Case Study: West Virginia US Highway 19 "The Narrows" Rockfall Mitigation

U.S. Highway 19 connects the city of Weston, West Virginia to neighboring counties. Along one cut-slope in Weston, there was little catchment along the highway and rockfall was a hazardous problem. KANE GeoTech, Inc., Geobrugg North America, LLC, and the West Virginia Department of Transportation worked together to develop a rockfall mitigation system relying on new materials and technologies. The cut slope was approximately 900-ft long with vertical slope heights varying from approximately 20-ft to 65-ft. The upper slope was composed of a 20-ft thick massive sandstone bed. Directly underneath the sandstone was a 35-foot thick layer of black to brown shale with coal seams and lenses. Just beneath the shale layer was a 5-ft section of massive sandstone. Massive rockfall was due to relatively large joint spacing in the sandstone combined with rapid weathering of the underlying shale and coal layers. Rockfall on most of the slope was mitigated using a new type of heavy drapery system of high strength 4-mm twisted steel wires forming rhomboids. This material was used, instead of more traditional cable nets, to prevent smaller sandstone blocks in the lower beds and slabs of shale from falling onto the road. The sandstone in the upper slope was approximately 55-ft above the roadway grade. These outcrops cantilevered up to 10-ft from the slope surface. The risk of massive rockfall in this area was significant and a drapery was considered inadequate. Instead, a tensioned high strength steel wire mesh system composed of twisted 4-mm wires in a diamond pattern was used. This system was designed to actively hold the sandstone blocks on the slope and prevent any movement. The project was bid as a conceptual design with design-build aspects by the Engineer and the Manufacturer. The Owner, West Virginia DOT, and the Contractor, Ameritech Slope Constructors also worked to overcome design and constructability issues. The successful installation and on-time completion demonstrated the advantages of all stake holders working as a team rather than in adversarial relationships.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References; Tables;
  • Pagination: pp 181-193
  • Monograph Title: Proceedings of the 63rd Annual Highway Geology Symposium (HGS 2012)

Subject/Index Terms

Filing Info

  • Accession Number: 01661541
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 14 2018 8:21PM