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Trenchless Technology’s 2020 Microtunneling Job Log

Trenchless Technology’s annual Microtunneling Review section highlights the projects and developments in the microtunneling market.



Marina Del Rey

Venice Dual Force Main and Venice Pumping Plant Generator Replacement Project

Vadnais Trenchless Services

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launch in Marina Del Rey

This project involves the construction of a new 54-in. diameter force main sewer extending approximately 10,392 lf in length, which originates from a newly constructed manifold adjacent to an existing pumping plant. From the manifold, the alignment will proceed east, then southeasterly and cross beneath the Marina Del Rey and Ballona Creek channels, continue traveling south within Pacific Avenue and end at the Coastal Interceptor/North Outfall Sewer (CIS/NOS) junction structure.

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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 900 lf.

The project also consists of the demolition of the existing equipment and procurement and installation of 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.

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This entire project is unique. The entire alignment and large scope of work 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 summer 2021. The project was 75% complete at the end of October 2020.

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Owner: City of Los Angeles Department of Public Works; Engineer: City of Los Angeles Engineering. Equipment: MTS 1500 Microtunnel System (70-in. OD), MTS 1650 Microtunnel System (70-in. OD), MTS 1850 Microtunnel System (80-in. OD). Contract value: $88,893,730.00.

Mission Viejo

Potable and Recycled Pipeline Replacements at I-5 and Oso Creek

Vadnais Trenchless Services

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This project consisted of one microtunnel drive totaling 410 lf of 72-in. OD Permalok steel casing. The steel casing contained a 20-in. FPVC potable water main incased in a 30-in. FPVC secondary casing and a 30-in. FPVC recycled water main encased in a 36-in. FPVC secondary casing.

This project also contained a pilot tube auger bore totaling 120 lf of 30-in. welded steel casing. The steel casing contained a 12-in. FPVC potable water line.

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Shafts for the microtunneling were between 35 and 22 ft deep and were water tight, sheet pile construction. The microtunnel and pilot tube auger bore utilized a single, common receiving shaft.

The project also consisted of open-cut for both the potable and recycled water lines with tie ins to existing lines, abandonment of failing potable and recycled water lines that run under I-5, and restoration of a private golf course.

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This project was unique for multiple reasons. First, the 72-in. Permalok steel casing contained both a potable and recycled water lines housed in secondary casings. The common receiving shaft and PTAG jacking shaft was inside the Mission Viejo Country Club, which required extensive communication, planning and a joint effort by all stake holders to maintain play at all times. The 72-in. microtunnel crossed I-5 underneath an overpass in close proximity to existing piles and with limited cover. Coordination with Caltrans was imperative to keep the project on schedule.

The job is complete. VTS mobilized in mid-September 2019 and completed all work in August 2020.

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Owner: Moulton Niguel Water District; Engineer: GHD; Equipment: Iseki TC 1350 72-in. OD; Contract value: $7,245,000.00.


Brown Valley Trunk Project

Vadnais Trenchless Services

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This project consists of a 273-lf microtunnel drive of 48-in. OD welded steel casing and a 283-lf PTAB drive of 30-in. OD welded steel casing. Shafts for the microtunneling will be between 18 and 23 ft deep and will be of watertight, sheet pile construction. The microtunnel will be installed primarily in lean clay material, with trace sand and gravel. The tunnel will be installed up to 10 ft below the groundwater table. The site has tight working areas and heavy traffic.

The PTAB crossing was completed in early October 2020 and the balance of microtunnel work is scheduled to be completed by mid-December 2020.

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Owner: Napa Sanitation District; Prime Contractor: JMB Construction; Engineer: GHD Inc. Equipment: Iseki TCC1000 Microtunnel (48-in. OD). Contract value: $1,250,720.00.

RELATED: Vadnais Trenchless Stays Focused on Microtunneling

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San Carlos

SVCW Belmont Gravity Pipeline – Design Build

Vadnais Trenchless Services

This project 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.

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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 US 101 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.

Vadnais anticipates a mobilization date of June 2021, with an estimated completion date of fall/winter 2022. Crews plan to use an Iseki TCC800 MTBM (38.5-in. OD) for this $9.844 million project.

Owner: Silicon Valley Clean Water; Prime Contractor: J.F. Shea/Parsons, a Joint Venture; Engineer: J.F. Shea/Parsons, a Joint Venture.

Santa Cruz

Coast Pump Station Raw Water Pipeline Replacement

Vadnais Trenchless Services

This project consists of a single drive of 221 lf of 42-in. diameter (0.625-in. wall) Permalok steel casing. The microtunnel will be installed under the San Lorenzo River from a 72-ft deep jacking shaft and into a 51-ft deep receiving shaft. The microtunnel will progress through three soil formations 15,000 psi quartz diorite, weathered schist and finally flowing sandy gravel with cobbles. Maximum anticipated water head is 37 ft.

The microtunnel and shafts are deep with multiple soil and rock formations. The microtunnel will be installed under an environmentally sensitive water way.

Work started in May 2020 and was 80% complete as of October 2020. Microtunneling is expected to be complete in early-November 2020. The overall project is scheduled to be complete in February 2021.

