Industry News, trenchless products
Project Profile:
Salt Lake City Public Utilities is increasing capacity and upgrading a portion of their sanitary sewer collection system from 1500 S – 2700 W to Redwood Road. The project bid in January 2019 and Whitaker Construction was selected as the low bidder. BTrenchless Inc. was awarded the grade-critical tunneled crossing of I-215, a major interstate in Salt Lake City. The tunnel was designed as a 466LF long, 48″ diameter steel casing with a future 30″ HOBAS carrier pipe skid in it afterwards. BTrenchless decided to upsize the casing to 51″ diameter to match the dimensions of their Akkerman SL51 Microtunnel Boring Machine (MTBM). The center of the tunnel was about 7FT below the water table with extremely soft soil consisting of lean clay, fat clay, and silty sand. This type of ground water and soil condition suits itself well for a MTBM installation method.
During design the team discovered an old as-built drawing of a now abandoned 12″ diameter concrete pipe in the path of the tunnel at approximately 320LF out. A series of GBM pilot tubes were installed ahead of the 51″ diameter tunnel launch in an attempt to proof the drive and find this pipe. Two of the
four pilot tube drives were deflected in this area; indicating that something was out there. After lots of internal discussions the decision was made to carry on with the original design and attempt to tunnel through this questionable area at 320LF out. While carefully tunneling through this area, a large pocket of river rock was discovered, but no remnants of any concrete pipe were ever found. This was great news for the project team. The end result was a successfully installed 51″ casing under I-215 for Salt Lake City Public Utilities, allowing Whitaker Construction to continue on with their project as planned.
Photos: Morty the Tunnel Rat and two members of the BTrenchless Crew getting ready for an Akkerman MTBM launch.
Industry News, trenchless products
Project: C470 Managed Lanes
Owner: CDOT
General Contractor: Flatiron / AECOM Joint Venture
Tunneling Subcontractor: BTrenchless (A Division of BT Construction, Inc.)
BTrenchless is the tunneling subcontractor for Flatiron/AECOM Joint Venture for the expansion of the C470 corridor on the South side of the Denver Metro area.
BTrenchless has completed the following drives on this project:
- 362 LF of 42” RCP was installed using the Akkerman 420 Tunnel Boring Machine.
- 324 LF of 48” RCP was installed using the Akkerman 480 Tunnel Boring Machine.
- 387 LF of 72” RCP was installed using the Akkerman 720 Tunnel Boring Machine.
- 355 LF of 72” RCP. This storm sewer line is in a redesign phase and will be installed using the Akkerman 720 Tunnel Boring Machine.
- 267 LF of 66” RCP. This tunnel is in the final design phase and will be installed using the Akkerman 660 Tunnel Boring Machine.
The main challenges encountered during this project were an abandoned 48” steel waterline and an abandoned 12” AC waterline that were found during our 72” RCP tunnel drive. We first encountered the 48” steel waterline and had to remove a section of the waterline through the head of the 720 TBM, as we continued the drive another 30 LF, we encountered a 12” AC waterline that had to be abated and removed through the head of the 720 TBM, as well.
Overall, this tunneling project has been a success for all parties involved, despite the challenges that we have encountered.
As always, Morty the Tunnel Rat is on hand to supervise the project!
Industry News, trenchless projects
The City and County of Denver has designed the 33rd Street Outfall Storm Sewer to reduce flooding concerns between Downing Street and the Platte River along 33rd Street and the surrounding neighborhoods. The project is being released in four phases over three years, and BTrenchless has completed the first two phases, installing the storm sewer from the Platte River to the intersection of 33rd and Blake.
The pipeline is a combination of large box culverts, 120” HOBAS pipe, smaller reinforced concrete pipe, and steel casings. The highlight of the first phase was construction of a precast 11’ x 8’ concrete box culvert across Brighton Blvd. while maintaining a constant flow of traffic. The second phase included a 220’ long tunnel, ten foot in diameter, under the Union Pacific Railroad Yard and the RTD Commuter Rail. It also included side-by-side 96” diameter steel tunnels under Blake Street and a 450 foot long, 51” HOBAS storm lateral via a microtunnel method.
The diversity of this project allowed BTrenchless to utilize three different types of tunnels and capitalized on the vast resources of both people and equipment to successfully complete this complex and high profile project. In the course of the first two phases, nine different crews and four different superintendents had a part in the overall success of the project, each capitalizing on their various areas of expertise.
Click on photos to view larger images. Be sure to notice Morty the Tunnel Rat in the top photo supervising the project!
Industry News, trenchless people
Mortimer the Sewer Rat and now his protege, Morty Jr., have been busy traveling around the country raising the awareness for trenchless technology! This year Morty traveled with Iowa Trenchless and with Michael Bryne Manufacturing.
Just yesterday, Morty and Jim Weist, CEO and President of Michael Bryne Manufacturing, headed south in the snow with an 84″ diameter auger and cutting head for a project!
Iowa Trenchless and Michael Bryne Manufacturing generously sponsored Morty this past year by winning him during NASTT’s 2017 Educational Fund Auction. Interested in sponsoring Morty for 2018?
Join us at the auction in Palm Springs, Monday, March 26!
Salt Lake City Public Utilities is increasing capacity and upgrading a portion of their sanitary sewer collection system from 1500 S – 2700 W to Redwood Road. The project bid in January 2019 and Whitaker Construction was selected as the low bidder. BTrenchless Inc. was awarded the grade-critical tunneled crossing of I-215, a major interstate in Salt Lake City. The tunnel was designed as a 466LF long, 48″ diameter steel casing with a future 30″ HOBAS carrier pipe skid in it afterwards. BTrenchless decided to upsize the casing to 51″ diameter to match the dimensions of their Akkerman SL51 Microtunnel Boring Machine (MTBM). The center of the tunnel was about 7FT below the water table with extremely soft soil consisting of lean clay, fat clay, and silty sand. This type of ground water and soil condition suits itself well for a MTBM installation method.
