Although large-diameter welding is a core specialty of Dean’s Certified Welding Services, our team routinely handles the fit-up assembly and welding of large-diameter Tunnel Boring Machines. We have worked on some of the largest in North America, including some of the largest steel water pipelines installed on the continent.

Our experience includes:

• Herrenknecht TBM – Impregilo/Healy/Parsons JV – Anacostia River Tunnel Project – Washington, D.C.
• Robbins TBM – Kiewit/Shea AJV – Rondout Bypass Tunnel – Newburgh, NY
• Herrenknecht TBM – Regional Connector Constructors – No. C0980 Regional Connector Transit Corridor Design Build – Los Angeles, CA
• Herrenknecht TBM – Kenny/Obayashi AJV – South Hartford Conveyance and Storage Tunnel Project – Hartford, CT
• Herrenknecht TBM – Frontier Kemper/Tutor Perini – Purple Line Extension Section 3 – Los Angeles, CA
• Herrenknecht TBM – Lane Construction – Ship Canal Water Quality Project – Seattle, WA

These projects demand advanced welding techniques, precise alignment, and strict quality control due to wall thickness, material stress, and long-term operational requirements. This expertise allows us to support contractors and agencies on projects where precision, experience, and proven performance are non-negotiable.