Owner: City of Santa Cruz; Engineer: Kleinfelder; Equipment: Iseki TCS900 Super Mole, 42-in.; Contract value: $4,693,675.00.


V-1 West Vista Way Sewer Phase 1

Vadnais Trenchless Services

This project consisted of two microtunnel drives totaling 675 lf of 42-in. OD Permalok steel casing with 15-in. PVC carrier pipe. Shafts for the microtunneling were between 32 and 25 ft deep and were beam and plate construction. The microtunnel was installed in the Santiago formation consisting of weakly to moderately cemented sandstone and weakly to moderately indurated siltstone.

The tunnels were installed from one common jacking pit to two different receiving pits. Both tunnels were under heavily traveled roads and under high cover with limited work area and overhead powerlines.

The job is complete. VTS mobilized in January 2020 and completed all work in early-April 2020.

Owner: City of Vista; Prime Contractor: Orion Construction Corp.; Engineer: KEH & Associates Inc.; Equipment: Iseki TCS 900 (42in. OD); Contract value: $1,282,375.00.



Fitzsimons-Peoria Stormwater Outfall Project


The Fitzsimons-Peoria Stormwater Outfall Project has utilized a collaborative delivery process through CMGC to replace undersized 1950s storm drain infrastructure in a congested area of Aurora, Colorado. The owner, design team, and contractor have been able to collectively select the best tunneling method to lower owner risk and to increase the chances of success based on the challenging soils and site constraints anticipated on the tunnel drives.

The owner’s understanding of subsurface risk allowed for a thorough subsurface investigation during design which identified clayey eolian deposits, residuum with claystone as a parent material, and clay fill that included pockets of squeegee sand within the project’s first major work area. The presence of groundwater was anticipated during the tunnel drives and launch pit construction. The entire project includes more than 13,000 lf of large diameter pipe outfall with four grade critical trenchless crossings utilizing both TBM and MTBM methods. The most challenging trenchless installations were the crossings of Colfax Avenue (a 6-lane road) at edge of the Peoria Street (a 6- to 8-lane road) intersection with a 72-in. and 48-in. pipelines utilizing a microtunneling method with very limited laydown area for launch pits and a construction site.

The project team found room for a 30 ft diameter, 30 ft deep tunnel launch pit in the northeast turn lane of the intersection. This pit would later serve as the shoring system for the cast-in-place concrete junction structure designed to tie the two lines together. This pit required temporary relocation of a 42-in. storm sewer and permanent relocation of two different fiber systems. BTrenchless utilized an Akkerman SL74 MTBM with a 75.4-in. skin kit and an SL51 MTBM for the 72-in. and 48-in. drives, respectively. An MT875K – Keyhole Jacking Frame with skid extensions was used to advance both tunnel drives.

Project Owner: Aurora Water Department; Engineer: Carollo Engineering; Contract Value: $6,651,310.

RELATED: Denver Metro Projects Accommodate Urban Expansion


Zone 3: 24-in. E. 56th Ave. Pipeline from Picadilly to Harvest

Vadnais Trenchless Services

Aurora Zone 3 in Colorado

This $1.4 million project for the City of Aurora consisted of a 958-lf microtunnel drive of 48-in. OD Permalok steel casing with 36-in. welded steel waterline carrier pipe. Shafts for the microtunneling were between 32 and 36 ft deep and consisted of watertight, liner plate construction. The microtunnel was installed primarily in claystone bedrock material, with a pocket of fat clay of approximately 150 ft. The tunnel was installed above the groundwater table.

This tunnel was installed beneath E-470, just south of Denver International Airport in the City of Aurora. Cover over the casing crown ranges from 8.5 to 32 ft. Unanticipated seams of very hard sandstone complicated the crossing.

The job is complete. Vadnais mobilized in late April 2020 and completed all work in July 2020. The prime contractor was Garney Construction. The engineer was Dewberry Engineers Inc. Vadnais used an Iseki TCC1000 Microtunnel (48-in. OD) for tunneling.



Harbour Isalnd Force Main Replacement Design-Build GMP3

Vadnais Trenchless Services

This project 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 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 70 ft deep. The jacking shaft will be 40-ft in diameter and the reception shaft will be 20-ft in diameter. This is extremely long (3,195 LF) microtunnel reach is almost entirely beneath Tampa Bay.

VTS is scheduled to mobilize in April 2021 with a project completion date of October 2022.

Owner: City of Tampa; General Contractor: Kimmins Contracting Corp.; Engineer: Wade Trim Inc.; Equipment: MTS 1850 Microtunnel System (80-in. OD). Contract value: $28,964,986.00.


Fuel Transfer Line Replacement


Valparaiso, Florida

BRH-Garver installed 3,630 lf of 32-in. steel casing by microtunneling for the installation of a new jet fuel transfer line at Eglin Air Force Base. The work consisted of seven separate drives installed beneath existing active taxiways and runways used by the USAF 96th Logistics Readiness Squadron. Installation by slurry microtunneling was required by the owner, the U.S. Army Corps of Engineers, to avoid shutting down operations. This essential project was completed one month ahead of schedule during the COVID-19 pandemic while keeping our healthy and productive.

The $5.65 million project began in February 2020 and was completed in August 2020. The average drive was 550 lf with the longest drive 640 lf. Crews used an Akkerman SL-30 MTBM.



