RiverRenew Tunnel Boring Machine Completes Factory Acceptance Testing

The RiverRenew Tunnel Project in Alexandria, Virginia, reached another major milestone as the tunnel boring machine (TBM) achieved completion of the factory acceptance test on April 29, 2022.

The test comes at the end of the machine design and fabrication effort by Herrenknecht in Schwanau, Germany. Engineers and mechanics from the RiverRenew team traveled to Germany to rigorously examine and test every component of the machine, demonstrate that all systems function as designed, and make any final necessary adjustments while the machine is still at the factory.

The TBM will now be disassembled and prepared for her journey across the Atlantic to Alexandria and is set to arrive in late June. Here are some fun facts about Alexandria’s subterranean star:

  • Diameter: 14 feet, 8 inches
  • Length: 465 feet
  • Weight: 400 tons
  • Top speed: 100 millimeters per minute (snail-paced)
  • Cutterhead speed: 4.5 rotations per minute


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

For additional information, visit AlexRenew’s Facebook and Twitter pages.

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