Schnabel-SWS is a strategic, North American alliance of two well-known tunnel engineering firms combining expertise and innovation to bring tunneling and underground solutions to some of infrastructure’s most complex challenges. Schnabel Engineering, formed in 1956, has over 425 professionals operating out of 22 U.S. offices. SWS Engineering, formed in 1982, has over 240 professionals operating in 8 countries.

Together, Schnabel-SWS provides tunnel and underground design services on transportation, water-related infrastructure, and hydroelectric power projects across the United States and Canada. Over the past 10 years, the firms have provided design services on a combined total of more than 500 miles (804 km) of tunnels. Our experience includes:

  • Highway tunnels
  • Freight rail tunnel expansions
  • Light rail tunnels and station designs
  • Power and lake tap tunnels
  • Water transmission conduits
  • Underground storage caverns
  • Combined sewer overflow tunnels
  • Storm drainage facilities

Whether in dense, urban settings or remote, difficult-to-access environments, our team has a history of providing unique design solutions to the complex alignment, geologic, and construction issues different locations present. It is through this broad experience that we’ve developed the niche technical expertise that manages risk on and adds value to underground projects. Our extensive expertise and project experience ranges from the smallest diameter trenchless installations to underground excavations with spans greater than 90 ft; includes shallow and deep tunnels in soil, rock, and mixed-face conditions (above and below the groundwater table); encompasses the full range of conventional and mechanized tunnel excavation methods; and utilizes the full suite of structural ground support techniques and ground improvement methods.

Together, Schnabel-SWS has worked on more than 250 underground projects worldwide and provides a diverse blend of skills pertaining to tunnels and other underground structures. Our services include:

  • Tunnel and shaft design
  • SEM/NATM design
  • Support of excavation and underpinning design
  • Numerical modeling
  • Ground improvement, dewatering, and grouting design
  • Building information modeling (BIM)
  • Risk assessment and management
  • Value engineering
  • Constructability reviews and cost estimating
  • Construction management and resident engineering
  • Geotechnical instrumentation and monitoring