Upper North Oconee – Phase 2B Trunk Sewer Replacement

Bradshaw Construction Corp.

Bradshaw Construction has begun construction in Athens-Clarke County for re-alignment of the gravity sewer line. Bradshaw has just completed the first tunnel drive spanning 116 ft under the Athens Line Railroad, in which 60-in. teel casing was jacked behind an AVN 1200 MTBM. The second tunnel will require two separate tunneling methods due to a transition in ground conditions. A NATM starter tunnel will be excavated out of the shaft until it becomes too difficult to proceed, where a rock head TBM manufactured by Robbins will take over and mine approximately 1,100 ft through competent rock. The rock TBM will curve under a busy section of GA State Route 10, and be recovered in a liner plate recovery tunnel and maneuvered into the receiving pit. After both tunnels are complete, 36-in. ductile iron gravity sewer pipe will be installed and backfilled. Ground conditions are anticipated to transition between partially weather rock and granite. The project is scheduled to be completed in March 2021. Project members include Athens-Clarke County (Owner), Garney Construction (General Contractor) and Bradshaw Construction Corporation working as the tunneling subcontractor. Project Manager: Chris Flanagan.


Niles Avenue Sewer Improvements

Bradshaw Construction Corp.

Bradshaw Construction is currently working on a project, contracted under Garney Construction, in the suburbs of NW Atlanta for the Department of Watershed Management to realign an existing 15-in. sewer line. Bradshaw is expected to install 1,760 lf of 18-in. ductile iron sewer pipe by trenchless means in difficult geotechnical conditions that warrant both the use of a Robbins Rockhead Double Shielded TBM and a Herrenknecht MTBM.

Bradshaw has completed the installation of four liner plate shafts ranging in size and geology, and has started mining on three separate tunnels utilizing both the TBM and MTBM. The Robbins TBM has finished mining through a 1,000-ft radius curve in a bald rock tunnel spanning a total distance of 713 lf. Bradshaw also completed mining with the MTBM simultaneously, which spanned a distance of 346 lf in mixed ground conditions. The last tunnel, 701 lf, combines the use of both tunnel boring machines. The MTBM was launched 415 lf one direction into wet silty clay, while the Robbins TBM launched in the opposite direction to receive the MTBM within the rock portion of the drive. The Robbins machine will be backed up into the shaft and the MTBM will be jacked the remainder of the way. Once complete, 18-in. DI pipe will be installed and backfilled. Construction was expected to be complete by October 2020. Project Manager: Chris Flanagan.


Oak Lawn

Water Transmission Main Bid Package 6A

Super Excavators Inc.

The proposed new transmission main program for the Village of Oak Lawn is divided into seven bid packages. BP6A includes approximately 5 miles of 60-in. diameter pressurized steel water main. The seven bid packages together will provide additional capacity and redundancy for the water supply to the Village and its customer communities. The General Contractor for BP6A is Reliable Contracting and Equipment Co., with Super Excavators Inc. performing the trenchless work.

The pipeline installation in BP6A includes three tunnel crossings; at the Cal-Sag Channel from Station, 414 lf with 65 vf max depth; the Norfolk Southern Railroad easement, 310 lf with 65 vf max depth; and at Tinley Creek from Station, 755 lf with 52 vf max depth. The tunnels are all being constructed with an 88-in. outside diameter steel casing by microtunneling. The tunnel crossing for the Cal-Sag Channel will be excavated in bedrock with the other tunnels excavated within the overlying soils. The MTBM being utilized for the tunnel crossings is an upsized Akkerman SL-74.

The Norfolk Southern Railroad (310 lf) and the Cal-Sag Channel Crossing (414 lf in bedrock) were successfully completed in summer 2020. The Tinley Creek Crossing is planned to be completed in spring 2021.

The Cal-Sag Crossing was completed in dolomite limestone with UCS up to 20,000 psi with a MTBM outfitted with a custom disc cutterhead designed and fabricated by Akkerman, outfitted with Robbins 11.5-in. diameter disc cutters.

NTP was issued July 29, 2019. Final completion is expected by March 10, 2023.

Owner: Village of Oak Lawn; Tunnel Designer: CDM Smith; MTBM Manufacturer: Akkerman; Casing Pipe Manufacturer: Permalok; Contract Value: $56,471,266.

Key Project Personnel: Super Excavators – Tim Benson, Project Manager; Brain Strane, Tunnel Project Superintendent.



SR 37 Offsite Drainage Outfall Storm Sewer – North Segment

Super Excavators Inc.

The $21.6 million project, owned by the Indiana DOT, is part of the SR 37 Improvement Project, Phase 1 in Fishers, a suburb of Indianapolis. It involved constructing two offsite drainage outfall storm sewers to address roadway drainage to dispense into natural surface water bodies between the 126th to 146th Street corridors.

The SR 37 Improvements Project is in fast-growing Hamilton County. It features at-grade intersections to be redesigned as underpasses, interchanges, and roundabouts to maintain traffic flow along SR 37, alleviate congestion, and encompasses long-term growth. Midwest Mole Inc. (MWM) of Fishers, IN, was awarded the SR 37 Improvement Project Phase 1. MWM was responsible for the two drainage outfall system sewers, site access construction, building a detention pond and outlet, and site restoration. MWM embarked on the south section drainage tunnel in October 2018 with a closed-face TBM to excavate a 2,100-lf, 84-in. tunnel that ran from SR 37 to Lantern Rd. between 126th and 131st Sts., made of steel beams and wood lagging, with 54-in. ID Hobas final liner.

