais Trenchless Services Inc. is the general contractor.

NORTH CAROLINA

Charlotte

Dairy Branch Tributary

Bradshaw Construction Corp.

Bradshaw Construction Corp. continues construction on sanitary sewer tunnels in Charlotte. The 2,399-lf by 60-in. steel casing tunnel will be installed behind a Herrenknecht AVN-1200 MTBM for a 36-in. PVC sanitary sewer. Subsurface conditions consist of granitic rock ranging from 25 kpsi to 38 kpsi and alluvial deposits. Construction started in November 2020 and has completed 608 ft of the 2,399 ft total. The project members include the Charlotte Water (Owner), STV Engineers Inc. (Engineer), B.R.S. Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor. Project Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

Charlotte

Little Sugar Creek Tributary to Central Business District

Bradshaw Construction Corp.

Bradshaw Construction Corp. has started construction on one-pass sanitary sewer tunnels in Charlotte. The 3,587-lf 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 kpsi to 30 kpsi and alluvial deposits. Construction began in September 2020 and has completed 2,660 ft of the 3,587 ft including 1,170 ft of curved 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. Project Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

Charlotte

Upper Little Sugar Creek Trunk Sewer Improvements

Bradshaw Construction Corp.

Bradshaw Construction Corp. 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 is set to begin in November 2021. The project members include the Charlotte Water (Owner), Kimley & Horn (Engineer) Sanders Utility Construction Co. Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor. Project Information: Matthew Webb – Project Manager; mwebb@bradshawcc.com.

TEXAS

Houston

66-in. Water Line Interconnection Along W. Hardy Rd from Beltway 8 To Greens Rd | WBS No. S-000900-0166-4

Vadnais Trenchless Services Inc.

This $2.6 million project for the City of Houston consists of furnishing and installing approximately 855 lf of 84-in. diameter steel casing pipe. This installation will be completed in two separate tunnel drives. The first tunnel drive being 480 lf beneath Beltway 8; one of the largest and busiest highways in the City of Houston, approximately 28 ft deep. The second tunnel drive being 375 lf beneath Greens Bayou, approximately 40 ft deep.

VTS will install welded steel casing utilizing multiple welders simultaneously as required in order to complete the individual tunnel drives within the contracted schedule. The first tunnel drive having both, the launch and reception shafts located along the frontage road of one of the busiest highways in the City of Houston has required extensive coordination with VTS’ suppliers in regard to traffic safety and scheduling around peak traffic times. The second tunnel drive beneath Greens Bayou requires planning and coordination with the general contractor, as well as the Harris County Flood Control District to ensure that the proper controls are in place, monitored and maintained in order to mitigate any negative environmental impact.

VTS began the first tunnel drive on Aug. 9, 2021, and the expected project completion will be on or around Dec. 1, 2021. As of Sept. 1, 2021, the project is 16 percent complete. Aurora Technical Services LLC is the engineer. Crews are using an Iseki TCC1350 MTBM (84-in. ID).

Houston

Abandonment and Flow Diversion of Interwood M.U.D. 266, and Vickery Lift Stations | WBS No. R-000267-121B-4

Vadnais Trenchless Services Inc.

This $14.9 million project for the City of Houston consists of furnishing and installing approximately 4,700 lf of 30-in. diameter sanitary sewer and approximately 3,700 lf of 42-in. diameter sanitary sewer by trenchless method with associated manholes. It is expected that two separate microtunneling crews will be necessary to meet the construction schedule. It includes furnishing and installing approximately 200 lf of 10-in. diameter sanitary sewer line by open-cut and associated manholes.

Following the installation of new sanitary sewer lines, VTS will demo and abandon three city-owned existing lift stations using by-pass diversion pumping. VTS will also abandon, grout and remove 13 manholes, 4,410 lf of 8-in. force main, 160 lf of 10-in. sewer line, 144 lf of 12-in. sewer line, 560 lf of 14-in. force main, 2,200 lf of 16-in. force main, 235 lf of 15-in. sewer line, and 300 lf of 8-in. force main in 14-in. steel casing.

VTS performed a low-end 42-in. sewer line tie-in to a live existing junction box from within the underground tunnel and internal by-passing efforts, which eliminated the traffic control on a busy Lee Rd. and Aldine Bender Rd. intersection.

This project has a schedule constraint and recommends using two tunnel crews to finish the project ahead of schedule and VTS planned accordingly.

Due to the fact that the project is in a high traffic area, extensive coordination as to work hours and access to the local businesses/neighborhood areas has been required. Some tunnels crossed multiple high traffic areas on Aldine Bender Rd. and Vickery Rd. of Houston.

Notice to Proceed was issued to VTS on Oct. 11, 2019, and the project is scheduled to be complete on or around Nov. 19, 2021. As of August 2021, the project is 82 percent complete. 5. Engineer: ARCADIS is the engineer. Crews are using an Iseki TCC600 MTBM (33-in. OD) and an Iseki TCC900 MTBM (45.5-in. OD) for microtunneling.

Houston

Holmes Rd-From Main Street to Kirby Drive | WBS No. N-000590-0001-4

Vadnais Trenchless Services Inc.

This $5.1 million project for the City of Houston consists of installing approximately 3,600 lf of 42-in. diameter FRP Sanitary Sewer and 990 lf of 48-in. diameter FRP Sanitary Sewer. This installation will be completed in five separate tunnel drives all at approximately 30 ft to 35 ft deep. The tunnel drive lengths are 706 lf, 892 lf, 1,000 lf, 1,000 lf, and 990 lf. The entirety of the project is below the natural groundwater table through soils that are saturated with mostly contaminated water.

