The Mt. Lebanon tunnel is part of the light-rail transit improvement project of Pittsburgh's Port Authority of Allegheny County. The twin tunnels each are 756-m in length with a pump station and two cross passageways at intermediate points. The construction used was the New Austrian Tunneling Method, funded by UMTA as a research project, and an alternative design was prepared that represented a more conventional American design with cast-in-place concrete lining. Probable rock mass behavior during excavation was based on geological data and on information about other tunnels built in similar geology. While both portals had to be reinforced with steel ribs to avoid subsidence, the intermediate sections did utilize NATM. It was concluded that the optimum design might have been the primary support of rebar dowels from the conventional design combined with the lining of 100-mm of mesh-reinforced shotcrete of NATM. The application of NATM contractual practices to American underground construction was a significant achievement.

  • Availability:
  • Corporate Authors:

    Morgan-Grampian (Construction Press) Limited

    Morgan-Grampian House, 30 Calderwood Street
    London SE18 6QH,   England 
  • Authors:
    • Daly, W
    • Abramson, L W
  • Publication Date: 1986-1

Media Info

  • Features: Figures; Tables;
  • Pagination: p. 35-38
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00455134
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 31 1988 12:00AM