The geology became unconducive to the technology, and at 1,100-lf of 2,100-lf, unanticipated ground conditions were encountered, and MWM determined that completion by microtunneling was necessary. As a subcontractor to MWM Super Excavators Inc. (SEI) of Menomonee Falls, WI, executed the installation of the second drainage outfall via microtunneling in the north section. SEI used their Akkerman SL60C MTBM system with a mixed-face disc cutter head, and their AZ100 TGS system for tunneling navigation.

Original microtunneling footage comprised 4,285-lf of 54-in. ID RCP pipe with inverts up to 44-ft below grade. Microtunneling work began in August 2019. The first run was finished in September 2019, a record 1,966-lf for this diameter Akkerman MTBM. Completion of the south TBM tunnel added 1,000-lf of microtunneling work under a car dealership with only 15-ft of cover. An additional 660-lf was added by change order for future connection.

In February 2020, SEI beat that record with the fourth and final alignment – a 2,304-lf curved, 54-in. ID RCP tunnel. This tunnel was the most complex, had the highest amount of water pressure, and featured a 1,975-lf straight section with a 329-lf curve and 1,929-ft radius. At completion, the total microtunneling footage was 5,920 lf, in 1,966-, 1,000-, 650- and 2,304-lf lengths, and installed with precision line and grade accuracy.

Project Owner: Indiana Department of Transportation; Engineer: Indiana Department of Transportation Contractor: Midwest Mole Inc. (prime) – Super Excavators Inc. (microtunneling subcontractor); Contract value: $21.6 million

RELATED: 2020 Project of the Year New Installation Honorable Mention: SR 37 Offsite Drainage Outfall Storm Sewer – North Segment


CSO-13 Consolidation Sewer – Phase II

Bradshaw Construction Corp.

Bradshaw Construction Corp. completed construction of two 60-in. FRP tunnels for a sewer installation in Indianapolis. The 63-in. OD tunnels, the first 107 ft and the second 380 ft, were installed behind an up-skinned Herrenknecht AVN-1200 MTBM. Ground conditions consisted predominantly of sand, silt and gravel, with periodic zones of cobbles. The tunnels passed underneath West Street and existing utilities with minimal clearance. The project was completed in August 2020. The project members included Citizens Energy Group (Owner), AECOM/The Etica Group (Engineers), Reynolds Construction LLC (General Contractor) and Bradshaw Construction Corp. working as tunneling subcontractor. Project Manager: Jordan Bradshaw.



Shady Grove Sewer Extension Tunnel

Bradshaw Construction Corp.

Bradshaw Construction is beginning construction on a sewer extension project for a new development in Derwood. The 48-in. RCP, 190-ft tunnel will be installed behind a Herrenknecht AVN-1200 MTBM underneath Crabbs Branch Way. Tunnel geology will consist of rock with UCS ranging up to 27 ksi. The tunnel will pass underneath the highway and sensitive utilities. Once complete, 16-in. DIP will be installed and backfilled. The project members include EYA Developers (Owner) and W.F. Wilson (General Contractor), with Bradshaw Construction Corp. working as tunneling subcontractor. Project Manager: Jordan Bradshaw.



Port-PL6 Stormwater Storage Tank Tunnel


The Port-PL6 Stormwater Storage Tank Tunnel project involved the installation of a 70-in. OD steel case pipe advanced through difficult ground conditions for a length of 195 lf near Lafayette Square in Cambridge, MA. There were multiple hurdles to overcome in planning, including ground conditions comprised of weight-of-hammer Boston blue clay, the tunnel path advancing just 6.5-ft below a Massachusetts Bay Transportation Authority (MBTA) structure and adjacent to other nearby buildings, along with the fact that the City of Cambridge sits at just 39-ft above sea level. To combat these issues, a RASA DT 1500 slurry MTBM was selected for a one-pass advancement. Initial alignment planned for tunneling at a lower depth but after boring samples were collected along the tunnel alignment, it was determined that there was a lens of sand interlayered between the Boston blue clay approximately 18- to 20-ft above the initial alignment that would be better suited for tunneling. The differences between advancing through sand vs. clay were enormous, and by utilizing the sandy-clay layer it provided less hydraulic conductivity and shear strength, much less clogging potential and instead of a squeezing effect which would certainly occur in all clay, the MTBM would more likely encounter a raveling or running effect which could be managed by the operator. To combat the MTBM’s natural desire to dive and lose shear strength of material at the face, possible solutions included increasing the penetration rate (jacking speed), reducing slurry flow and pressure to minimize hydraulic disturbance, if possible, and decreasing the cutter head speed to minimize disturbance. An experienced operator was mandatory for the work performed by SECA Underground to achieve success on the project. The area of highest concern in regard to tunnel alignment was at the approximately 150-ft advancement mark where the MTBM advanced just 6.5-ft below the MBTA Redline subway tunnel. With little ground settlement allowance, it was imperative that the operator maintain line and grade throughout tunneling operations to minimize the potential for alignment and grade tolerance to exceed 1-in. per 50-ft. SECA executed the tunneling precisely resulting in an alignment that was within 1/8th inch of the target line and grade. The project was completely successfully and delivered on time and on budget.