Due to the high level of contaminated soil saturation there is extensive coordination required with the City of Houston and the General Contractor to provide water-tight shafts and mitigate any potential environmental impacts.

The project is expected to start in early November 2021. OTHON is the engineer. Crews are using an Iseki TCC900 MTBM (42-in. and 48-in. ID).

Houston

WHCRWA Surface Water Supply Project C1 & C2

Bradshaw Construction Corp.

Bradshaw Construction Corp. will soon begin work on Section C1 of the Surface Water Supply Project for West Harris County Regional Water Authority in Houston. This phase of the water transmission line will include two microtunnel crossings totaling 1,020 ft (380 ft and 640 ft). 99.5-in. OD steel casing will be jacked behind a RASA MTBM out of 34-ft diameter liner plate shafts, roughly 55 ft deep. The crossings pass underneath roadways and waterways, through lean clay with sand seams under the water table. The project members include WHCRWA (Owner), Freese & Nichols Inc. (Engineer), Brierley Associates (Engineer), SJ Louis Construction of Texas (GC), and Bradshaw Construction Corp. working as tunneling subcontractor.

Following construction of the C1 crossings, Bradshaw is subcontracted with Harper Brothers Construction (GC) to perform three microtunnel crossings on the C2 phase of the project. These crossings will total 830 ft (270 ft, 380 ft and 180 ft), again with 99.5-in. OD casing jacked behind the RASA MTBM. These crossings will pass underneath three waterways, through lean clay and sand layers under the water table. The tunnels will again be launched and recovered in liner plate shafts.

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

VIRGINIA

Newport News

Morrison Pump Station Discharge Force Main

Bradshaw Construction Corp.

Bradshaw Construction Corp. will soon begin construction on a force main tunnel in Newport News. The single crossing is a 120 lf, 30-in. steel casing tunnel which will be installed underneath CSX railroad tracks with minimal clearance (6 ft). The tunnel will be installed behind a Herrenknect AVN-600 MTBM. Mining will be performed through wet silty sand. The project members include Hampton Roads Sanitation District (HRSD) (Owner), Rummel, Klepper and Kahl LLP (Engineer) Bridgeman Civil Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor. Project Information: Jordan Bradshaw – Project Manager; Jordan.bradshaw@bradshawcc.com.

CANADA

ALBERTA

Calgary

Inglewood Sanitary Trunk

Ward & Burke Microtunnelling Ltd.

Located in Calgary with a construction value of $70 million CAD (approximately $55 million USD), the Inglewood Sanitary Trunk (IST) is the largest microtunneling project completed in the province’s history. The IST project contained four trenchless major railway crossings, and multiple utility crossings.

The project involves a 2,286-/2,500-mm (90-/98-in.) reinforced concrete sewer, which spans approximately 4,000 m (13,000 ft) from the Bow River to the Bonnybrook Wastewater Treatment Plant, the city’s largest wastewater treatment plant. The IST upgrade will provide additional sanitary capacity for a total equivalent population of 1.1 million residents and support growth to the 2076 design horizon.

Phase One was successfully completed, where closed faced slurry microtunneling and sealed shafts were utilized to mitigate constraints and restrictions. This would otherwise have made the construction of a large diameter trunk sewer at this location impractical or near impossible.

Design of Phase Two is currently nearing completion and consists of a twin 400-m – 1,500-mm (60-in.) inverted siphon crossing of the Bow River. Construction is expected to be through trenchless methods and is projected to be completed by 2024.

Whissell Contracting, Ltd., was selected as the general contractor with Ward & Burke Microtunnelling Ltd., retained as microtunneling subcontractor. The contractor mobilized three different Herrenknecht AVNs to site.

Shaft construction to depths of 16 m (52 ft) consisted of seven sunk concrete caissons ranging in diameter from 8 to 11.5 m (26 to 38 ft), and one 11.5 x 8-m (38 x 26-ft) secant pile shaft.

Drive lengths through highly variable soils with high groundwater ranged from 250 to 860 m (820 to 2,822 ft). Most drives contained at least one 500-m (1,640-ft) radius curve, some contained multiple curves and one drive was on an entire curved alignment.

The engineer was AECOM Canada Ltd. The owner was the City of Calgary. The project was completed in November 2020.

ONTARIO

Newmarket

YDSS Force Main Twinning Project

Ward & Burke Microtunnelling Ltd.

The York Durham Sewage System Twinning Project involves building a two-pass microtunnel for a length of 5.5 km. Ward & Burke won the $80 million contract and proposed a revised plan to eliminate two shafts, thereby performing two long drives of 950 m and 1,132 m. Ward & Burke also proposed completing a small open-cut section by microtunneling. All told, Ward & Burke was responsible for seven microtunnel drives, totaling approximately 5,576 m in length. The microtunneling drives – in order of completion – were 818, 731, 501, 641, 821, 950 and 1,132 m.

Centerline tunnel depths varied from 5.5 m to 22 m below ground and the grades throughout were between 1.56 per cent on the initial segment to negative 0.61 percent on the fourth drive. All the sections involved straight segments and curved portions, with the sharpest radius at 435 m. In the Canadian record-breaking 1,132-m drive, the Herrenknecht AVN1800 – one of three remanufactured AVN1800s on the project in addition to an AVN1200 – navigated a horizontal curve of 500-m radius over 228 m and a flat continuous grade of 0.02 percent.

Ward & Burke’s work was slated to be completed by July, with the new system operational by the end of the year. GHD and Black & Veatch are the engineers. The Regional Municipality of York is the owner. DECAST was the pipe suppler.