Project Owner: City of Cambridge Department of Public Works; Engineer: Kilduff Underground Engineering Inc.; Contract Value: $2.5 million.



Davis Lane Lift Station and Norton East Outfall Sewer Project

Vadnais Trenchless Services

This $1.99 million project consists of a single drive of 696 lf of 64-in. Trinity Press Fit Steel Casing (0.75-in. wall). The microtunnel will be installed under two frontage roads, an active railroad, and four lanes of Interstate 90. The tunnel will progress through silty, sandy gravel underneath the groundwater table with ground improvements planned for under the railroad.

Mobilization is scheduled for April 2021, with completion expected by June 2021

Project owner: City of Bozeman; general contractor: COP Construction LLC; engineer: HDR Inc. Crews will use an MTS 1500 MTBM (64-in. OD).



Schoharie Reservoir Low Level Outlet

Southland/Renda JV

This $142.6 million project for NYC DEP comprises two 9.5-ft microtunnels: a 1,225-ft land leg drive and a 950-ft water leg drive with wet retrieval from the bottom of reservoir at a depth of 160-ft. Both microtunnels are complete. An unplanned extensive rebuild of the machine was required between the two drives due to significant wear of both internal and external parts. Both line and grade were within tolerance for both tunnel drives. Wet retrieval required an adjustment to the original planned operation necessitating field adjustments to the means and methods.

The shaft has been concrete lined to near the top and the wheel mounted roller gate frames installed and dry fit. Work is ongoing on the concrete gate guides that extend from the bottom of the shaft to the maintenance floor 140-ft above. Once complete, shoring will be installed and the maintenance and hoist floor cast followed by the remainder of the circular building aboveground. The concrete for electrical enclosure adjacent to the gate shaft is nearly complete and the masons will start the bluestone cladding by the end of September.

After retrieval, the adaptor was cut off the Permalok pipe by divers and the 90-degree elbow and intake set and welded onto the tunnel pipe by way of a buttstrap connection. The underwater cofferdam was then filled with tremie concrete to just below the bellmouth and a plug installed so that the tunnel could be dewatered. A 25-ft tall 12-sided inlet screen made of 316 stainless steel was then positioned over the intake with 1 ft below the top of the bellmouth and tremie concrete placed to lock it in place. A hatch at the top will allow for removal of the plug at the end of the project and also allow for installation of the plug in the future for maintenance and inspection. All marine equipment has been removed from the reservoir and demobilized.

After removal of the marine equipment from the reservoir, the temporary sheeting for the marine staging area was removed and stacked rip rap placed along the bank leading up to the East Overlook area. The East Overlook will be a visitor center open to the public for viewing and history of the dam. Footers and walls have been placed for the majority of the retaining walls and the interpretive center. Masonry work will begin shortly along with piers for the pedestrian bridge and additional architectural finishes. Civil work including two bio-retention cells, storm drains and other permanent erosion control have been installed. Bridge erection, sidewalks and paving will follow.

The valve chamber building, a 3-story cast in place building with slabs up to 10-ft thick and walls up to 6-ft thick utilizing colored concrete and an aggressive formliner to match the face of the dam, is more than 70 percent complete with both 78-inch knife gate valves, ultrasonic flow meters and cone valves in place. The embedded stainless steel plates are installed in the hood structure with minor welding remaining before installation of the dissipator baffle plates. Shoring is in place for the upper levels and the stair tower base slab has been installed. Once the shell is complete, the remainder of the mechanical and electrical systems will be installed followed by the architectural finishes.

The wing walls used to protect the building from high flows are complete along with the walers, 33 tiebacks and majority of concrete encasement. Most of the concrete used on the project is colored and textured to mimic natural stone.

The RCC berm has been covered with topsoil and will be seeded in the coming weeks. Permanent erosion control features have also been installed in this area as well. The remainder of the stream restoration will be next spring following the end of the Bald Eagle breeding season.

NTP was issued June 29, 2015. The estimated date of completion is December 2021.

Other Major Parties Affiliated with the Project: DEP AM, Emory Chase; Project Designer (Gannett Fleming/Hazen Sawyer), Everette Knight; Resident Engineer (AECOM), Patrick Hoosier; MTBM Manufacturer, Herrenknecht.

Key Project Personnel: SRJV Project Manager, John Arciszewski; Field Operations Manager, Chris Davis; Project Engineers, Tim Bray, Joe Janke, Ammar Fallaha, Christy Ellis; Superintendent, Douglass Somers; Safety Manager, Jose Perdomo.



Dairy Branch Tributary

Bradshaw Construction Corp.

Bradshaw Construction will be starting 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. sanitary sewer. Subsurface conditions consist of granitic rock ranging from 25 kpsi to 38 kpsi and alluvial deposits. Construction is scheduled to be begin June 2020. 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;


Little Sugar Creek Tributary to Central Business District

Bradshaw Construction Corp.

Bradshaw Construction will be starting 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 is scheduled to be begin June 2020. 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;



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

Vadnais Trenchless Services

This $29.48 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% and 7.5%, and 8.6% and 8.2%, respectively. Two of the tunnels cross underneath the Canadian River all while tunneling beneath the groundwater table. Hard rock conditions in the shaft will be excavated using a drill-and-shoot method. Upon reaching the bottom of the shafts, two launch portals 6-ft deep will be excavated and supported with steel sets to initiate launching of the MTBM.

The project completion date is currently scheduled for Sept. 23, 2021. The project is approximately 35% complete through October 2020.

The engineer is Triad Design Group Inc. and AECOM. Vadnais is using an MTS 1850 MTBM (72-in. RCP) and MTS 2350 MTBM (84-in. RCP) for tunneling.

Oklahoma City

OKC Sanitary Sewer Relief Interceptor SC-0950

Bradshaw Construction Corp.

Bradshaw Construction recently completed constructing three tunnels as part of a sanitary sewer installation in Oklahoma City. The three drives totaling 902 ft of 90-in. welded steel casing tunnel were installed behind a RASA DH-1900 MTBM. Mining conditions varied between sands, silts and clays of various stiffness and density, all under the water table. Drives ranged from 167 to 540 ft, traversing under I-35 and BNSF railroad crossings. Soldier pile and steel plate launch and recovery shafts and 72-in. FRP were installed by the General Contractor. Construction began in February 2020 and concluded in late May 2020. The project members included the Oklahoma City Water Utilities Trust (Owner), Cabbiness Engineering (Engineer), McKee Utility Contractors Inc (General Contractor) and Bradshaw Construction performing as tunneling subcontractor. Project Manager: Jordan Bradshaw.



Hilltop Energy Center LLC Water Intake Tunnel

Bradshaw Construction Corp.

Bradshaw Construction Corporation recently completed construction on this raw water intake tunnel. The 330-ft by 60-in. welded steel casing tunnel was installed behind a Herrenknecht AVN-1200 MTBM. Mining began in 25 ksi limestone and progressed into dense river alluvium before the drive was terminated in the Monongahela River. Following MTBM recovery, Bradshaw is currently installing a 24-in. HDPE carrier pipe, three 2-in. stainless steel air discharge lines, and will backfill grout the tunnel once complete. Construction was scheduled to be completed by the end of May, 2020. The project members include Kiewit Power (Owner), Hilltop Energy Center LLC (Engineer) Garney Companies, Inc (General Contractor) and Bradshaw Construction performing as tunneling subcontractor.



Joes Creek Interceptor

Southland Contracting Inc.

This project consists of 8,370 lf of 60-in. excavated diameter tunnel to house 36-in. Hobas carrier pipe. There are 20 shafts ranging from 21 to 48 vf in depth. Ground conditions comprise sand, sand with gravel, sandstone, sandy clay, shaley clay, and shale (Eagle Ford). Tunneling is done by three methods: 60-in. Herrenknecht microtunnel boring machine (MTBM), 76% of job; 60-in. double-shield, open-faced, rigid, steering-shoe guided TBM (designed and fabricated by Southland Holdings), 23% of job; and 54-in. casing by jacking and hand mining, 1% of job.

Crews have completed excavation of 15 of 21 shafts and 14 of 17 tunnels (73% of tunneling by footage). They are installing carrier pipe and manholes, backfilling shafts as they go. Complicating the job is the fact that 19 of 21 shafts are in high-traffic streets of Dallas. Crews also successfully completed a 1,256-lf microtunnel drive of 60-in. pipe within 1/16-in. of centerline despite drastically changing soil conditions.

Owner: City of Dallas; Lead Designer: Hazen and Sawyer; CM: City of Dallas; TBM Manufacturer: Southland Contracting, Herrenknecht; Contract value: $15.8 million.

Key Project Personnel: SCI –Operations Manager: Kent Vest; Project Manager: Elliott Fuller; Senior Engineer: Fareed Imoro; General Superintendent: Homero Lugo


Permian Highway Pipeline – James River Direct Pipe Installation

Michels Corp.

Michels Corp. is in the process of completing a Direct Pipe installation for Kinder Morgan’s Permian Highway Pipeline. The project comprises the installation of 2,076 ft of 42-in. steel pipeline in mixed rock conditions: limestone, chert, karst, clay seams, dolostone, and marl. A Herrenknecht AVN800XC (42-in. Direct Pipe microtunnel boring machine) is being utilized along with a 750-tonne pipe thruster. The project was 30% complete as of Sept. 11 with 633 ft of pipe installed.

Owner: Kinder Morgan; Prime Contractor: Pumpco; Trenchless Contractor: Michels; TBM Manufacturer: Herrenknecht; Inspection/Engineering: GeoEngineers; Designer: Michels Corp.

General Manager: Brandon Young; General Superintendent: Eric McBrair; Senior Project Manager: Chip Myers; Engineer: Tucker Toelke; MTBM operator(s): Johnie Halkyard, Kirk Randles; Field Engineers: Hailey Edlebeck, Ryan Ward; Safety: Mike Simpson; Field Supervisors: Victor Molla, Chad Stoneburner, Seth Freiberg.


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

Vadnais Trenchless Services

This project 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. Also, 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. Also, abandoning, grouting and removing 13 manholes, 4410 lf of 8-in. force main, 160 lf f 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 plan to perform a low-end 42-in. sewer line tie-in to live existing junction box from within the underground tunnel and internal by-passing efforts, which will eliminate the traffic control on a busiest 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 has 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 will be required. Some tunnels will cross multiple high traffic areas on Aldine Bender Rd. and Vickery Rd. of Houston, TX.

Notice to Proceed was issued to VTS on Oct. 11, 2019, and the project is scheduled to be complete on or around June 2, 2021. As of October 2020 the project is 37% complete.

Owner: City of Houston; Engineer: ARCADIS; Equipment: Iseki TCC600 MTBM (33-in. OD); Iseki TCC900 MTBM (45.5-in. OD); Contract Value: $14,946,321.58.


Chelford City Diversion Package No.1: 60-in. Sanitary Sewer


Chelford City, Texas

This project consisted of the new installation of 4,634 lf of 60-in. FRP gravity sanitary sewer by microtunneling and boring methods along and within the right-of-way of Westpark Drive, from Ashton Park Dr. to W. Houston Center Blvd. The completed tunnel will include a large cast-in-place concrete junction structure at the downstream end connection to the existing 108-in. sewer tunnel in W. Houston Center Blvd. Installation of this structure will require the relocation of 115 lf of 54-in. RCP storm sewer and 30 lf of 24-in. storm sewer. It will also include 10-ft and 12-ft polymer concrete manholes, and will include three “stub-out” lines, terminating at 10-ft polymer concrete manholes. The “stub-outs” shall be 48-in F RP gravity sanitary sewer by microtunneling, a total length of 351 lf.

The owner is the City of Houston. The designer is Hazen & Sawyer. The $15.9 million project began in October 2019 and is scheduled for completion in August 2021. Crews are using a Herrenknecht 1200TB to install the Hobas pipe. The average drive length is 1,043 lf, with the longest drive being 1,583 lf.


Fountain View Lift Station


Construction of thos $25.5 million project included construction of the Fountain View Regional Lift Station and the demolition of the existing Westheimer No. 1 Lift Station. It involved approximately 4,070 lf of 36-in. diameter force main and approximately 4,000 lf of 48-in. diameter gravity sanitary sewer by microtunneling. The project consists of over 1.5 miles of utility construction in one of the busiest districts in Houston where trenchless is the best solution.

The owner is the City of Houston. The designer is Amani Engineering Inc. The project began in May 2020 and is expected to be complete by January 2022. Equipment includes an Akkerman SL-44 and Herrenknecht AVN. Crews will install a total of 3,886 lf of 48-in. Hobas pipe (average drive: 950 lf, longest drive: 1,095 lf), as well as one 195-lf drive of 66-in. Permalok pipe.


Holmes Rd. Sanitary Sewer from Kirby to Knight Rd


This project consisted of the installation of new 48-in. sanitary sewer lines and 8-ft sanitary sewer manholes as well as the construction of a 20-ft diameter junction box structure at 32-ft deep on average. The work is 100% in a potentially petroleum contaminated area (PPCA), which requires monitoring and testing for special handling of ground water and tunnel spoils.

Crews used an Akkerman SL-44 to install a total of 4,372 lf of 48-in. Hobas pipe. The average drive was 800 lf with the longest drive being 940 lf.

The project owner in the City of Houston. The designer is Othon Inc. The $8.5 million project began in July 2018 and was completed in January 2020.


Sanitary Sewer Improvements – George Bush Intercontinental Airport

Super Excavators Inc.

The project includes replacement of existing 18-in. diameter sanitary sewer line from Terminal A to Chanute Lift Station with 24-in. diameter pipe. The proposed invert depths of the sanitary sewer line will range from 20 to 23 ft below existing grade. The new sanitary sewer line will cross beneath multiple taxiways and runways within George Bush Intercontinental Airport. The majority of sewer is planned for installation in a primary lined tunnel with portions planned for open cut. The primary liner consists of 5,594 lf of 48-in. RCP lined with 24-in. fiberglass reinforced pipe. There is approximately 804 lf of 24-in. fiberglass reinforced jacking pipe installed utilizing a guided boring method. There are 12 shafts on the project varying in sizes from 14, 18 and 24-ft foot dimeter with depths of an average of 23 ft below existing ground level.

The work has commenced on the project and six shafts have been completed for segments one and two following the project phasing plan. Currently, the MTBM completed the first 2,168 lf tunnel drive under multiple runways and taxiways. The MTBM crew is loading and grouting the carrier pipe and will begin the setup at the next mining shaft starting November 2020. The GBM work on segment one is 100% complete and, following the completion of the GBM work, the associated MH installations and shaft backfilling is occurring.

A significant amount of coordination and planning must take place to perform the work inside an active airport system. NTP was issued May 18, 2020. Final completion is expected by summer 2021.

Owner: Houston Airport System – City of Houston Department of Aviation; MTBM Manufacturer: Akkerman; Primary Tunnel Liner: Forterra; Carrier Tunnel Pipe: Hobas; Contract value: $19,045,210.00.

Key Project Personnel: Super Excavators – Mike Garbeth, Senior Project Manager; Francisco Garcia, Project Manager; Jay Esser, Project Superintendent; Nate Weidmeyer, Tunnel Project Superintendent; Dave Jacobson, Project Foreman; Dave Gauerke, Safety Manager.


Sleepy Hollow and Telephone Road No. 1 Lift Stations


Sleepy Hollow, Texas

This $12.69 million project consists of the construction of approximately 4,128 lf of 36-in. diameter gravity diversion sewers, manholes, one sanitary junction box on an existing 66-in. diameter trunk sewer, and abandonment of approximately 11,400 lf of 18-in. diameter sanitary force main.

Crews are using an Akkerman SL-30 MTBM to install the 36-in. Hobas pipe. The average drive length is 540 lf with the longest drive 690 lf.

The project began in July 2020 and is scheduled for completion in November 2021. The owner is the City of Houston. The designer is Amani Engineering Inc.


Virginia Beach

Virginia Beach Blvd Force Main Phase VI

Bradshaw Construction Corp.

Bradshaw Construction recently completed construction on a series of force main tunnels in Virginia Beach. Three drives, totaling 1,360 ft of 60-in. Permalok steel casing tunnel, were installed behind a Herrenknecht AVN-1200 MTBM. Mining conditions varied between sands, silts, and peat, all under the water table. Drives ranged from 280 to 750 ft, up to 40 ft deep. Steel sheeted launch and recovery shafts and 48-in. HDPE were installed by others. The project members include Hampton Roads Sanitation District (HRSD) (Owner), Kimley Horn LLP (Engineer) Bridgeman Civil Inc. (General Contractor) and Bradshaw Construction performing as tunneling subcontractor. Project Manager: Jordan Bradshaw.



Ship Canal Water Quality Project

The Lane Construction Company

The $254.9 million Ship Canal Water Quality Project for Seattle Public Utilities comprises 13,939 ft of 18-ft, 10-in. ID segmentally lined tunnel using a pressurized face TBM. Tunnel depth ranges from 35 to 85 ft below grade to top of tunnel. Also included is conveyance pipe casing under the Ship Canal installed via a curved microtunnel drive, 646 lf and 94-in. diameter.

There are five shaft sites: 1 slurry wall shaft – West Shaft site in Ballard (tunnel launch site); 3 secant pile shafts – Fremont site, Queen Anne site, and East Shaft site in Wallingford (tunnel exit shaft); and 1 drilled shaft using a steel casing – East Ballard site.

Anticipated ground conditions along the tunnel alignment consist of a highly variable mix of glacially over-consolidated soils.

The project is currently 10% complete. Crews have mobilized to all 5 shaft sites, and have completed the slurry wall at the West Shaft site. Upcoming work for the next 6 months includes construction of the five shafts

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 on average each year from flowing into the Lake Washington Ship Canal, Salmon Bay, and Lake Union.

The project is a joint project between two agencies: Seattle Public Utilities (Lead) and King County Department of Natural Resources and Parks. 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 2nd of 5 Projects in the SCWQP. There are 3 subsequent projects that also need to be complete as part of the SCWQP.

NTP was issued De. 26, 2019. Completion is expected by July 19, 2023.

Tunnel Designer: McMillian Jacobs and 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.




Sarnia Sewer Upgrade Project Phase 3 – Trunk Sewer Microtunneling

CRS Tunnelling Inc. Canada

The Sarnia Sewer Upgrade Project Phase 3 project includes four tunnel shafts constructed of steel ribs and wood lagging, 8 to 9 m in diameter, up to 13 m deep, and three microtunnel drives, 675, 617, and 498 m in length. The 617-m and 498-m drives have curves.

Pipe being installed is a 1,350-mm ID microtunnel pipe manufactured by Forterra. Geology is mainly clay, silty clay till, and clayey silt to silt. The bore is approximately 1.73 m. The longest drive is under CN rail yard and crosses 15 tracks.

The project started in January 2020, with all compounds and shafts completed as of September 2020. Tunneling has been delayed due to the pandemic. The overall project is expected to be complete by June 2021.

Owner: City of Sarnia; Engineer: Aecom; Equipment: Akkerman Slurry MTBM – SL60 with skin set; Contract value: $20 million (CAD).

Township of Dymond

Calamity Creek Culvert Replacement – Design Build

CRS Tunnelling Inc. Canada

This project comprises two tunnel drives, 150 m each, using earth pressure balance pipe jacking. The tunnels are separated by less than two tunnel diameters. Installed pipe is a 2,100-mm ID microtunnel pipe manufactured by Forterra. Geology is mainly clay, varved clay, cobbles and boulders. The bore is approximately 2.59 m (102 in.)

The two drives cross under Hwy 11, are separated by less than two tunnel diameters, and were constructed in grounds that had very low blow counts, sticky clays. During tunneling, contaminated ground and man-made wood obstruction were encountered. Mining also occurred during very frigid temperatures of northern Ontario.

The project began in June 2019 and was completed by December 2019.

Owner: Ministry of Transportation (MTO) North Bay; Prime Contractor: Construction DeMathieu & Bard (CDB); Engineer: Harbourside Engineering Consultants; Equipment: Lovat EPB Pipejacking TBM – 101-in. diameter; Contract value: $3.8 million (CAD).

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